[{"Name":"The Endocrine System","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Introduction to the Endocrine System","Duration":"6m 32s","ChapterTopicVideoID":28679,"CourseChapterTopicPlaylistID":286911,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:02.925","Text":"Hi, welcome back."},{"Start":"00:02.925 ","End":"00:07.935","Text":"We\u0027ve been discussing various systems in biology,"},{"Start":"00:07.935 ","End":"00:16.980","Text":"and now we\u0027re going to be discussing the endocrine system which controls the production,"},{"Start":"00:16.980 ","End":"00:23.160","Text":"secretion, and regulation of something you\u0027ve all heard of, hormones."},{"Start":"00:23.160 ","End":"00:26.880","Text":"What is the endocrine system?"},{"Start":"00:26.880 ","End":"00:30.930","Text":"Hormones serve as chemical agents,"},{"Start":"00:30.930 ","End":"00:34.540","Text":"so hormones are chemicals."},{"Start":"00:34.540 ","End":"00:40.250","Text":"They\u0027re are chemical signals that go between organs in the body,"},{"Start":"00:40.250 ","End":"00:44.860","Text":"and they\u0027re usually carried by the circulatory system."},{"Start":"00:44.860 ","End":"00:52.760","Text":"We\u0027re talking now about chemicals that are moving between various organs of the body."},{"Start":"00:52.760 ","End":"01:00.320","Text":"It plays a very central role in all things that go on inside multicellular organisms,"},{"Start":"01:00.320 ","End":"01:03.770","Text":"including growth, metabolism, and sexual development."},{"Start":"01:03.770 ","End":"01:06.140","Text":"That is, what are they doing?"},{"Start":"01:06.140 ","End":"01:08.720","Text":"They are connecting different cells,"},{"Start":"01:08.720 ","End":"01:11.480","Text":"sending signals to different cells saying, \"Hey,"},{"Start":"01:11.480 ","End":"01:15.580","Text":"I\u0027m doing this and you should be doing that.\""},{"Start":"01:15.580 ","End":"01:17.360","Text":"An example, for instance,"},{"Start":"01:17.360 ","End":"01:20.285","Text":"is that in organisms that undergo metamorphosis,"},{"Start":"01:20.285 ","End":"01:24.740","Text":"like butterflies started out as caterpillars and they end up as butterflies."},{"Start":"01:24.740 ","End":"01:31.060","Text":"Yes. The process is controlled by an endocrine system."},{"Start":"01:31.060 ","End":"01:35.120","Text":"In other words, there are hormones that are secreted"},{"Start":"01:35.120 ","End":"01:38.765","Text":"by various cells as the butterfly develops,"},{"Start":"01:38.765 ","End":"01:43.715","Text":"telling it what the cells should be doing and how they should be developing."},{"Start":"01:43.715 ","End":"01:45.950","Text":"In organisms that are more like us,"},{"Start":"01:45.950 ","End":"01:47.720","Text":"let\u0027s say this is a kidney,"},{"Start":"01:47.720 ","End":"01:53.270","Text":"so the kidney needs to be controlled by and"},{"Start":"01:53.270 ","End":"01:56.210","Text":"also to send out signals to other parts of"},{"Start":"01:56.210 ","End":"01:59.810","Text":"the body about what\u0027s going on with this kidney."},{"Start":"01:59.810 ","End":"02:07.025","Text":"Maintaining homeostasis requires this communication of different systems."},{"Start":"02:07.025 ","End":"02:11.420","Text":"In this picture here you can see that there is something which is sitting on top of"},{"Start":"02:11.420 ","End":"02:17.050","Text":"the kidney that is connecting with the rest of the body through these blood vessels."},{"Start":"02:17.050 ","End":"02:20.840","Text":"Here\u0027s a capillary and there are various chemicals going in"},{"Start":"02:20.840 ","End":"02:24.830","Text":"and out that are going to be going to other parts of the body,"},{"Start":"02:24.830 ","End":"02:28.770","Text":"telling the rest of the body what\u0027s going on with this kidney."},{"Start":"02:28.770 ","End":"02:33.320","Text":"We\u0027re talking about communication between distance cells and"},{"Start":"02:33.320 ","End":"02:37.650","Text":"tissues through the release of chemical signals,"},{"Start":"02:37.650 ","End":"02:40.925","Text":"and those chemical signals are called hormones."},{"Start":"02:40.925 ","End":"02:45.140","Text":"They\u0027re carried usually by the blood to all parts of the body,"},{"Start":"02:45.140 ","End":"02:50.960","Text":"and they are then picked up by target cells where there are"},{"Start":"02:50.960 ","End":"02:57.850","Text":"receptors that are very specific for the specific hormones."},{"Start":"02:57.850 ","End":"03:02.600","Text":"The endocrine system is the system in which there are cells,"},{"Start":"03:02.600 ","End":"03:07.175","Text":"tissues, and organs that secrete hormones."},{"Start":"03:07.175 ","End":"03:12.350","Text":"The endocrine system is the system in which"},{"Start":"03:12.350 ","End":"03:18.425","Text":"various chemicals are secreted either by cells or,"},{"Start":"03:18.425 ","End":"03:23.230","Text":"we can talk about tissues or even organs that secrete these various tissues."},{"Start":"03:23.230 ","End":"03:28.429","Text":"Now let\u0027s look and see what these hormones are chemically."},{"Start":"03:28.429 ","End":"03:30.740","Text":"There are all sorts of different hormones,"},{"Start":"03:30.740 ","End":"03:35.690","Text":"but actually they can be divided into groups by their chemical structure,"},{"Start":"03:35.690 ","End":"03:37.415","Text":"and there aren\u0027t that many."},{"Start":"03:37.415 ","End":"03:41.300","Text":"There are those that are lipid-derived, in other words,"},{"Start":"03:41.300 ","End":"03:45.365","Text":"the biochemistry or the biosynthesis of"},{"Start":"03:45.365 ","End":"03:51.755","Text":"these hormones are made initially from something which is more like a lipid,"},{"Start":"03:51.755 ","End":"03:56.060","Text":"or they can come from something which is more related"},{"Start":"03:56.060 ","End":"04:00.670","Text":"to proteins like amino-acid derived or sometimes they\u0027re peptides."},{"Start":"04:00.670 ","End":"04:05.930","Text":"As you know, lipids should be able to cross the plasma membrane,"},{"Start":"04:05.930 ","End":"04:10.130","Text":"because the plasma membrane is a lipid bilayer."},{"Start":"04:10.130 ","End":"04:15.980","Text":"Lipids-derived hormones can diffuse across the plasma membrane,"},{"Start":"04:15.980 ","End":"04:22.280","Text":"but amino acid-derived or peptide hormones cannot get across the plasma membrane."},{"Start":"04:22.280 ","End":"04:25.040","Text":"How are they going to be detected inside the cell?"},{"Start":"04:25.040 ","End":"04:29.725","Text":"Well, there is a receptor protein embedded in"},{"Start":"04:29.725 ","End":"04:34.510","Text":"the plasma membrane which will receive the signal from the peptide hormone."},{"Start":"04:34.510 ","End":"04:35.630","Text":"Then as you might guess,"},{"Start":"04:35.630 ","End":"04:43.435","Text":"there will be some signal transduction pathway leading into the cell that will say,"},{"Start":"04:43.435 ","End":"04:47.150","Text":"okay, I have seen such and such a hormone,"},{"Start":"04:47.150 ","End":"04:51.620","Text":"such and such peptide hormone or amino acid hormone."},{"Start":"04:51.620 ","End":"04:56.435","Text":"Now let\u0027s look at the lipid derived hormones more closely."},{"Start":"04:56.435 ","End":"05:01.400","Text":"It turns out that most of them are steroid hormones."},{"Start":"05:01.400 ","End":"05:05.285","Text":"That means that they are derived chemically from cholesterol."},{"Start":"05:05.285 ","End":"05:09.998","Text":"Here\u0027s cholesterol, have a look at this 1,"},{"Start":"05:09.998 ","End":"05:12.155","Text":"2, 3, 4 ringed structure."},{"Start":"05:12.155 ","End":"05:16.845","Text":"This is cholesterol because it has an alcohol,"},{"Start":"05:16.845 ","End":"05:18.210","Text":"OL at the end,"},{"Start":"05:18.210 ","End":"05:19.530","Text":"and we\u0027ll see this in a second,"},{"Start":"05:19.530 ","End":"05:21.620","Text":"and they\u0027re structurally similar to it."},{"Start":"05:21.620 ","End":"05:25.400","Text":"Interestingly here we\u0027ve got estradiol, a female hormone,"},{"Start":"05:25.400 ","End":"05:29.310","Text":"and testosterone, a male hormone,"},{"Start":"05:29.310 ","End":"05:32.660","Text":"and both of them actually look quite similar chemically."},{"Start":"05:32.660 ","End":"05:34.370","Text":"If you look at them, there\u0027s some differences."},{"Start":"05:34.370 ","End":"05:36.710","Text":"There\u0027s a methyl group here on testosterone."},{"Start":"05:36.710 ","End":"05:40.100","Text":"But the big difference is going to be"},{"Start":"05:40.100 ","End":"05:45.860","Text":"that estradiol is an alcohol"},{"Start":"05:45.860 ","End":"05:50.240","Text":"because it has this hydroxyl group at one end and the other one,"},{"Start":"05:50.240 ","End":"05:53.839","Text":"testosterone, is going to be a ketone."},{"Start":"05:53.839 ","End":"05:58.565","Text":"Here you can see this ketone as opposed to the alcohol,"},{"Start":"05:58.565 ","End":"06:01.325","Text":"that\u0027s at the end of the estradiol."},{"Start":"06:01.325 ","End":"06:11.360","Text":"Therefore, the names of these are also appropriately named \"-ol\" estradiol."},{"Start":"06:11.360 ","End":"06:15.410","Text":"If they end in an alcohol or if they are alcohols,"},{"Start":"06:15.410 ","End":"06:18.025","Text":"or if they\u0027re ketones,"},{"Start":"06:18.025 ","End":"06:21.195","Text":"like testosterone was a ketone,"},{"Start":"06:21.195 ","End":"06:25.425","Text":"so it will end with \"-one\" for ketones."},{"Start":"06:25.425 ","End":"06:32.550","Text":"Here you\u0027ve got these examples of estradiol and testosterone as I\u0027ve shown you below."}],"ID":30223},{"Watched":false,"Name":"Hormones","Duration":"5m 18s","ChapterTopicVideoID":28678,"CourseChapterTopicPlaylistID":286911,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.190","Text":"Hi. I\u0027m glad you\u0027re back to continue our discussion of the endocrine system."},{"Start":"00:05.190 ","End":"00:08.205","Text":"We were talking in our previous video about"},{"Start":"00:08.205 ","End":"00:14.610","Text":"lipid-derived hormones, lipid-soluble hormones,"},{"Start":"00:14.610 ","End":"00:18.180","Text":"and remember that many of them,"},{"Start":"00:18.180 ","End":"00:21.120","Text":"at least, were products of,"},{"Start":"00:21.120 ","End":"00:24.465","Text":"or similar to, cholesterol."},{"Start":"00:24.465 ","End":"00:32.100","Text":"Cholesterol served as a basis for their continued biochemistry."},{"Start":"00:32.100 ","End":"00:36.500","Text":"Steroid hormones though, must be insoluble in water."},{"Start":"00:36.500 ","End":"00:41.540","Text":"So the question arises: How are they transported through the blood because,"},{"Start":"00:41.540 ","End":"00:43.775","Text":"if they\u0027re not soluble in water,"},{"Start":"00:43.775 ","End":"00:46.895","Text":"then they won\u0027t be soluble in blood?"},{"Start":"00:46.895 ","End":"00:48.665","Text":"The way that happens,"},{"Start":"00:48.665 ","End":"00:50.525","Text":"the way they move through the blood,"},{"Start":"00:50.525 ","End":"00:56.930","Text":"is that they become attached to a transport protein."},{"Start":"00:56.930 ","End":"01:01.580","Text":"The transport protein is soluble in water, in the blood."},{"Start":"01:01.580 ","End":"01:09.140","Text":"Therefore, the fat-soluble globule can move through the bloodstream,"},{"Start":"01:09.140 ","End":"01:15.350","Text":"and it can therefore also deposit the fat globule,"},{"Start":"01:15.350 ","End":"01:17.855","Text":"or the lipid globule,"},{"Start":"01:17.855 ","End":"01:20.150","Text":"on the surface of a plasma membrane,"},{"Start":"01:20.150 ","End":"01:22.325","Text":"and then it can diffuse through."},{"Start":"01:22.325 ","End":"01:26.810","Text":"Notice here the receptor is inside the cell, in this case,"},{"Start":"01:26.810 ","End":"01:31.745","Text":"inside the nucleus, even of the receptor cell."},{"Start":"01:31.745 ","End":"01:34.720","Text":"Let\u0027s see how this happens."},{"Start":"01:34.720 ","End":"01:39.965","Text":"A consequence actually of this system is that"},{"Start":"01:39.965 ","End":"01:44.720","Text":"they remain in circulation considerably longer than peptide hormones."},{"Start":"01:44.720 ","End":"01:49.010","Text":"I want to give you an idea of how quickly these things can"},{"Start":"01:49.010 ","End":"01:53.915","Text":"degrade or can stay inside the bloodstream."},{"Start":"01:53.915 ","End":"01:57.020","Text":"Cortisol, which is,"},{"Start":"01:57.020 ","End":"01:59.240","Text":"of course, soluble in water,"},{"Start":"01:59.240 ","End":"02:02.105","Text":"\"ol\" means that it\u0027s an alcohol,"},{"Start":"02:02.105 ","End":"02:05.480","Text":"has a half-life of about 60-90 minutes."},{"Start":"02:05.480 ","End":"02:06.695","Text":"What\u0027s a half-life?"},{"Start":"02:06.695 ","End":"02:13.250","Text":"The half-life is the time that elapses in which about 50 percent,"},{"Start":"02:13.250 ","End":"02:16.937","Text":"half, of this material disappears."},{"Start":"02:16.937 ","End":"02:20.915","Text":"So in 60-90 minutes, cortisol is half-gone."},{"Start":"02:20.915 ","End":"02:23.105","Text":"On the other hand, epinephrine,"},{"Start":"02:23.105 ","End":"02:25.910","Text":"so that\u0027s an amino acid-derived hormone,"},{"Start":"02:25.910 ","End":"02:31.590","Text":"has a half-life of approximately 1 minute."},{"Start":"02:32.270 ","End":"02:36.675","Text":"Cortisol is the lipid, \"ol\","},{"Start":"02:36.675 ","End":"02:41.315","Text":"that\u0027s an alcohol, but it is derived from a lipid,"},{"Start":"02:41.315 ","End":"02:50.730","Text":"has a much longer half-life than the amino acid-derived hormone which is water-soluble."},{"Start":"02:51.280 ","End":"02:56.570","Text":"Let\u0027s look now at amino acid-derived hormones."},{"Start":"02:56.570 ","End":"02:58.790","Text":"In particular, we\u0027ll put 2 amino acids,"},{"Start":"02:58.790 ","End":"03:06.050","Text":"tyrosine and tryptophan, which serve as basis for a number of different hormones."},{"Start":"03:06.050 ","End":"03:11.365","Text":"You can see epinephrine is quite similar to tyrosine,"},{"Start":"03:11.365 ","End":"03:17.040","Text":"and melatonin is quite similar to tryptophan."},{"Start":"03:17.620 ","End":"03:26.180","Text":"If you look at it, the difference between epinephrine and tyrosine really is very small,"},{"Start":"03:26.180 ","End":"03:30.530","Text":"and the difference between melatonin and tryptophan is quite small."},{"Start":"03:30.530 ","End":"03:32.150","Text":"Look at the R groups over here."},{"Start":"03:32.150 ","End":"03:38.870","Text":"But in any case, we also name these hormones based on what they come from,"},{"Start":"03:38.870 ","End":"03:43.895","Text":"just as we saw in the cholesterol-based hormones."},{"Start":"03:43.895 ","End":"03:48.635","Text":"The chemical name will end in \"ine\" or sometimes in \"in\","},{"Start":"03:48.635 ","End":"03:52.700","Text":"if they come from these amino acids."},{"Start":"03:52.700 ","End":"03:55.160","Text":"Epinephrine and norepinephrine,"},{"Start":"03:55.160 ","End":"03:58.395","Text":"\"ine\" at the end, thyroxine,"},{"Start":"03:58.395 ","End":"04:01.430","Text":"\"ine\" at the end, or melatonin just \"in\","},{"Start":"04:01.430 ","End":"04:06.600","Text":"each of these is derived from an amino acid."},{"Start":"04:06.730 ","End":"04:09.605","Text":"In the case of peptide hormones,"},{"Start":"04:09.605 ","End":"04:12.560","Text":"we\u0027re talking about a polypeptide chain,"},{"Start":"04:12.560 ","End":"04:17.360","Text":"not just 1 amino acid because a polypeptide is a chain of amino acids,"},{"Start":"04:17.360 ","End":"04:20.690","Text":"and those include various hormones, for instance,"},{"Start":"04:20.690 ","End":"04:22.400","Text":"the antidiuretic hormone,"},{"Start":"04:22.400 ","End":"04:25.490","Text":"ADH, or oxytocin,"},{"Start":"04:25.490 ","End":"04:29.675","Text":"and also growth hormones,"},{"Start":"04:29.675 ","End":"04:32.690","Text":"or FSH, follicle stimulating hormone,"},{"Start":"04:32.690 ","End":"04:35.465","Text":"which is involved in ovulation in women."},{"Start":"04:35.465 ","End":"04:39.880","Text":"Amino acid-derived polypeptide hormones are water-soluble."},{"Start":"04:39.880 ","End":"04:43.610","Text":"Therefore, they can go through the bloodstream,"},{"Start":"04:43.610 ","End":"04:45.844","Text":"simply dissolved in the bloodstream,"},{"Start":"04:45.844 ","End":"04:51.725","Text":"and they cannot pass through plasma membranes."},{"Start":"04:51.725 ","End":"04:54.050","Text":"They\u0027re not going to be soluble in plasma membranes,"},{"Start":"04:54.050 ","End":"05:01.460","Text":"and therefore the receptor for them is going to have to be on the target cell."},{"Start":"05:01.460 ","End":"05:03.680","Text":"Thus, the receptor is going to have to be on"},{"Start":"05:03.680 ","End":"05:07.190","Text":"the target cell on the outside in the plasma membrane."},{"Start":"05:07.190 ","End":"05:09.395","Text":"Then as we mentioned earlier,"},{"Start":"05:09.395 ","End":"05:16.740","Text":"there\u0027ll be a signal transduction pathway which will lead the signal into the nucleus."}],"ID":30224}],"Thumbnail":null,"ID":286911},{"Name":"How Hormones Work","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Hormones and Receptors","Duration":"10m 11s","ChapterTopicVideoID":28680,"CourseChapterTopicPlaylistID":286912,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.070","Text":"Welcome back to our discussion about how hormones work."},{"Start":"00:05.070 ","End":"00:07.680","Text":"In this video, we\u0027re going to be describing"},{"Start":"00:07.680 ","End":"00:12.375","Text":"hormone-receptor interactions and what the result of that is."},{"Start":"00:12.375 ","End":"00:18.075","Text":"Now in this figure, you see actually a very beautiful diagram of a hormone,"},{"Start":"00:18.075 ","End":"00:19.670","Text":"which is in the center here,"},{"Start":"00:19.670 ","End":"00:24.525","Text":"and it is sitting in the pocket of a receptor."},{"Start":"00:24.525 ","End":"00:26.730","Text":"You can see the receptor is all around it."},{"Start":"00:26.730 ","End":"00:29.220","Text":"In this case, there are some alpha helices and"},{"Start":"00:29.220 ","End":"00:33.585","Text":"the beta sheets that make specific contacts with the hormone."},{"Start":"00:33.585 ","End":"00:37.020","Text":"They bind to specific sites,"},{"Start":"00:37.020 ","End":"00:40.425","Text":"making this specificity very great."},{"Start":"00:40.425 ","End":"00:47.915","Text":"Now the receptors for a specific hormone can be found on different tissues,"},{"Start":"00:47.915 ","End":"00:52.105","Text":"or only unspecialized cells in 1 tissue."},{"Start":"00:52.105 ","End":"00:59.415","Text":"For example, it could be that that thyroid hormones act on many different tissue types."},{"Start":"00:59.415 ","End":"01:04.820","Text":"Let\u0027s say this hormone here is a thyroid hormone,"},{"Start":"01:04.820 ","End":"01:09.220","Text":"and they\u0027re acting as you can see on different cell types."},{"Start":"01:09.220 ","End":"01:11.795","Text":"On the other hand,"},{"Start":"01:11.795 ","End":"01:14.305","Text":"and this is not shown in this figure here,"},{"Start":"01:14.305 ","End":"01:22.330","Text":"other hormones like LH or FSH can be restricted only to 1 tissue type to the ovary."},{"Start":"01:22.330 ","End":"01:30.350","Text":"What this figure does show is that cells can have many receptors for a single hormone,"},{"Start":"01:30.350 ","End":"01:33.260","Text":"let\u0027s say this one would have many receptors for"},{"Start":"01:33.260 ","End":"01:36.650","Text":"this particular hormone and this red one,"},{"Start":"01:36.650 ","End":"01:41.570","Text":"which you can see also has a shape that\u0027 s recognized here and there are many of them."},{"Start":"01:41.570 ","End":"01:45.785","Text":"Sometimes they can possess different receptors,"},{"Start":"01:45.785 ","End":"01:49.895","Text":"here you can see the Y-shaped ones fit the yellow hormone,"},{"Start":"01:49.895 ","End":"01:53.240","Text":"and in addition, can fit the red hormone,"},{"Start":"01:53.240 ","End":"01:55.295","Text":"the one that has this circular kind."},{"Start":"01:55.295 ","End":"02:01.590","Text":"In this case, we have a target cell that can see both hormones A and B."},{"Start":"02:01.690 ","End":"02:09.020","Text":"Now, we can also have different numbers of the receptors that are on the outside of"},{"Start":"02:09.020 ","End":"02:15.565","Text":"the cell and that will determine how sensitive the cell is to the hormone."},{"Start":"02:15.565 ","End":"02:19.730","Text":"The number of receptors per hormone determines the cell sensitivity to"},{"Start":"02:19.730 ","End":"02:25.114","Text":"that hormone and that then can make a difference in how the cells respond."},{"Start":"02:25.114 ","End":"02:30.660","Text":"The number of receptors can also change over time,"},{"Start":"02:30.660 ","End":"02:35.930","Text":"and that can change the sensitivity of the cell."},{"Start":"02:35.930 ","End":"02:38.695","Text":"We can have down-regulation."},{"Start":"02:38.695 ","End":"02:40.055","Text":"That is that, over time,"},{"Start":"02:40.055 ","End":"02:42.965","Text":"the number of receptors decreases."},{"Start":"02:42.965 ","End":"02:46.505","Text":"You can see here that the numbers are going down."},{"Start":"02:46.505 ","End":"02:48.725","Text":"There are many receptors of the cell,"},{"Start":"02:48.725 ","End":"02:51.635","Text":"whereas with time, there are fewer,"},{"Start":"02:51.635 ","End":"02:54.035","Text":"or you can have the opposite."},{"Start":"02:54.035 ","End":"02:56.195","Text":"You can have up-regulation,"},{"Start":"02:56.195 ","End":"02:58.955","Text":"where with time, the number of receptors goes up,"},{"Start":"02:58.955 ","End":"03:03.560","Text":"making these cells more sensitive whereas the ones"},{"Start":"03:03.560 ","End":"03:08.720","Text":"that the upper part of the figure become less sensitive with time."},{"Start":"03:08.720 ","End":"03:12.515","Text":"Now let\u0027s look at how these hormones bind with the cell."},{"Start":"03:12.515 ","End":"03:15.710","Text":"The binding alter cellular activity and can"},{"Start":"03:15.710 ","End":"03:19.655","Text":"result in an increase or decrease in various processes."},{"Start":"03:19.655 ","End":"03:23.915","Text":"They can bind directly, so for instance,"},{"Start":"03:23.915 ","End":"03:30.200","Text":"the steroid hormone here is going to be binding a receptor directly,"},{"Start":"03:30.200 ","End":"03:32.030","Text":"which in this case, in this figure,"},{"Start":"03:32.030 ","End":"03:33.425","Text":"is moving in the cell,"},{"Start":"03:33.425 ","End":"03:35.930","Text":"and that will modulate gene transcription."},{"Start":"03:35.930 ","End":"03:40.820","Text":"So the hormone itself is binding to a receptor and"},{"Start":"03:40.820 ","End":"03:47.120","Text":"that receptor is doing the work but that is called a direct interaction,"},{"Start":"03:47.120 ","End":"03:49.361","Text":"or it can be indirect because it"},{"Start":"03:49.361 ","End":"03:53.090","Text":"combined indirectly and that binds now just the cell surface,"},{"Start":"03:53.090 ","End":"03:56.780","Text":"that is, the hormone cannot get into the cell."},{"Start":"03:56.780 ","End":"04:01.535","Text":"That\u0027s the difference between direct and indirect binding."},{"Start":"04:01.535 ","End":"04:03.530","Text":"Now something else happens."},{"Start":"04:03.530 ","End":"04:08.220","Text":"There\u0027s a signal transduction pathway which is going to cause the effect."},{"Start":"04:08.220 ","End":"04:12.920","Text":"So that will be an indirect hormone response, which we\u0027ll see."},{"Start":"04:12.920 ","End":"04:19.185","Text":"As an example of that will be with peptides that cannot get through the cell surface."},{"Start":"04:19.185 ","End":"04:23.630","Text":"Let\u0027s now look at the direct interactions"},{"Start":"04:23.630 ","End":"04:27.695","Text":"with lipid-soluble hormones like steroid hormones,"},{"Start":"04:27.695 ","End":"04:32.270","Text":"because they can diffuse across the membranes of the endocrine cell,"},{"Start":"04:32.270 ","End":"04:36.890","Text":"the cell now which is going to be receiving the signal."},{"Start":"04:36.890 ","End":"04:40.460","Text":"You remember that those steroid hormones in"},{"Start":"04:40.460 ","End":"04:45.410","Text":"the bloodstream cannot dissolve in the bloodstream itself."},{"Start":"04:45.410 ","End":"04:48.710","Text":"They are bound to some sort of transport proteins,"},{"Start":"04:48.710 ","End":"04:57.255","Text":"but then the transport proteins then stay outside the cell and release the steroids,"},{"Start":"04:57.255 ","End":"04:59.360","Text":"or the steroid hormones,"},{"Start":"04:59.360 ","End":"05:03.500","Text":"or lipid-soluble hormones through the cell membrane where they will"},{"Start":"05:03.500 ","End":"05:09.650","Text":"encounter a receptor that could be in the nucleus or it could be in the cytoplasm."},{"Start":"05:09.650 ","End":"05:13.325","Text":"But in any case, the steroid hormone itself"},{"Start":"05:13.325 ","End":"05:17.980","Text":"goes through the cell membrane and that would make it a direct response,"},{"Start":"05:17.980 ","End":"05:19.445","Text":"as I said before."},{"Start":"05:19.445 ","End":"05:26.690","Text":"The hormones then act as transcription regulators in the sense that they,"},{"Start":"05:26.690 ","End":"05:28.910","Text":"together with the receptor,"},{"Start":"05:28.910 ","End":"05:32.105","Text":"actually physically will bind to the DNA,"},{"Start":"05:32.105 ","End":"05:35.900","Text":"changing the synthesis of messenger RNA, that is,"},{"Start":"05:35.900 ","End":"05:44.260","Text":"inducing or reducing the amount of messenger RNA for a specific gene or genes."},{"Start":"05:44.260 ","End":"05:49.235","Text":"The changing gene expression here,"},{"Start":"05:49.235 ","End":"05:51.248","Text":"we can see over here,"},{"Start":"05:51.248 ","End":"05:57.410","Text":"changes at the end of the day the amount of protein that is synthesized."},{"Start":"05:57.410 ","End":"06:00.950","Text":"Of course, the protein can be used to either"},{"Start":"06:00.950 ","End":"06:04.760","Text":"change the structure of the cell or there\u0027s some other downstream effects."},{"Start":"06:04.760 ","End":"06:06.905","Text":"Let\u0027s say that if that protein is an enzyme,"},{"Start":"06:06.905 ","End":"06:12.694","Text":"that can catalyze chemical reactions and change the way the cell behaves."},{"Start":"06:12.694 ","End":"06:18.335","Text":"Now non-steroid hormones, like vitamin D and thyroxine,"},{"Start":"06:18.335 ","End":"06:22.670","Text":"actually are small molecules similar to the one"},{"Start":"06:22.670 ","End":"06:27.725","Text":"that I showed you at the very first figure in this video."},{"Start":"06:27.725 ","End":"06:32.052","Text":"They will go straight into the nucleus."},{"Start":"06:32.052 ","End":"06:38.450","Text":"They can transport, go right through the nucleus because they can go through membranes."},{"Start":"06:38.450 ","End":"06:42.830","Text":"Of course, they are lipid-soluble,"},{"Start":"06:42.830 ","End":"06:45.935","Text":"and then their receptor is in the nucleus, and then again,"},{"Start":"06:45.935 ","End":"06:49.925","Text":"you get the same gene expression and"},{"Start":"06:49.925 ","End":"06:55.420","Text":"cause changes in the amount of particular proteins which are made."},{"Start":"06:55.420 ","End":"07:03.199","Text":"The hormone receptor complex is the one that changes the transcription of specific genes."},{"Start":"07:03.199 ","End":"07:08.200","Text":"On the other hand, there are other kinds of hormones,"},{"Start":"07:08.200 ","End":"07:11.735","Text":"ones which cannot diffuse through the cell membrane."},{"Start":"07:11.735 ","End":"07:14.000","Text":"For instance, peptide hormones,"},{"Start":"07:14.000 ","End":"07:18.040","Text":"so they are lipid-insoluble hormones."},{"Start":"07:18.040 ","End":"07:19.940","Text":"For instance, peptides, like I said,"},{"Start":"07:19.940 ","End":"07:22.400","Text":"are amino acid-derived hormones,"},{"Start":"07:22.400 ","End":"07:29.315","Text":"and they are going to have to bind the receptor which is in the cell membrane."},{"Start":"07:29.315 ","End":"07:32.660","Text":"They bind receptors on the outer surface of"},{"Start":"07:32.660 ","End":"07:37.715","Text":"the plasma membrane and then that receptor protein changes"},{"Start":"07:37.715 ","End":"07:41.480","Text":"its conformation somehow to activate"},{"Start":"07:41.480 ","End":"07:46.500","Text":"a signal transduction pathway inside the target cell."},{"Start":"07:46.500 ","End":"07:50.960","Text":"That\u0027s what\u0027s going to change the transcription of particular genes,"},{"Start":"07:50.960 ","End":"07:54.425","Text":"either activating them or deactivating them."},{"Start":"07:54.425 ","End":"07:56.870","Text":"An example of this, by the way,"},{"Start":"07:56.870 ","End":"08:00.844","Text":"is insulin, which is a peptide hormone,"},{"Start":"08:00.844 ","End":"08:03.110","Text":"and it has a receptor,"},{"Start":"08:03.110 ","End":"08:06.920","Text":"and then there is a signal transduction pathway which changes"},{"Start":"08:06.920 ","End":"08:11.350","Text":"the metabolism of the cells that the insulin interacts with."},{"Start":"08:11.350 ","End":"08:12.890","Text":"How does this happen?"},{"Start":"08:12.890 ","End":"08:16.220","Text":"There is typically a first messenger,"},{"Start":"08:16.220 ","End":"08:19.370","Text":"which is the hormone that initiates a signaling pathway."},{"Start":"08:19.370 ","End":"08:20.940","Text":"We call that the first messenger."},{"Start":"08:20.940 ","End":"08:23.465","Text":"But then there\u0027s a second messenger in the cell,"},{"Start":"08:23.465 ","End":"08:27.320","Text":"which is going to be moving to the nucleus,"},{"Start":"08:27.320 ","End":"08:30.830","Text":"and that can be all sorts of things as we\u0027ll see."},{"Start":"08:30.830 ","End":"08:32.960","Text":"Now an advantage of this system is that"},{"Start":"08:32.960 ","End":"08:38.080","Text":"the second messenger can be and usually is quite short lived."},{"Start":"08:38.080 ","End":"08:42.965","Text":"That allows for a very quick response in"},{"Start":"08:42.965 ","End":"08:48.275","Text":"the cell to changes in the peptide hormone that\u0027s outside."},{"Start":"08:48.275 ","End":"08:52.970","Text":"So elevated concentration of the second messenger leads to rapid alteration in"},{"Start":"08:52.970 ","End":"08:58.130","Text":"the activity of either 1 or more cellular enzymes."},{"Start":"08:58.130 ","End":"09:01.475","Text":"That\u0027s a way of amplifying the signal also."},{"Start":"09:01.475 ","End":"09:03.520","Text":"The removal or degradation of"},{"Start":"09:03.520 ","End":"09:06.510","Text":"the second messenger then terminates the cellular response,"},{"Start":"09:06.510 ","End":"09:10.420","Text":"so we can have a rapid on and a rapid off"},{"Start":"09:10.420 ","End":"09:15.695","Text":"because of the short half-lives of these second messengers."},{"Start":"09:15.695 ","End":"09:18.880","Text":"There are different classes of these second messengers."},{"Start":"09:18.880 ","End":"09:24.520","Text":"They can be very small molecules like cyclic nucleotides,"},{"Start":"09:24.520 ","End":"09:26.290","Text":"in this case, cyclic AMP,"},{"Start":"09:26.290 ","End":"09:28.069","Text":"for instance, as an example in this figure."},{"Start":"09:28.069 ","End":"09:30.325","Text":"It\u0027s a cyclic nucleotide."},{"Start":"09:30.325 ","End":"09:36.395","Text":"They can be even very small molecules like calcium or nitric acid."},{"Start":"09:36.395 ","End":"09:39.965","Text":"They can be a bit bigger membrane lipid-derivatives."},{"Start":"09:39.965 ","End":"09:45.290","Text":"In any case, they can be all sorts of things, these second messengers."},{"Start":"09:45.290 ","End":"09:49.640","Text":"Now the response of the cell to these depends"},{"Start":"09:49.640 ","End":"09:54.170","Text":"on the type of receptors that are present on the target cell,"},{"Start":"09:54.170 ","End":"10:01.515","Text":"and they of course can change membrane permeability,"},{"Start":"10:01.515 ","End":"10:04.505","Text":"they could stimulate synthesis of proteins and enzymes,"},{"Start":"10:04.505 ","End":"10:10.740","Text":"and they can activate the release of other hormones."}],"ID":30225}],"Thumbnail":null,"ID":286912},{"Name":"Regulation of Body Processes","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Regulation of Blood Osmolarity","Duration":"8m 18s","ChapterTopicVideoID":28709,"CourseChapterTopicPlaylistID":286913,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.200 ","End":"00:02.595","Text":"I\u0027m glad you\u0027re back."},{"Start":"00:02.595 ","End":"00:06.915","Text":"We now know what hormones are in a general sense."},{"Start":"00:06.915 ","End":"00:09.510","Text":"In the following several videos,"},{"Start":"00:09.510 ","End":"00:16.245","Text":"we\u0027re going to be dealing with the regulation of body processes by hormones."},{"Start":"00:16.245 ","End":"00:20.100","Text":"We\u0027ll be discussing the regulation of the hormones"},{"Start":"00:20.100 ","End":"00:24.810","Text":"that affects various systems like the excretory system,"},{"Start":"00:24.810 ","End":"00:26.765","Text":"like the reproductive system,"},{"Start":"00:26.765 ","End":"00:28.790","Text":"how they affect metabolism,"},{"Start":"00:28.790 ","End":"00:32.240","Text":"blood calcium concentrations, growth, and stress response."},{"Start":"00:32.240 ","End":"00:39.105","Text":"All of these things are going to require coordination of different organs."},{"Start":"00:39.105 ","End":"00:45.005","Text":"Therefore, they are very good for having hormones controlling them."},{"Start":"00:45.005 ","End":"00:49.640","Text":"The water concentration in blood,"},{"Start":"00:49.640 ","End":"00:55.370","Text":"for instance, is monitored by receptors called osmoreceptors."},{"Start":"00:55.370 ","End":"00:58.900","Text":"Receptors that measure osmotic pressure."},{"Start":"00:58.900 ","End":"01:02.465","Text":"These receptors are in the hypothalamus in the brain,"},{"Start":"01:02.465 ","End":"01:06.935","Text":"and they essentially detect the concentration of electrolytes."},{"Start":"01:06.935 ","End":"01:08.850","Text":"Electrolytes are various salts,"},{"Start":"01:08.850 ","End":"01:12.430","Text":"primarily salts in the extracellular fluid."},{"Start":"01:12.430 ","End":"01:17.825","Text":"Now, we know that electrolyte concentration in the blood rises,"},{"Start":"01:17.825 ","End":"01:24.515","Text":"it will go up the concentration of salts will rise when the water intake is low,"},{"Start":"01:24.515 ","End":"01:27.495","Text":"or when we lose blood."},{"Start":"01:27.495 ","End":"01:31.325","Text":"Yes. There\u0027s going to have to be some a balance"},{"Start":"01:31.325 ","End":"01:36.080","Text":"in the body between the fluids and the electrolytes in"},{"Start":"01:36.080 ","End":"01:38.620","Text":"order to maintain proper pH"},{"Start":"01:38.620 ","End":"01:41.660","Text":"and certainly be able to carry"},{"Start":"01:41.660 ","End":"01:44.870","Text":"electrical signals from nerves to the muscles at a minimum."},{"Start":"01:44.870 ","End":"01:50.345","Text":"We\u0027ve got all different kinds of salts that we\u0027ve spoken about before."},{"Start":"01:50.345 ","End":"01:52.640","Text":"Sodium, chlorine, magnesium, calcium,"},{"Start":"01:52.640 ","End":"01:54.035","Text":"potassium, and so on."},{"Start":"01:54.035 ","End":"01:59.155","Text":"Of course, all of these are affected by the foods that we eat."},{"Start":"01:59.155 ","End":"02:03.470","Text":"When electrolyte levels increase,"},{"Start":"02:03.470 ","End":"02:09.557","Text":"then the osmoreceptors will send a signal to the hypothalamic nuclei,"},{"Start":"02:09.557 ","End":"02:15.890","Text":"and the hypothalamus in turn produces a hormone called ADH,"},{"Start":"02:15.890 ","End":"02:23.045","Text":"antidiuretic hormone ADH, which was released from the pituitary gland."},{"Start":"02:23.045 ","End":"02:26.980","Text":"Yes, which is also in the brain from the posterior pituitary brand."},{"Start":"02:26.980 ","End":"02:33.650","Text":"The hypothalamus is going to be producing a hormone that at"},{"Start":"02:33.650 ","End":"02:40.340","Text":"the end of the day is going to be controlling the osmotic pressure in the bloodstream."},{"Start":"02:40.340 ","End":"02:42.820","Text":"Now, let\u0027s see how that is done."},{"Start":"02:42.820 ","End":"02:48.845","Text":"The ADH, which by the way is also called vasopressin in some places,"},{"Start":"02:48.845 ","End":"02:50.955","Text":"but we\u0027re going to call it ADH here."},{"Start":"02:50.955 ","End":"02:53.420","Text":"The ADH hormone, yes,"},{"Start":"02:53.420 ","End":"02:55.900","Text":"is produced in the hypothalamus, as we said,"},{"Start":"02:55.900 ","End":"03:03.040","Text":"and it\u0027s secreted to the bloodstream through the posterior pituitary gland."},{"Start":"03:03.040 ","End":"03:06.080","Text":"Here we can see the hypothalamus,"},{"Start":"03:06.080 ","End":"03:12.080","Text":"and the posterior pituitary which is secreting ADH,"},{"Start":"03:12.080 ","End":"03:14.285","Text":"goes into the bloodstream."},{"Start":"03:14.285 ","End":"03:17.720","Text":"What does it do? It is sensed by"},{"Start":"03:17.720 ","End":"03:23.375","Text":"the kidney and it promotes reabsorption of water in the kidney."},{"Start":"03:23.375 ","End":"03:27.650","Text":"When there\u0027s water which has gone into these green tubes,"},{"Start":"03:27.650 ","End":"03:33.310","Text":"which are the tubes that are eventually going to be connected to the bladder."},{"Start":"03:33.310 ","End":"03:39.770","Text":"Inside the kidney, if there\u0027s not enough water in the blood,"},{"Start":"03:39.770 ","End":"03:42.830","Text":"then they can be reabsorption of water back in"},{"Start":"03:42.830 ","End":"03:47.765","Text":"the opposite direction to be able to maintain the proper water balance."},{"Start":"03:47.765 ","End":"03:54.815","Text":"It\u0027s the hypothalamus now that is going to control how much of the ADH is secreted,"},{"Start":"03:54.815 ","End":"03:58.790","Text":"either by regulating the blood volume and"},{"Start":"03:58.790 ","End":"04:03.155","Text":"that can happen by changing the amount of water that\u0027s there,"},{"Start":"04:03.155 ","End":"04:05.405","Text":"or the concentration of water in the blood."},{"Start":"04:05.405 ","End":"04:10.690","Text":"There are various ways of doing this and we\u0027ll see the future how this can be done."},{"Start":"04:10.690 ","End":"04:17.120","Text":"The increase in blood osmolarity above 300 milli Osm per liter,"},{"Start":"04:17.120 ","End":"04:22.050","Text":"raises the ADH secretion and consequently water retention."},{"Start":"04:22.050 ","End":"04:25.220","Text":"This will increase blood pressure,"},{"Start":"04:25.220 ","End":"04:31.090","Text":"so you could see the normal osmolarity and when the blood osmolarity increases,"},{"Start":"04:31.090 ","End":"04:34.220","Text":"if we\u0027ve lost some water by sweating profusely,"},{"Start":"04:34.220 ","End":"04:36.440","Text":"there are different things that can cause this."},{"Start":"04:36.440 ","End":"04:43.065","Text":"Then the hypothalamus will go into action producing ADH, causing water reabsorption."},{"Start":"04:43.065 ","End":"04:51.710","Text":"We\u0027re talking here about excretion essentially and how that\u0027s regulated by the ADH."},{"Start":"04:51.710 ","End":"04:55.130","Text":"This is called now the ADH effect."},{"Start":"04:55.130 ","End":"05:01.925","Text":"How does it work? We\u0027re now asking what happens in the kidney."},{"Start":"05:01.925 ","End":"05:03.605","Text":"What happens in the kidney?"},{"Start":"05:03.605 ","End":"05:06.460","Text":"This is just an enlargement of the tube and the kidney,"},{"Start":"05:06.460 ","End":"05:09.425","Text":"so here\u0027s the tube,"},{"Start":"05:09.425 ","End":"05:11.420","Text":"the collecting duct that\u0027s inside"},{"Start":"05:11.420 ","End":"05:16.385","Text":"the kidney and on this side would be the water in the blood."},{"Start":"05:16.385 ","End":"05:20.480","Text":"What happens is that ADH increases the number of aquaporins,"},{"Start":"05:20.480 ","End":"05:24.470","Text":"that\u0027s water channels in the kidney tubules, so that happens."},{"Start":"05:24.470 ","End":"05:32.015","Text":"Here\u0027s the ADH, which through a signal transduction pathway creates more water channels."},{"Start":"05:32.015 ","End":"05:35.435","Text":"That then allows the water to go,"},{"Start":"05:35.435 ","End":"05:41.870","Text":"or it forces water really to go from inside the duct,"},{"Start":"05:41.870 ","End":"05:44.885","Text":"the collecting duct in the kidney back into the bloodstream."},{"Start":"05:44.885 ","End":"05:49.115","Text":"ADH can be the water to be reabsorbed into the capillaries,"},{"Start":"05:49.115 ","End":"05:52.985","Text":"lowering blood osmolarity back to normal."},{"Start":"05:52.985 ","End":"05:54.635","Text":"Now in some cases,"},{"Start":"05:54.635 ","End":"05:59.480","Text":"ADH is reduced by certain substances abuse,"},{"Start":"05:59.480 ","End":"06:02.330","Text":"usually like alcohol, which can cause"},{"Start":"06:02.330 ","End":"06:05.645","Text":"increased urine production, and therefore dehydration."},{"Start":"06:05.645 ","End":"06:08.720","Text":"If you drink a lot of alcohol,"},{"Start":"06:08.720 ","End":"06:15.570","Text":"you make cause yourself actually to become dehydrated and that can be dangerous."},{"Start":"06:16.180 ","End":"06:25.160","Text":"In diabetes, we have a chronic underproduction of ADH, chronic underproduction ADH."},{"Start":"06:25.160 ","End":"06:29.495","Text":"Or there\u0027s a possibility that there\u0027s a mutation in the ADH receptor."},{"Start":"06:29.495 ","End":"06:31.735","Text":"The ADH is made,"},{"Start":"06:31.735 ","End":"06:35.760","Text":"but it\u0027s not sensed because there\u0027s no receptor."},{"Start":"06:35.760 ","End":"06:37.820","Text":"As a result, water cannot be retained in"},{"Start":"06:37.820 ","End":"06:41.615","Text":"the kidneys and we have an increase in the amount of urine."},{"Start":"06:41.615 ","End":"06:44.150","Text":"Here\u0027s a diabetes and here\u0027s the normal,"},{"Start":"06:44.150 ","End":"06:47.070","Text":"so we\u0027ll have more urine produced and of course,"},{"Start":"06:47.070 ","End":"06:48.620","Text":"just as we mentioned before,"},{"Start":"06:48.620 ","End":"06:51.350","Text":"that can cause dehydration."},{"Start":"06:51.350 ","End":"06:59.900","Text":"One last thing in this subject will be to look at another hormone called aldosterone."},{"Start":"06:59.900 ","End":"07:04.610","Text":"It\u0027s a steroid hormone and the class will see these later,"},{"Start":"07:04.610 ","End":"07:10.990","Text":"called mineralocorticoid that\u0027s produced now by the adrenal cortex."},{"Start":"07:10.990 ","End":"07:14.830","Text":"It\u0027s also responsible for maintaining electrolyte concentrations"},{"Start":"07:14.830 ","End":"07:19.000","Text":"in the extracellular fluids by moving not water,"},{"Start":"07:19.000 ","End":"07:20.380","Text":"but as we\u0027ll see,"},{"Start":"07:20.380 ","End":"07:23.170","Text":"moving sodium and potassium,"},{"Start":"07:23.170 ","End":"07:28.885","Text":"it\u0027s enhances sodium reabsorption and potassium secretion in the kidney tubules."},{"Start":"07:28.885 ","End":"07:30.835","Text":"Similar to what we saw with the water,"},{"Start":"07:30.835 ","End":"07:36.010","Text":"but in the opposite direction and that results in the osmotic reabsorption of water."},{"Start":"07:36.010 ","End":"07:42.610","Text":"We can see here that the aldosterone combines with a cytoplasmic receptor."},{"Start":"07:42.610 ","End":"07:47.043","Text":"Then we have a signal transduction pathway"},{"Start":"07:47.043 ","End":"07:51.720","Text":"that\u0027s occurs here that causes the transcription of"},{"Start":"07:51.720 ","End":"07:56.705","Text":"particular messenger RNAs to create new channels"},{"Start":"07:56.705 ","End":"08:03.035","Text":"that will move potassium and sodium in the appropriate directions,"},{"Start":"08:03.035 ","End":"08:09.245","Text":"so as to result in increased sodium reabsorption,"},{"Start":"08:09.245 ","End":"08:13.385","Text":"and potassium secretion returning cells back to normal,"},{"Start":"08:13.385 ","End":"08:18.810","Text":"and that is what we see here in this last statement."}],"ID":30237},{"Watched":false,"Name":"Regulation of the Reproductive System","Duration":"7m 13s","ChapterTopicVideoID":28706,"CourseChapterTopicPlaylistID":286913,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.787","Text":"The next system that we want to talk about,"},{"Start":"00:03.787 ","End":"00:06.127","Text":"which is regulated by hormones,"},{"Start":"00:06.127 ","End":"00:08.239","Text":"is the reproductive system."},{"Start":"00:08.239 ","End":"00:13.665","Text":"As you know, it\u0027s considerably more complicated than you might expect,"},{"Start":"00:13.665 ","End":"00:18.602","Text":"and it\u0027s controlled by all hormones from the pituitary gland,"},{"Start":"00:18.602 ","End":"00:21.590","Text":"the adrenal cortex, and the gonads."},{"Start":"00:21.590 ","End":"00:28.921","Text":"These hormones control the sexual development in both sexes as well, of course,"},{"Start":"00:28.921 ","End":"00:31.579","Text":"as the menstrual cycle,"},{"Start":"00:31.579 ","End":"00:39.015","Text":"and it controls what happens in a woman\u0027s body during pregnancy and then breastfeeding."},{"Start":"00:39.015 ","End":"00:46.525","Text":"Let\u0027s delve into this a little bit and try to understand how hormones are involved."},{"Start":"00:46.525 ","End":"00:49.250","Text":"During puberty in both genders,"},{"Start":"00:49.250 ","End":"00:56.345","Text":"the hypothalamus produces a hormone called gonadotropin-releasing hormone, or GNRH."},{"Start":"00:56.345 ","End":"00:58.670","Text":"Here\u0027s a GNRH in the pituitary,"},{"Start":"00:58.670 ","End":"01:04.770","Text":"and it then stimulates the production of 2 different hormones,"},{"Start":"01:04.770 ","End":"01:06.695","Text":"one is called LH,"},{"Start":"01:06.695 ","End":"01:09.515","Text":"and the other one is called FSH."},{"Start":"01:09.515 ","End":"01:13.040","Text":"In both males and females, as we\u0027ll see,"},{"Start":"01:13.040 ","End":"01:16.655","Text":"they\u0027re involved in gamete production,"},{"Start":"01:16.655 ","End":"01:19.300","Text":"of course it\u0027s going to be a little bit different."},{"Start":"01:19.300 ","End":"01:21.195","Text":"These hormones now,"},{"Start":"01:21.195 ","End":"01:27.100","Text":"are released actually from the anterior pituitary gland."},{"Start":"01:27.100 ","End":"01:31.445","Text":"As I said, stimulates gamete production,"},{"Start":"01:31.445 ","End":"01:36.335","Text":"and the FSH produced stimulates gametes production,"},{"Start":"01:36.335 ","End":"01:43.025","Text":"and the LH will still stimulates production of hormones by the gonads."},{"Start":"01:43.025 ","End":"01:51.815","Text":"However, the GNRH production is subject to a feedback inhibition loop."},{"Start":"01:51.815 ","End":"01:55.550","Text":"Yes, it\u0027s inhibited by the gonad hormone levels through"},{"Start":"01:55.550 ","End":"02:01.270","Text":"this negative feedback loop so that not too much of it is produced."},{"Start":"02:01.270 ","End":"02:04.775","Text":"Now, let\u0027s start out by looking at males."},{"Start":"02:04.775 ","End":"02:07.265","Text":"In the male reproductive system,"},{"Start":"02:07.265 ","End":"02:11.360","Text":"FSH stimulates the maturation of sperm,"},{"Start":"02:11.360 ","End":"02:14.390","Text":"so there are sperm which are in the testes,"},{"Start":"02:14.390 ","End":"02:17.569","Text":"which are not yet mature,"},{"Start":"02:17.569 ","End":"02:20.330","Text":"and the FSH stimulates that,"},{"Start":"02:20.330 ","End":"02:22.010","Text":"but we don\u0027t want too much,"},{"Start":"02:22.010 ","End":"02:26.360","Text":"so there is another hormone called inhibin,"},{"Start":"02:26.360 ","End":"02:30.425","Text":"which inhibits the production of FSH,"},{"Start":"02:30.425 ","End":"02:38.090","Text":"so there is a feedback mechanism here controlling the rate at which sperm are produced."},{"Start":"02:38.090 ","End":"02:45.110","Text":"Now, LH is interstitial cell-stimulating hormone."},{"Start":"02:45.110 ","End":"02:50.420","Text":"That means that it\u0027s between cells, this hormone, yes,"},{"Start":"02:50.420 ","End":"02:54.229","Text":"and it stimulates the production of the sex hormones,"},{"Start":"02:54.229 ","End":"02:58.490","Text":"we\u0027ll see that this is a case of females as well that are called androgens,"},{"Start":"02:58.490 ","End":"03:00.950","Text":"androgens are sex hormones."},{"Start":"03:00.950 ","End":"03:05.570","Text":"For instance, testosterone by the cells,"},{"Start":"03:05.570 ","End":"03:08.030","Text":"interstitial cells of the testes,"},{"Start":"03:08.030 ","End":"03:11.525","Text":"those are particular cells that are between other cells,"},{"Start":"03:11.525 ","End":"03:17.155","Text":"and of course, testosterone is the androgen,"},{"Start":"03:17.155 ","End":"03:18.975","Text":"it\u0027s most widely known,"},{"Start":"03:18.975 ","End":"03:22.330","Text":"and it promotes the production of sperm,"},{"Start":"03:22.880 ","End":"03:25.335","Text":"and in addition to that,"},{"Start":"03:25.335 ","End":"03:29.870","Text":"it causes the production of various masculine characteristics."},{"Start":"03:29.870 ","End":"03:35.735","Text":"Now, the adrenal cortex also produces small amounts of a testosterone precursor,"},{"Start":"03:35.735 ","End":"03:40.615","Text":"but we\u0027re not really sure exactly what that does."},{"Start":"03:40.615 ","End":"03:48.455","Text":"Now, in females we also have LH and FSH,"},{"Start":"03:48.455 ","End":"03:54.575","Text":"and we also have a form of inhibin doing a similar thing as it did in the males,"},{"Start":"03:54.575 ","End":"03:55.940","Text":"but of course,"},{"Start":"03:55.940 ","End":"03:58.835","Text":"this stimulation is a bit different."},{"Start":"03:58.835 ","End":"04:05.205","Text":"FSH stimulates the egg cell to develop in a follicle,"},{"Start":"04:05.205 ","End":"04:11.615","Text":"and it produces the same inhibin hormone that we saw before for this feedback regulation."},{"Start":"04:11.615 ","End":"04:16.355","Text":"Now, LH is produced as well, and in females,"},{"Start":"04:16.355 ","End":"04:21.860","Text":"it induces ovulation and stimulates estradiol and progesterone."},{"Start":"04:21.860 ","End":"04:26.705","Text":"Those are 2 additional hormones, and what do they do?"},{"Start":"04:26.705 ","End":"04:31.910","Text":"Estradiol and progesterone are steroid hormones that prepare"},{"Start":"04:31.910 ","End":"04:39.360","Text":"the body now for pregnancy during each of the menstrual cycles."},{"Start":"04:39.830 ","End":"04:42.530","Text":"In addition to this,"},{"Start":"04:42.530 ","End":"04:45.185","Text":"once pregnancy is achieved,"},{"Start":"04:45.185 ","End":"04:48.965","Text":"then there is prolactin."},{"Start":"04:48.965 ","End":"04:52.965","Text":"Prolactin or sometimes lactotropin,"},{"Start":"04:52.965 ","End":"04:54.680","Text":"which is produced, and what is that?"},{"Start":"04:54.680 ","End":"05:01.520","Text":"That\u0027s going to have to do with the connection between the development of the breast,"},{"Start":"05:01.520 ","End":"05:06.560","Text":"and production of milk and relating it to the rest of the system."},{"Start":"05:06.560 ","End":"05:11.525","Text":"This hormone actually is very versatile and it has"},{"Start":"05:11.525 ","End":"05:18.530","Text":"some function in over 300 different processes in various animals."},{"Start":"05:18.530 ","End":"05:20.135","Text":"But one of the things that it does,"},{"Start":"05:20.135 ","End":"05:21.470","Text":"or one of the main things that it does,"},{"Start":"05:21.470 ","End":"05:26.505","Text":"is it stimulates milk production by the memory glands following birth,"},{"Start":"05:26.505 ","End":"05:34.115","Text":"and it is regulated now by another hormone called prolactin releasing hormone,"},{"Start":"05:34.115 ","End":"05:36.995","Text":"the PRH and prolactin inhibiting hormone."},{"Start":"05:36.995 ","End":"05:46.785","Text":"Here as well, we have a feedback kind of mechanism on the production of the prolactin,"},{"Start":"05:46.785 ","End":"05:50.265","Text":"you can see that over here in the pituitary."},{"Start":"05:50.265 ","End":"05:55.369","Text":"Prolactin admission that is increase in prolactin"},{"Start":"05:55.369 ","End":"06:00.275","Text":"causes the production of breast milk if you put it in from the outside,"},{"Start":"06:00.275 ","End":"06:05.840","Text":"even in men and in women who are not pregnant or breastfeeding."},{"Start":"06:05.840 ","End":"06:10.280","Text":"Finally, there\u0027s another hormone called oxytocin,"},{"Start":"06:10.280 ","End":"06:19.610","Text":"which is released from the posterior pituitary,"},{"Start":"06:19.610 ","End":"06:23.015","Text":"and it stimulates uterine contractions during childbirth"},{"Start":"06:23.015 ","End":"06:27.335","Text":"via a positive feedback mechanism that you can see,"},{"Start":"06:27.335 ","End":"06:28.470","Text":"described over here,"},{"Start":"06:28.470 ","End":"06:33.650","Text":"and it stimulates the contraction around milk-producing cells as"},{"Start":"06:33.650 ","End":"06:39.225","Text":"well in the mammary glands so that milk is ejected."},{"Start":"06:39.225 ","End":"06:41.070","Text":"This is towards the baby,"},{"Start":"06:41.070 ","End":"06:43.680","Text":"it\u0027s called this let-down reflex,"},{"Start":"06:43.680 ","End":"06:47.390","Text":"and it\u0027s controlled by a positive feedback mechanism that is"},{"Start":"06:47.390 ","End":"06:51.850","Text":"stimulated when the baby tries to suckle."},{"Start":"06:51.850 ","End":"06:55.460","Text":"Interestingly, this connection between"},{"Start":"06:55.460 ","End":"06:59.495","Text":"the mother and the child is also an emotional one,"},{"Start":"06:59.495 ","End":"07:03.990","Text":"which is hormonally regulated by oxytocin,"},{"Start":"07:03.990 ","End":"07:06.620","Text":"and it\u0027s associated with empathy,"},{"Start":"07:06.620 ","End":"07:13.230","Text":"with trust, some sexual activity, and relationship building."}],"ID":30234},{"Watched":false,"Name":"Regulation of the Blood Sugar Levels","Duration":"9m 23s","ChapterTopicVideoID":28705,"CourseChapterTopicPlaylistID":286913,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.240","Text":"I\u0027m glad you\u0027re back now to continue"},{"Start":"00:03.240 ","End":"00:07.425","Text":"our discussion of regulation of body processes via hormones."},{"Start":"00:07.425 ","End":"00:12.030","Text":"And now we\u0027re going talk about hormonal regulation of metabolism,"},{"Start":"00:12.030 ","End":"00:20.140","Text":"in which we\u0027re going to concentrate primarily on glucose in the blood."},{"Start":"00:21.410 ","End":"00:27.240","Text":"As we\u0027ll see, blood glucose levels vary widely over the course"},{"Start":"00:27.240 ","End":"00:32.265","Text":"of a day because some of the time we\u0027re eating and some of the time we\u0027re not,"},{"Start":"00:32.265 ","End":"00:40.485","Text":"and so the body somehow has to regulate how much glucose there is inside the cells,"},{"Start":"00:40.485 ","End":"00:46.250","Text":"and more importantly, it has to regulate how much glucose there is in the blood."},{"Start":"00:46.250 ","End":"00:54.065","Text":"That is done by a balance between 2 hormones, insulin and glucagon."},{"Start":"00:54.065 ","End":"00:55.910","Text":"Surely you\u0027ve heard of insulin,"},{"Start":"00:55.910 ","End":"00:57.620","Text":"but there\u0027s also glucagon."},{"Start":"00:57.620 ","End":"01:00.575","Text":"These are 2 hormones that are responsible for maintaining"},{"Start":"01:00.575 ","End":"01:04.955","Text":"homeostasis of the blood glucose levels."},{"Start":"01:04.955 ","End":"01:11.250","Text":"As you\u0027ll see, insulin is something which is made by the pancreas,"},{"Start":"01:11.250 ","End":"01:12.940","Text":"it\u0027s released by the pancreas,"},{"Start":"01:12.940 ","End":"01:19.219","Text":"and it\u0027s responsible for lowering blood glucose."},{"Start":"01:19.219 ","End":"01:25.670","Text":"On the other hand, glucagon is also released by other cells of"},{"Start":"01:25.670 ","End":"01:32.750","Text":"the pancreas and it stimulates the liver to release glucose into the blood."},{"Start":"01:32.750 ","End":"01:37.580","Text":"The level of glucose in the blood will go up as response to glucagon,"},{"Start":"01:37.580 ","End":"01:42.450","Text":"whereas it will go down in response to insulin."},{"Start":"01:42.620 ","End":"01:46.640","Text":"These are the 2 primary hormones,"},{"Start":"01:46.640 ","End":"01:49.280","Text":"but there is some additional regulation that\u0027s"},{"Start":"01:49.280 ","End":"01:53.930","Text":"mediated by the thyroid hormones as we\u0027ll see later."},{"Start":"01:53.930 ","End":"01:58.970","Text":"How does this work? Insulin is produced by the pancreas,"},{"Start":"01:58.970 ","End":"02:01.415","Text":"as we said in Beta cells that are in the pancreas,"},{"Start":"02:01.415 ","End":"02:05.810","Text":"and what they do is they have target cells,"},{"Start":"02:05.810 ","End":"02:09.985","Text":"for instance, these adipocytes that is fat cells."},{"Start":"02:09.985 ","End":"02:16.440","Text":"Insulin is produced by Beta cells in the pancreas and it affects various target cells,"},{"Start":"02:16.440 ","End":"02:19.305","Text":"so for instance, these adipocytes,"},{"Start":"02:19.305 ","End":"02:22.400","Text":"that\u0027s fat cells or muscle."},{"Start":"02:22.400 ","End":"02:30.185","Text":"In each case, the blood glucose levels then are lowered because these target organs,"},{"Start":"02:30.185 ","End":"02:36.885","Text":"for instance, the adipocytes or the muscles then are stimulated to take up glucose."},{"Start":"02:36.885 ","End":"02:41.930","Text":"Glucose then leaves the blood vessel is taken up by the cells,"},{"Start":"02:41.930 ","End":"02:45.800","Text":"and so glucose uptake is increased by"},{"Start":"02:45.800 ","End":"02:50.195","Text":"the insulin and it\u0027s utilized by these target cells."},{"Start":"02:50.195 ","End":"02:56.600","Text":"In additional way that insulin affects blood glucose levels is"},{"Start":"02:56.600 ","End":"03:04.385","Text":"by influencing the liver to change glucose into glycogen."},{"Start":"03:04.385 ","End":"03:09.270","Text":"Glycogen is a storage molecule that is kept in the liver,"},{"Start":"03:09.270 ","End":"03:10.595","Text":"and as we\u0027ll see later,"},{"Start":"03:10.595 ","End":"03:12.620","Text":"glucagon is going to do the opposite."},{"Start":"03:12.620 ","End":"03:17.225","Text":"It\u0027s going to change glucagon into glucose."},{"Start":"03:17.225 ","End":"03:20.570","Text":"But for now, what we\u0027re looking at is how insulin"},{"Start":"03:20.570 ","End":"03:25.235","Text":"stimulates the liver to convert glucose to glucagon and it\u0027s stored."},{"Start":"03:25.235 ","End":"03:30.770","Text":"In addition, the insulin increases glucose transport into certain cells,"},{"Start":"03:30.770 ","End":"03:32.225","Text":"like the muscle cells,"},{"Start":"03:32.225 ","End":"03:35.120","Text":"as we mentioned earlier."},{"Start":"03:35.120 ","End":"03:42.365","Text":"Now, let\u0027s look at insulin in greater detail and see how it acts."},{"Start":"03:42.365 ","End":"03:45.170","Text":"What it actually does is it increases the number of"},{"Start":"03:45.170 ","End":"03:50.280","Text":"glucose transporter proteins called GLUT in cell membranes."},{"Start":"03:50.280 ","End":"03:56.300","Text":"The insulin, when it interacts with a proper receptor through"},{"Start":"03:56.300 ","End":"04:04.340","Text":"a signal transduction pathway increases the number of these GLUT transporters,"},{"Start":"04:04.340 ","End":"04:08.990","Text":"and that allows glucose to enter the cell more efficiently."},{"Start":"04:08.990 ","End":"04:11.855","Text":"Were of course it\u0027s used as an energy source."},{"Start":"04:11.855 ","End":"04:13.670","Text":"There are some exceptions to this."},{"Start":"04:13.670 ","End":"04:17.240","Text":"For instance, the kidneys and the brain cells don\u0027t"},{"Start":"04:17.240 ","End":"04:21.125","Text":"require insulin in order to get access to glucose."},{"Start":"04:21.125 ","End":"04:23.960","Text":"But in any case, what the insulin does is it"},{"Start":"04:23.960 ","End":"04:27.770","Text":"stimulates the conversion of glucose to fat in adipocytes,"},{"Start":"04:27.770 ","End":"04:30.360","Text":"additional storage facility,"},{"Start":"04:30.360 ","End":"04:34.925","Text":"and in addition, the synthesis of proteins."},{"Start":"04:34.925 ","End":"04:38.225","Text":"Finally, when there\u0027s too much insulin around"},{"Start":"04:38.225 ","End":"04:42.155","Text":"and the level of glucose in the blood goes back to normal,"},{"Start":"04:42.155 ","End":"04:49.235","Text":"there is a negative feedback loop which keeps the insulin from being released further."},{"Start":"04:49.235 ","End":"04:53.555","Text":"Now, as you all know, there\u0027s a disease called diabetes."},{"Start":"04:53.555 ","End":"05:00.185","Text":"Diabetes, of course insulin doesn\u0027t work as it should or there isn\u0027t any insulin."},{"Start":"05:00.185 ","End":"05:03.260","Text":"Actually, there are 2 different types."},{"Start":"05:03.260 ","End":"05:07.130","Text":"There is 1 type of diabetes in"},{"Start":"05:07.130 ","End":"05:10.895","Text":"which there are low levels of insulin production by the Beta cells."},{"Start":"05:10.895 ","End":"05:12.395","Text":"This you can see over here,"},{"Start":"05:12.395 ","End":"05:14.960","Text":"the Beta cells are not producing any insulin,"},{"Start":"05:14.960 ","End":"05:17.914","Text":"therefore they\u0027re not interacting with the receptor."},{"Start":"05:17.914 ","End":"05:25.445","Text":"And therefore the target cells"},{"Start":"05:25.445 ","End":"05:28.580","Text":"cannot change the number of GLUT receptors."},{"Start":"05:28.580 ","End":"05:30.420","Text":"In the other type of diabetes,"},{"Start":"05:30.420 ","End":"05:33.665","Text":"Type II, there is plenty of insulin around."},{"Start":"05:33.665 ","End":"05:37.080","Text":"The problem is that the receptor has been changed such"},{"Start":"05:37.080 ","End":"05:42.380","Text":"that it is no longer receptive to the insulin,"},{"Start":"05:42.380 ","End":"05:47.520","Text":"or it might be that it has a lower sensitivity to insulin."},{"Start":"05:47.520 ","End":"05:49.805","Text":"Therefore for the same reason,"},{"Start":"05:49.805 ","End":"05:54.410","Text":"the cells don\u0027t respond to insulin, and again,"},{"Start":"05:54.410 ","End":"05:57.235","Text":"we don\u0027t have the larger number of"},{"Start":"05:57.235 ","End":"06:01.705","Text":"GLUT receptors and the glucose stays outside of the cell."},{"Start":"06:01.705 ","End":"06:05.285","Text":"This prevents at the end of the day glucose transfer,"},{"Start":"06:05.285 ","End":"06:07.775","Text":"causing what\u0027s called hyperglycemia."},{"Start":"06:07.775 ","End":"06:10.355","Text":"Glycemia has to do with sugar levels,"},{"Start":"06:10.355 ","End":"06:16.645","Text":"hyper is too much high levels of blood, glucose is hyperglycemia."},{"Start":"06:16.645 ","End":"06:18.900","Text":"Now what does this cause?"},{"Start":"06:18.900 ","End":"06:21.620","Text":"It causes dry mouth, increased thirst,"},{"Start":"06:21.620 ","End":"06:24.754","Text":"weakness, headache, blurred vision, frequent urination."},{"Start":"06:24.754 ","End":"06:28.650","Text":"It makes it difficult for the kidneys to recover all the glucose,"},{"Start":"06:28.650 ","End":"06:31.305","Text":"and therefore there\u0027s this urination,"},{"Start":"06:31.305 ","End":"06:34.250","Text":"and the less water absorbed by the kidney causes"},{"Start":"06:34.250 ","End":"06:39.590","Text":"a high volume of urine and dehydration as we said."},{"Start":"06:39.590 ","End":"06:42.590","Text":"Over time, there can be"},{"Start":"06:42.590 ","End":"06:46.490","Text":"nerve damage that is caused both in the eyes and peripheral bodies."},{"Start":"06:46.490 ","End":"06:50.179","Text":"You know, sometimes people get amputations because"},{"Start":"06:50.179 ","End":"06:54.410","Text":"of diabetes because there\u0027s not good blood flow damage to the kidneys,"},{"Start":"06:54.410 ","End":"06:56.270","Text":"it\u0027s not a good thing."},{"Start":"06:56.270 ","End":"07:04.595","Text":"On the other hand, insulin can be over secreted and that causes hypoglycemia."},{"Start":"07:04.595 ","End":"07:08.940","Text":"Hypo is low blood glucose level,"},{"Start":"07:08.940 ","End":"07:10.490","Text":"and what does that cause?"},{"Start":"07:10.490 ","End":"07:12.455","Text":"The symptoms would be sweating, pallor,"},{"Start":"07:12.455 ","End":"07:15.155","Text":"irritability, hunger, lack of coordination, sleepiness."},{"Start":"07:15.155 ","End":"07:18.755","Text":"Of course, there\u0027s not enough glucose in the blood,"},{"Start":"07:18.755 ","End":"07:24.490","Text":"not enough energy, and therefore the body is not behaving well."},{"Start":"07:24.490 ","End":"07:27.840","Text":"This can cause, of course, the hypoglycemia,"},{"Start":"07:27.840 ","End":"07:31.505","Text":"there not to be sufficient glucose available to the cells,"},{"Start":"07:31.505 ","End":"07:34.655","Text":"and we have these various symptoms that we\u0027ve mentioned."},{"Start":"07:34.655 ","End":"07:37.580","Text":"If it\u0027s too bad,"},{"Start":"07:37.580 ","End":"07:40.640","Text":"the blood sugar is too low,"},{"Start":"07:40.640 ","End":"07:44.945","Text":"then we can get unconsciousness or even death."},{"Start":"07:44.945 ","End":"07:48.680","Text":"Now the other side of the coin is regulation of"},{"Start":"07:48.680 ","End":"07:52.810","Text":"blood glucose by the other hormone called glucagon."},{"Start":"07:52.810 ","End":"08:01.040","Text":"As we mentioned, it stimulates the breakdown of glycogen in the liver into glucose."},{"Start":"08:01.040 ","End":"08:03.680","Text":"It\u0027s the opposite of what the insulin did."},{"Start":"08:03.680 ","End":"08:05.480","Text":"Remember in insulin,"},{"Start":"08:05.480 ","End":"08:08.420","Text":"we had glucose being turned into glucagon in the liver."},{"Start":"08:08.420 ","End":"08:10.100","Text":"It stimulated the liver to do that,"},{"Start":"08:10.100 ","End":"08:12.170","Text":"glucagon does the opposite."},{"Start":"08:12.170 ","End":"08:15.790","Text":"Glucose is produced from glycogen,"},{"Start":"08:15.790 ","End":"08:21.920","Text":"so it stimulates the breakdown of glycogen to glucose in the liver,"},{"Start":"08:21.920 ","End":"08:25.520","Text":"but also in skeletal muscle."},{"Start":"08:25.520 ","End":"08:31.460","Text":"It also stimulates the absorption of amino acids from the blood by the liver."},{"Start":"08:31.460 ","End":"08:33.020","Text":"This is something that we haven\u0027t mentioned before."},{"Start":"08:33.020 ","End":"08:36.950","Text":"There is a biochemical pathway which allows amino acids to be"},{"Start":"08:36.950 ","End":"08:42.310","Text":"converted to glucose in a process called gluconeogenesis."},{"Start":"08:42.310 ","End":"08:47.035","Text":"Genesis means making something from scratch, new."},{"Start":"08:47.035 ","End":"08:50.330","Text":"Glucagon also stimulates adipose cells and"},{"Start":"08:50.330 ","End":"08:53.645","Text":"fat cells to release fatty acids into the blood,"},{"Start":"08:53.645 ","End":"08:57.080","Text":"where they also make"},{"Start":"08:57.080 ","End":"09:03.445","Text":"new blood glucose and hopefully get it back to normal homeostatic levels."},{"Start":"09:03.445 ","End":"09:09.110","Text":"Of course, this rising blood glucose levels inhibits further glucagon release."},{"Start":"09:09.110 ","End":"09:12.160","Text":"Again, there\u0027s a negative feedback mechanism,"},{"Start":"09:12.160 ","End":"09:13.820","Text":"so just like in the case of insulin,"},{"Start":"09:13.820 ","End":"09:15.305","Text":"we don\u0027t have too much produced."},{"Start":"09:15.305 ","End":"09:18.770","Text":"This negative feedback mechanism makes sure that there is"},{"Start":"09:18.770 ","End":"09:23.250","Text":"not too much glucagon produced either."}],"ID":30233},{"Watched":false,"Name":"Regulation of Metabolism by the Thyroid","Duration":"9m 6s","ChapterTopicVideoID":28711,"CourseChapterTopicPlaylistID":286913,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:01.950","Text":"Now in this video,"},{"Start":"00:01.950 ","End":"00:06.105","Text":"we\u0027re going to continue our discussion of regulation of body processes by"},{"Start":"00:06.105 ","End":"00:11.505","Text":"looking at the thyroid and the parathyroid."},{"Start":"00:11.505 ","End":"00:14.580","Text":"The thyroid gland, as you can see,"},{"Start":"00:14.580 ","End":"00:16.575","Text":"which is in the neck,"},{"Start":"00:16.575 ","End":"00:18.510","Text":"and the parathyroid,"},{"Start":"00:18.510 ","End":"00:20.865","Text":"which will be attached to it."},{"Start":"00:20.865 ","End":"00:23.085","Text":"Now, what does it do?"},{"Start":"00:23.085 ","End":"00:24.840","Text":"It has several functions."},{"Start":"00:24.840 ","End":"00:30.720","Text":"But one of the major things it does is it controls the basic metabolic rate, the BMR."},{"Start":"00:30.720 ","End":"00:34.320","Text":"There\u0027s the number of calories required by the body at"},{"Start":"00:34.320 ","End":"00:39.180","Text":"rest so that when body needs more energy,"},{"Start":"00:39.180 ","End":"00:43.025","Text":"then or the temperature needs to be regulated."},{"Start":"00:43.025 ","End":"00:48.290","Text":"Then this can be done via 2 hormones that are produced by the thyroid gland."},{"Start":"00:48.290 ","End":"00:50.900","Text":"One is thyroxine,"},{"Start":"00:50.900 ","End":"01:00.100","Text":"which is sometimes called T_4 for tetraiodothyronine or triiodothyronine."},{"Start":"01:00.100 ","End":"01:01.940","Text":"These are basically the same,"},{"Start":"01:01.940 ","End":"01:04.010","Text":"very much the same molecule,"},{"Start":"01:04.010 ","End":"01:12.495","Text":"but one of them has 3 iodine atoms in it and the other has 4, T_3 and T_4."},{"Start":"01:12.495 ","End":"01:16.460","Text":"They\u0027re stimulated these hormones by TSH,"},{"Start":"01:16.460 ","End":"01:21.095","Text":"the thyroid-stimulating hormone which is produced."},{"Start":"01:21.095 ","End":"01:26.950","Text":"Here\u0027s the TSH which has produced by the anterior pituitary gland."},{"Start":"01:26.950 ","End":"01:31.780","Text":"T_3 and T_4 affect almost every cell in the body."},{"Start":"01:31.780 ","End":"01:33.530","Text":"With the exception of brain, uterus,"},{"Start":"01:33.530 ","End":"01:35.555","Text":"testes, blood cells, and spleen."},{"Start":"01:35.555 ","End":"01:40.580","Text":"Because if the temperature of the body has to be controlled then the"},{"Start":"01:40.580 ","End":"01:46.250","Text":"metabolism of pretty much all the cells in the body need to be changed."},{"Start":"01:46.250 ","End":"01:48.125","Text":"Now how does it do that?"},{"Start":"01:48.125 ","End":"01:52.640","Text":"The T_3 and the T_4 bind receptors on mitochondria,"},{"Start":"01:52.640 ","End":"01:56.285","Text":"which remember the powerhouses in cells."},{"Start":"01:56.285 ","End":"02:02.334","Text":"They result then in increased ATP production."},{"Start":"02:02.334 ","End":"02:06.350","Text":"They also in the nucleus of the cell activate genes that are"},{"Start":"02:06.350 ","End":"02:10.010","Text":"involved in energy production and glucose oxidation,"},{"Start":"02:10.010 ","End":"02:15.050","Text":"resulting in something called the calorigenic effect."},{"Start":"02:15.050 ","End":"02:17.195","Text":"Making more calories."},{"Start":"02:17.195 ","End":"02:22.475","Text":"So increased rates of metabolism by the T_3,"},{"Start":"02:22.475 ","End":"02:32.179","Text":"T_4 hormones that are produced when the thyroid gland sees TSH produced by the pituitary."},{"Start":"02:32.179 ","End":"02:36.725","Text":"Now, let\u0027s look in more detail about how these T_3 and"},{"Start":"02:36.725 ","End":"02:42.815","Text":"T_4 hormones are made and how they take up iodine."},{"Start":"02:42.815 ","End":"02:46.400","Text":"There\u0027s a precursor called thyroglobulin."},{"Start":"02:46.400 ","End":"02:50.150","Text":"It\u0027s a glycoprotein and it\u0027s present in the thyroid and is"},{"Start":"02:50.150 ","End":"02:54.620","Text":"converted into these thyroid hormones by the addition of iodine."},{"Start":"02:54.620 ","End":"02:59.210","Text":"Iodine is first trapped from the bloodstream."},{"Start":"02:59.210 ","End":"03:02.480","Text":"It goes into the cells that are in the thyroid."},{"Start":"03:02.480 ","End":"03:08.240","Text":"Actually, it\u0027s been oxidized from iodide into iodine,"},{"Start":"03:08.240 ","End":"03:17.350","Text":"which is then coupled to tyrosines that are found on the thyroglobulin."},{"Start":"03:17.350 ","End":"03:20.565","Text":"This is what\u0027s explained over here,"},{"Start":"03:20.565 ","End":"03:25.249","Text":"the iodide is what\u0027s found in the bloodstream."},{"Start":"03:25.249 ","End":"03:29.945","Text":"Then there\u0027s approximate enzyme that does this attachment of iodine."},{"Start":"03:29.945 ","End":"03:39.530","Text":"They are then released into the bloodstream when there\u0027s a movement of this protein,"},{"Start":"03:39.530 ","End":"03:44.530","Text":"this proteolysis, and finally released into the bloodstream."},{"Start":"03:44.530 ","End":"03:52.399","Text":"There is a dysfunction of the thyroid called goiter when the thyroid becomes enlarged."},{"Start":"03:52.399 ","End":"03:54.385","Text":"What\u0027s that all about?"},{"Start":"03:54.385 ","End":"03:56.805","Text":"The thyroid follicles,"},{"Start":"03:56.805 ","End":"04:00.440","Text":"each of these follicles is made up of a central cavity"},{"Start":"04:00.440 ","End":"04:05.105","Text":"inside each of them that has this very sticky colloidal fluid inside."},{"Start":"04:05.105 ","End":"04:08.895","Text":"That\u0027s where the thyroglobulin is."},{"Start":"04:08.895 ","End":"04:14.585","Text":"As we know, TSH stimulates higher levels of colloid accumulation,"},{"Start":"04:14.585 ","End":"04:19.390","Text":"and this can also occur if we have goiter."},{"Start":"04:19.390 ","End":"04:22.625","Text":"Can occur if we have inadequate iodine intake,"},{"Start":"04:22.625 ","End":"04:25.955","Text":"then there\u0027s an inability to synthesize these hormones"},{"Start":"04:25.955 ","End":"04:29.950","Text":"and an overproduction of TSH trying to make up for this."},{"Start":"04:29.950 ","End":"04:32.090","Text":"As you can see in this figure,"},{"Start":"04:32.090 ","End":"04:37.265","Text":"the Goiter can be very pronounced and quite ugly."},{"Start":"04:37.265 ","End":"04:42.770","Text":"Now let\u0027s look at thyroid disorder in a different way."},{"Start":"04:42.770 ","End":"04:50.855","Text":"We can have either hypotyroidism or we can have hyperthyroidism."},{"Start":"04:50.855 ","End":"04:55.940","Text":"The hypothyroidism is underproduction of the thyroid hormones,"},{"Start":"04:55.940 ","End":"04:58.365","Text":"hypo production."},{"Start":"04:58.365 ","End":"04:59.540","Text":"What happens there?"},{"Start":"04:59.540 ","End":"05:01.190","Text":"We have cold intolerance,"},{"Start":"05:01.190 ","End":"05:02.630","Text":"slow heartbeat, weight gain,"},{"Start":"05:02.630 ","End":"05:08.315","Text":"constipation, all things in children that can lead to mental retardation, growth effects."},{"Start":"05:08.315 ","End":"05:11.525","Text":"Hyperthyroidism, overproduction."},{"Start":"05:11.525 ","End":"05:15.440","Text":"Overproduction that we see on the right side of this figure can"},{"Start":"05:15.440 ","End":"05:20.810","Text":"cause heat intolerance and we get all sorts of things,"},{"Start":"05:20.810 ","End":"05:22.714","Text":"of course, the goiter."},{"Start":"05:22.714 ","End":"05:25.115","Text":"As we can also have,"},{"Start":"05:25.115 ","End":"05:27.350","Text":"even with the hypothyroidism,"},{"Start":"05:27.350 ","End":"05:29.510","Text":"rapid heartbeat, weight loss,"},{"Start":"05:29.510 ","End":"05:33.095","Text":"diarrhea, menstrual periods may occur less often in women."},{"Start":"05:33.095 ","End":"05:38.940","Text":"In any case, it causes various other problems."},{"Start":"05:38.940 ","End":"05:41.855","Text":"There\u0027s a disease called Graves disease,"},{"Start":"05:41.855 ","End":"05:44.900","Text":"which is an immune system disorder that results in"},{"Start":"05:44.900 ","End":"05:48.140","Text":"the overproduction of the thyroid hormones."},{"Start":"05:48.140 ","End":"05:53.690","Text":"Finally, there\u0027s another thing that we should consider and that is what"},{"Start":"05:53.690 ","End":"06:00.890","Text":"the parathyroid glands are doing that are on the back side of the thyroid gland."},{"Start":"06:00.890 ","End":"06:06.755","Text":"The parathyroid glands produce parathyroid hormone, PTH,"},{"Start":"06:06.755 ","End":"06:09.965","Text":"and it regulates blood calcium levels,"},{"Start":"06:09.965 ","End":"06:15.950","Text":"which is of course important for generation of muscle contraction and nerve impulses."},{"Start":"06:15.950 ","End":"06:17.570","Text":"Now, as you can see,"},{"Start":"06:17.570 ","End":"06:19.760","Text":"there are various sources for calcium."},{"Start":"06:19.760 ","End":"06:21.200","Text":"They can be from the bone,"},{"Start":"06:21.200 ","End":"06:23.310","Text":"they can be reabsorption from the kidney,"},{"Start":"06:23.310 ","End":"06:27.410","Text":"they can be for absorption through the intestinal tract,"},{"Start":"06:27.410 ","End":"06:34.030","Text":"and the PTH is going to affect each of these in a different way."},{"Start":"06:34.030 ","End":"06:38.720","Text":"It\u0027s released in response to low calcium levels,"},{"Start":"06:38.720 ","End":"06:45.650","Text":"and so in doing it increases the amount of calcium released from the bones."},{"Start":"06:45.650 ","End":"06:51.125","Text":"It will do something similar by"},{"Start":"06:51.125 ","End":"06:58.420","Text":"inducing reabsorption of calcium from the kidneys."},{"Start":"06:58.520 ","End":"07:09.140","Text":"This is done via a hormone called calcitriol that is released such that the intestine"},{"Start":"07:09.140 ","End":"07:13.520","Text":"releases calcium into the bloodstream and also causes"},{"Start":"07:13.520 ","End":"07:20.120","Text":"bones to decompose somewhat letting calcium also into the bloodstream."},{"Start":"07:20.120 ","End":"07:27.199","Text":"Calcitriol is an active form of vitamin D. It increases then,"},{"Start":"07:27.199 ","End":"07:32.650","Text":"calcitriol increases the absorption of dietary calcium in the intestines."},{"Start":"07:32.650 ","End":"07:39.320","Text":"PTH is inhibited by rising blood calcium levels,"},{"Start":"07:39.320 ","End":"07:46.500","Text":"of course, because it acts in an opposing direction as calcitriol."},{"Start":"07:51.290 ","End":"07:55.129","Text":"Now, if there\u0027s a parathyroid disorder,"},{"Start":"07:55.129 ","End":"07:58.580","Text":"then we can have all disorders,"},{"Start":"07:58.580 ","End":"08:01.925","Text":"as you can see over here that affect digestive system,"},{"Start":"08:01.925 ","End":"08:06.080","Text":"musculoskeletal system, urinary system, nervous system."},{"Start":"08:06.080 ","End":"08:09.330","Text":"And we can have both hyperparathyroidism,"},{"Start":"08:09.330 ","End":"08:18.695","Text":"and we can have hypoparathyroidism and they result in different functions."},{"Start":"08:18.695 ","End":"08:23.045","Text":"Let\u0027s look for a moment at calcitonin."},{"Start":"08:23.045 ","End":"08:27.110","Text":"Calcitonin is produced by the thyroid gland,"},{"Start":"08:27.110 ","End":"08:28.580","Text":"as we mentioned before,"},{"Start":"08:28.580 ","End":"08:33.260","Text":"and it operates in opposition to the PTH, as we mentioned."},{"Start":"08:33.260 ","End":"08:36.125","Text":"It decreases blood calcium levels,"},{"Start":"08:36.125 ","End":"08:42.640","Text":"inhibiting osteoclasts that release the calcium stimulates osteoblasts."},{"Start":"08:42.640 ","End":"08:48.445","Text":"Which take up the calcium and it stimulates calcium excretion by the kidneys."},{"Start":"08:48.445 ","End":"08:51.410","Text":"This calcitonin then results in calcium"},{"Start":"08:51.410 ","End":"08:54.395","Text":"being added to the bones to promote structural integrity."},{"Start":"08:54.395 ","End":"08:58.670","Text":"It\u0027s important for calcium homeostasis in adults and in some vertebrates."},{"Start":"08:58.670 ","End":"09:01.039","Text":"But yet in unstarved humans,"},{"Start":"09:01.039 ","End":"09:05.699","Text":"it\u0027s role is, as of yet unclear."}],"ID":30239},{"Watched":false,"Name":"Regulation of Cell Division by Growth Hormone","Duration":"5m 52s","ChapterTopicVideoID":28710,"CourseChapterTopicPlaylistID":286913,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.200","Text":"Now we\u0027re going to change our direction"},{"Start":"00:04.200 ","End":"00:08.970","Text":"a little bit in our discussion of the Regulation of Body Processes."},{"Start":"00:08.970 ","End":"00:15.540","Text":"What we\u0027ll do is we\u0027ll discuss regulation of growth that is really cell division and"},{"Start":"00:15.540 ","End":"00:18.450","Text":"differentiation which is a bit different than just"},{"Start":"00:18.450 ","End":"00:22.760","Text":"regulating the amount of say sugar in our blood or calcium in our blood,"},{"Start":"00:22.760 ","End":"00:24.420","Text":"and that of course,"},{"Start":"00:24.420 ","End":"00:26.850","Text":"is regulated hormonally as well."},{"Start":"00:26.850 ","End":"00:31.575","Text":"We\u0027ll start our discussion by looking at Growth Hormone."},{"Start":"00:31.575 ","End":"00:35.775","Text":"Growth hormone, sometimes it\u0027s called somatotropin,"},{"Start":"00:35.775 ","End":"00:42.330","Text":"is a peptide hormone and it\u0027s produced by the anterior pituitary gland."},{"Start":"00:42.330 ","End":"00:46.445","Text":"We\u0027ll see a little bit later in this video how it is"},{"Start":"00:46.445 ","End":"00:52.280","Text":"regulated by 2 other hormones, somatostatin and GHRH."},{"Start":"00:52.280 ","End":"00:57.289","Text":"Any case, let\u0027s start out by discussing the growth hormone itself."},{"Start":"00:57.289 ","End":"00:59.900","Text":"It\u0027s actually something called a mitogen."},{"Start":"00:59.900 ","End":"01:04.435","Text":"A mitogen is something which induces cell division."},{"Start":"01:04.435 ","End":"01:09.560","Text":"Things that makes cells divide more quickly and the growth hormone of course,"},{"Start":"01:09.560 ","End":"01:13.325","Text":"is specific to that is seen by,"},{"Start":"01:13.325 ","End":"01:14.795","Text":"and it react in,"},{"Start":"01:14.795 ","End":"01:18.935","Text":"it is attaches to specific receptors,"},{"Start":"01:18.935 ","End":"01:21.690","Text":"in particular cell types."},{"Start":"01:21.690 ","End":"01:23.185","Text":"What it does is,"},{"Start":"01:23.185 ","End":"01:26.750","Text":"the cells that are affected by it accelerate"},{"Start":"01:26.750 ","End":"01:30.950","Text":"their rate of protein synthesis and this happens particularly in"},{"Start":"01:30.950 ","End":"01:40.335","Text":"skeletal muscle and bones and that will then change how much the body grows."},{"Start":"01:40.335 ","End":"01:43.550","Text":"There are different mechanisms for this."},{"Start":"01:43.550 ","End":"01:49.190","Text":"One is a direct mechanism of the growth hormone in which adipose tissue,"},{"Start":"01:49.190 ","End":"01:55.430","Text":"that\u0027s fat tissue is then affected such that there is"},{"Start":"01:55.430 ","End":"02:02.760","Text":"lipolysis that is the fat that\u0027s there releases sugar into the blood,"},{"Start":"02:02.760 ","End":"02:08.765","Text":"glucose sparing effects, which is the energy source from glucose to fatty acids."},{"Start":"02:08.765 ","End":"02:12.140","Text":"In other words, the glucose is not used as much,"},{"Start":"02:12.140 ","End":"02:20.015","Text":"but fatty acids that are whose source is the adipose tissue is then used by most tissues."},{"Start":"02:20.015 ","End":"02:25.550","Text":"That\u0027s what this hormone does and it stimulates the glycogen breakdown."},{"Start":"02:25.550 ","End":"02:33.110","Text":"Remember, glycogen is a storage of energy in the liver and then glucose is released into"},{"Start":"02:33.110 ","End":"02:36.560","Text":"the blood and this then makes an effect which is"},{"Start":"02:36.560 ","End":"02:41.240","Text":"called diabetogenic effect and it looks a little bit like diabetes,"},{"Start":"02:41.240 ","End":"02:44.360","Text":"although it doesn\u0027t have anything to do with the insulin and it"},{"Start":"02:44.360 ","End":"02:47.705","Text":"increases blood glucose levels and therefore,"},{"Start":"02:47.705 ","End":"02:54.880","Text":"tissues are now using fatty acids for energy rather than the glucose."},{"Start":"02:54.880 ","End":"02:57.140","Text":"That\u0027s the direct mechanism,"},{"Start":"02:57.140 ","End":"03:01.820","Text":"but there\u0027s an indirect mechanism that the growth hormone works as well."},{"Start":"03:01.820 ","End":"03:04.625","Text":"And there, what do we see?"},{"Start":"03:04.625 ","End":"03:07.850","Text":"Then, insulin-like growth factors,"},{"Start":"03:07.850 ","End":"03:12.480","Text":"which are called IGFs or somatomedins."},{"Start":"03:12.550 ","End":"03:17.630","Text":"Those are peptide hormones which stimulate tissue growth."},{"Start":"03:17.630 ","End":"03:24.290","Text":"The growth hormone is going to affect these IGFs and they"},{"Start":"03:24.290 ","End":"03:26.300","Text":"are secreted primarily by"},{"Start":"03:26.300 ","End":"03:31.145","Text":"the liver as a result of stimulation by growth hormone as we said."},{"Start":"03:31.145 ","End":"03:38.810","Text":"There are several of them and they stimulate the formation of new proteins and growth,"},{"Start":"03:38.810 ","End":"03:41.210","Text":"therefore, of muscle cells,"},{"Start":"03:41.210 ","End":"03:44.060","Text":"cartilage cells, as well as other cells."},{"Start":"03:44.060 ","End":"03:49.220","Text":"Those are indirect effects as opposed to the direct effects on the adipose tissue."},{"Start":"03:49.220 ","End":"03:52.340","Text":"Now as we said, there\u0027s more than one IGF."},{"Start":"03:52.340 ","End":"03:59.885","Text":"There\u0027s a major one which is an adult that\u0027s called IGF-1 and there\u0027s 1 called IGF- 2,"},{"Start":"03:59.885 ","End":"04:03.680","Text":"which works in the fetus before birth."},{"Start":"04:03.680 ","End":"04:12.480","Text":"We mentioned earlier that growth hormone is regulated by 2 different other hormones."},{"Start":"04:12.480 ","End":"04:17.105","Text":"One was GHRH and the other was somatostatin,"},{"Start":"04:17.105 ","End":"04:20.180","Text":"and they work in opposite directions,"},{"Start":"04:20.180 ","End":"04:24.155","Text":"a positive effect and a negative effect."},{"Start":"04:24.155 ","End":"04:28.820","Text":"GHRH stands for growth hormone-releasing hormone,"},{"Start":"04:28.820 ","End":"04:34.400","Text":"and it stimulates the anterior pituitary to"},{"Start":"04:34.400 ","End":"04:40.870","Text":"release growth hormone and the opposite of that is the GHIH,"},{"Start":"04:40.870 ","End":"04:46.865","Text":"which is sometimes called somatostatin and it inhibits growth hormone released."},{"Start":"04:46.865 ","End":"04:50.570","Text":"It\u0027s the balance of these 2 which is"},{"Start":"04:50.570 ","End":"04:53.500","Text":"critical to get the appropriate development"},{"Start":"04:53.500 ","End":"04:55.865","Text":"because if you don\u0027t have the appropriate development,"},{"Start":"04:55.865 ","End":"05:00.860","Text":"then what you end up with is either giantism or dwarfism."},{"Start":"05:00.860 ","End":"05:04.909","Text":"The person becomes too large or too small."},{"Start":"05:04.909 ","End":"05:10.220","Text":"Pituitary dwarfism is caused by under secretion of the growth hormone during"},{"Start":"05:10.220 ","End":"05:16.685","Text":"childhood but it does not appear to be any bad or abnormalities,"},{"Start":"05:16.685 ","End":"05:18.590","Text":"just a child is much smaller."},{"Start":"05:18.590 ","End":"05:20.740","Text":"On the other hand, there\u0027s giantism."},{"Start":"05:20.740 ","End":"05:24.860","Text":"People can reach heights of even over 8 feet and"},{"Start":"05:24.860 ","End":"05:29.330","Text":"that\u0027s caused by over secretion of growth hormone during childhood."},{"Start":"05:29.330 ","End":"05:35.015","Text":"In addition, there are some deformalities called acromegaly,"},{"Start":"05:35.015 ","End":"05:39.560","Text":"which is the enlargement of bones that are still capable of growth in the face,"},{"Start":"05:39.560 ","End":"05:43.310","Text":"hands, and feet during adulthood so you get a little bit of"},{"Start":"05:43.310 ","End":"05:51.910","Text":"disproportionate size of the extremities in some of these smaller people."}],"ID":30238},{"Watched":false,"Name":"Regulation of Blood Calcium levels by the Parathyroid","Duration":"7m 26s","ChapterTopicVideoID":28708,"CourseChapterTopicPlaylistID":286913,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.915","Text":"I\u0027m glad you\u0027re back to our continuing discussion of the regulation of body processes."},{"Start":"00:06.915 ","End":"00:11.745","Text":"In our previous video, we were talking about the thyroid gland"},{"Start":"00:11.745 ","End":"00:16.335","Text":"that produces the different thyroid hormones."},{"Start":"00:16.335 ","End":"00:19.455","Text":"We\u0027ll be talking about the parathyroid hormone,"},{"Start":"00:19.455 ","End":"00:23.400","Text":"which is produced by parathyroid glands."},{"Start":"00:23.400 ","End":"00:28.800","Text":"Now those are little glands about the size of a pea that are on the thyroid itself."},{"Start":"00:28.800 ","End":"00:30.710","Text":"Of course, we\u0027re still talking about the neck."},{"Start":"00:30.710 ","End":"00:35.030","Text":"If you remember, the hormones produced by the thyroid that we"},{"Start":"00:35.030 ","End":"00:39.995","Text":"discussed were those that affected blood glucose levels."},{"Start":"00:39.995 ","End":"00:43.010","Text":"In this case, we\u0027re going to be talking about"},{"Start":"00:43.010 ","End":"00:48.770","Text":"blood calcium levels that are regulated by the parathyroid hormone."},{"Start":"00:48.770 ","End":"00:54.335","Text":"We\u0027ll be discussing calcium levels that are in the bloodstream."},{"Start":"00:54.335 ","End":"00:55.780","Text":"Now how does that happen?"},{"Start":"00:55.780 ","End":"01:03.410","Text":"Remember that calcium is involved in muscle contraction and of course in nerve impulses."},{"Start":"01:03.410 ","End":"01:06.080","Text":"So it\u0027s very important that the level of"},{"Start":"01:06.080 ","End":"01:10.355","Text":"calcium in the blood be very carefully regulated."},{"Start":"01:10.355 ","End":"01:17.090","Text":"PTH is released in response to low blood calcium levels."},{"Start":"01:17.090 ","End":"01:19.400","Text":"When the calcium is low,"},{"Start":"01:19.400 ","End":"01:21.028","Text":"PTH is released,"},{"Start":"01:21.028 ","End":"01:25.130","Text":"and the effect of that will be an increase in calcium in the blood."},{"Start":"01:25.130 ","End":"01:28.640","Text":"Now, where is the calcium going to come from?"},{"Start":"01:28.640 ","End":"01:33.349","Text":"Well, we\u0027ll find out that it comes from different sources, the kidneys,"},{"Start":"01:33.349 ","End":"01:36.740","Text":"the bones, increased absorption from the intestine,"},{"Start":"01:36.740 ","End":"01:38.705","Text":"and we\u0027ll see how that happens."},{"Start":"01:38.705 ","End":"01:43.820","Text":"PTH is going to target these various organs,"},{"Start":"01:43.820 ","End":"01:45.845","Text":"the skeleton or the bones,"},{"Start":"01:45.845 ","End":"01:47.879","Text":"and the kidneys and the intestine,"},{"Start":"01:47.879 ","End":"01:51.755","Text":"and it will do different things in different places."},{"Start":"01:51.755 ","End":"01:57.215","Text":"The kidneys are directly affected by the PTH."},{"Start":"01:57.215 ","End":"02:00.215","Text":"But the effect on the intestines,"},{"Start":"02:00.215 ","End":"02:03.620","Text":"we will see is not direct as it is in the kidneys."},{"Start":"02:03.620 ","End":"02:06.500","Text":"It\u0027s a little bit indirect through"},{"Start":"02:06.500 ","End":"02:10.915","Text":"another hormone called calcitriol. How does that happen?"},{"Start":"02:10.915 ","End":"02:13.835","Text":"PTH triggers the formation of calcitriol,"},{"Start":"02:13.835 ","End":"02:16.985","Text":"which actually is a small molecule."},{"Start":"02:16.985 ","End":"02:22.000","Text":"It\u0027s an active form of the vitamin D. Now,"},{"Start":"02:22.000 ","End":"02:25.610","Text":"of course, vitamin D, we can get either directly from our food,"},{"Start":"02:25.610 ","End":"02:27.650","Text":"we can eat it as pills to supplement."},{"Start":"02:27.650 ","End":"02:32.225","Text":"Our body can make it in the skin in response to sunlight."},{"Start":"02:32.225 ","End":"02:35.285","Text":"That vitamin D then is processed through the liver,"},{"Start":"02:35.285 ","End":"02:38.855","Text":"and makes this calcidiol."},{"Start":"02:38.855 ","End":"02:43.255","Text":"The PTH is going to trigger that"},{"Start":"02:43.255 ","End":"02:48.440","Text":"production of calcidiol and the calcidiol then is going to"},{"Start":"02:48.440 ","End":"02:52.910","Text":"affect both the absorption in the calcium in"},{"Start":"02:52.910 ","End":"02:59.375","Text":"the intestine and the release of calcium by the bone, as we\u0027ll see."},{"Start":"02:59.375 ","End":"03:03.635","Text":"It increases absorption of dietary calcium in the intestine,"},{"Start":"03:03.635 ","End":"03:11.105","Text":"and its release is inhibited now by rising blood calcium levels,"},{"Start":"03:11.105 ","End":"03:14.870","Text":"so there is a feedback mechanism which will"},{"Start":"03:14.870 ","End":"03:19.765","Text":"regulate the amount of PTH in the bloodstream."},{"Start":"03:19.765 ","End":"03:24.070","Text":"Now, there are parathyroid disorders,"},{"Start":"03:24.070 ","End":"03:30.550","Text":"just as there are thyroid disorders and they as well come in 2 flavors."},{"Start":"03:30.550 ","End":"03:34.030","Text":"Either there is hyperparathyroidism,"},{"Start":"03:34.030 ","End":"03:38.665","Text":"that\u0027s overproduction of PTH or hypoparathyroidism,"},{"Start":"03:38.665 ","End":"03:41.535","Text":"underproduction of PTH,"},{"Start":"03:41.535 ","End":"03:46.070","Text":"and of course, they have opposing effects."},{"Start":"03:46.070 ","End":"03:50.530","Text":"Hyperparathyroidism results in excessive calcium"},{"Start":"03:50.530 ","End":"03:54.220","Text":"being removed from the bones and introduced into the blood circulation,"},{"Start":"03:54.220 ","End":"04:02.943","Text":"and in hypothyroidism, there are extremely low levels of blood calcium,"},{"Start":"04:02.943 ","End":"04:07.835","Text":"and that can cause muscle not to work properly,"},{"Start":"04:07.835 ","End":"04:13.310","Text":"and the same thing can go with problems with the nervous system."},{"Start":"04:13.310 ","End":"04:19.580","Text":"There is another hormone that is involved in calcium levels in the blood that"},{"Start":"04:19.580 ","End":"04:28.395","Text":"works in an opposed way to the PTH that we saw earlier."},{"Start":"04:28.395 ","End":"04:32.950","Text":"It\u0027s called calcitonin and"},{"Start":"04:33.290 ","End":"04:39.530","Text":"it is made by the thyroid gland as well as the other hormones,"},{"Start":"04:39.530 ","End":"04:44.470","Text":"the T_3 and T_4 that we saw earlier."},{"Start":"04:44.470 ","End":"04:47.705","Text":"The calcitonin is produced by the thyroid gland."},{"Start":"04:47.705 ","End":"04:53.690","Text":"It opposes PTH and its function is to decrease blood calcium levels."},{"Start":"04:53.690 ","End":"04:55.100","Text":"How does it do that?"},{"Start":"04:55.100 ","End":"04:57.740","Text":"It inhibits osteoclasts."},{"Start":"04:57.740 ","End":"05:04.820","Text":"Those are the cells that are in the bones themselves from releasing calcium."},{"Start":"05:04.820 ","End":"05:07.510","Text":"It stimulates the osteoblasts,"},{"Start":"05:07.510 ","End":"05:09.545","Text":"which are the cells that are going to become"},{"Start":"05:09.545 ","End":"05:13.415","Text":"osteoclasts and it stimulates calcium excretion"},{"Start":"05:13.415 ","End":"05:20.400","Text":"by the kidneys so that there will be less calcium in the bloodstream, of course."},{"Start":"05:20.400 ","End":"05:24.770","Text":"Calcitonin then results in calcium being added to"},{"Start":"05:24.770 ","End":"05:28.730","Text":"the bones to promote structural integrity of the bones and of course,"},{"Start":"05:28.730 ","End":"05:37.010","Text":"it\u0027s important for calcium homeostasis as it works in opposition to the PTH."},{"Start":"05:37.010 ","End":"05:42.335","Text":"A final way of regulating the osmolarity of the blood"},{"Start":"05:42.335 ","End":"05:48.710","Text":"is a system called the renin-angiotensin-aldosterone system,"},{"Start":"05:48.710 ","End":"05:53.370","Text":"or the RAAS and it works like this."},{"Start":"05:53.370 ","End":"05:57.470","Text":"When the blood pressure falls, then the kidneys,"},{"Start":"05:57.470 ","End":"05:59.825","Text":"so here\u0027s a piece of the kidney,"},{"Start":"05:59.825 ","End":"06:01.685","Text":"releases an enzyme,"},{"Start":"06:01.685 ","End":"06:12.190","Text":"renin into the bloodstream where it meets up with a molecule called angiotensinogen."},{"Start":"06:12.190 ","End":"06:15.515","Text":"That\u0027s a protein which is produced by the liver."},{"Start":"06:15.515 ","End":"06:17.960","Text":"The renin is an enzyme, as I said,"},{"Start":"06:17.960 ","End":"06:22.580","Text":"it\u0027s a protease which will cleave"},{"Start":"06:22.580 ","End":"06:29.490","Text":"the angiotensinogen into angiotensin I, as you can see."},{"Start":"06:29.490 ","End":"06:31.380","Text":"Then in the lungs,"},{"Start":"06:31.380 ","End":"06:32.805","Text":"of course, it\u0027s in the bloodstream,"},{"Start":"06:32.805 ","End":"06:38.150","Text":"so it now will reach the lungs and it is converted to angiotensin II."},{"Start":"06:38.150 ","End":"06:40.085","Text":"Now, what does that cause?"},{"Start":"06:40.085 ","End":"06:44.455","Text":"The angiotensin II is sensed by"},{"Start":"06:44.455 ","End":"06:50.420","Text":"the adrenal gland and it causes the release of aldosterone,"},{"Start":"06:50.420 ","End":"06:51.770","Text":"as we saw earlier,"},{"Start":"06:51.770 ","End":"06:53.570","Text":"resulting in water retention,"},{"Start":"06:53.570 ","End":"06:54.965","Text":"an increase in blood pressure."},{"Start":"06:54.965 ","End":"06:58.160","Text":"It also causes arterioles,"},{"Start":"06:58.160 ","End":"07:05.240","Text":"that\u0027s the small blood vessels and the small sacs that are in our lungs"},{"Start":"07:05.240 ","End":"07:12.400","Text":"to constrict and that causes an increase in ADH as well,"},{"Start":"07:12.400 ","End":"07:16.550","Text":"and it causes increased thirst and those things"},{"Start":"07:16.550 ","End":"07:21.980","Text":"will increase the blood pressure so that will cause again,"},{"Start":"07:21.980 ","End":"07:25.290","Text":"normal blood pressure and volume."}],"ID":30236},{"Watched":false,"Name":"Stress Response Regulation","Duration":"5m 31s","ChapterTopicVideoID":28707,"CourseChapterTopicPlaylistID":286913,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.739","Text":"Welcome back to our discussion of Regulation of Body Processes."},{"Start":"00:04.739 ","End":"00:07.845","Text":"This will be the last video in this section,"},{"Start":"00:07.845 ","End":"00:12.870","Text":"and we\u0027re going to be discussing the Hormonal Regulation of Stress."},{"Start":"00:12.870 ","End":"00:18.464","Text":"Stress, which can be either short-term or long-term."},{"Start":"00:18.464 ","End":"00:25.070","Text":"In short-term, when there is a threat that is either actual or perceived,"},{"Start":"00:25.070 ","End":"00:31.010","Text":"the body replies with something called a fight-or-flight response."},{"Start":"00:31.010 ","End":"00:34.175","Text":"In other words, the body is either going to fight off"},{"Start":"00:34.175 ","End":"00:38.930","Text":"this danger or it may run away the fight-or-flight response."},{"Start":"00:38.930 ","End":"00:45.170","Text":"But in any case, each of these requires very high degree of awareness,"},{"Start":"00:45.170 ","End":"00:51.430","Text":"it may require a lot of energy that will be used all at once."},{"Start":"00:51.430 ","End":"00:58.250","Text":"This perceived danger sets off several different things."},{"Start":"00:58.250 ","End":"01:01.145","Text":"For one thing, in the hypothalamus,"},{"Start":"01:01.145 ","End":"01:08.300","Text":"there are nerve impulses that then sends signals to the adrenal medulla,"},{"Start":"01:08.300 ","End":"01:11.139","Text":"which is on top of the kidney."},{"Start":"01:11.139 ","End":"01:12.695","Text":"At the same time,"},{"Start":"01:12.695 ","End":"01:16.945","Text":"the hypothalamus in a different region,"},{"Start":"01:16.945 ","End":"01:23.165","Text":"in the anterior pituitary is going to release a hormone, ACTH,"},{"Start":"01:23.165 ","End":"01:28.925","Text":"that is also going to be sensed by the adrenal gland,"},{"Start":"01:28.925 ","End":"01:31.660","Text":"and it too will have an effect."},{"Start":"01:31.660 ","End":"01:35.705","Text":"The sympathetic nervous system on the left side of our figure here,"},{"Start":"01:35.705 ","End":"01:44.050","Text":"regulates the response by the hypothalamus and it signals a short-term response,"},{"Start":"01:44.050 ","End":"01:48.635","Text":"and the ACTH production,"},{"Start":"01:48.635 ","End":"01:53.120","Text":"which is a little bit more of a longer-term response."},{"Start":"01:53.120 ","End":"01:58.879","Text":"Let\u0027s see what happens after the ACTH is released."},{"Start":"01:58.879 ","End":"02:01.805","Text":"In the fight-or-flight response,"},{"Start":"02:01.805 ","End":"02:05.525","Text":"the ACTH is released from the pituitary we said,"},{"Start":"02:05.525 ","End":"02:07.700","Text":"influencing the adrenal glands."},{"Start":"02:07.700 ","End":"02:11.450","Text":"Then we have cortisol and adrenaline,"},{"Start":"02:11.450 ","End":"02:13.435","Text":"which are produced by the adrenal glands."},{"Start":"02:13.435 ","End":"02:18.709","Text":"They do several different things into the bloodstream."},{"Start":"02:18.709 ","End":"02:25.470","Text":"For one thing, it increases the amount of sugar that there is in the blood."},{"Start":"02:25.910 ","End":"02:30.690","Text":"For another, it raises high blood pressure,"},{"Start":"02:30.690 ","End":"02:32.685","Text":"it slows down digestion,"},{"Start":"02:32.685 ","End":"02:34.545","Text":"makes tunnel vision,"},{"Start":"02:34.545 ","End":"02:36.255","Text":"heart rate is accelerated,"},{"Start":"02:36.255 ","End":"02:38.525","Text":"fast breathing, increased sweating,"},{"Start":"02:38.525 ","End":"02:40.250","Text":"increased blood pressure, as we said."},{"Start":"02:40.250 ","End":"02:41.930","Text":"Then in addition to that,"},{"Start":"02:41.930 ","End":"02:45.860","Text":"glycogen in the liver is converted to glucose,"},{"Start":"02:45.860 ","End":"02:49.160","Text":"so we have a more of a supply of glucose in the blood,"},{"Start":"02:49.160 ","End":"02:51.035","Text":"higher amount of glucose in the blood,"},{"Start":"02:51.035 ","End":"02:54.664","Text":"so that energy can be expanded."},{"Start":"02:54.664 ","End":"02:58.980","Text":"However, this is not good for the very long term."},{"Start":"02:58.980 ","End":"03:01.110","Text":"They could be, for instance,"},{"Start":"03:01.110 ","End":"03:03.620","Text":"they could occur during an illness."},{"Start":"03:03.620 ","End":"03:09.480","Text":"There\u0027s only a certain amount that can come from the glycogen in the liver."},{"Start":"03:09.480 ","End":"03:12.200","Text":"There is an additional solution to this,"},{"Start":"03:12.200 ","End":"03:19.780","Text":"which is glucocorticoids are hormones that ensure long-term energy requirements."},{"Start":"03:19.780 ","End":"03:22.375","Text":"What do they do? They mobilize lipid,"},{"Start":"03:22.375 ","End":"03:25.685","Text":"protein reserves, stimulate gluconeogenesis."},{"Start":"03:25.685 ","End":"03:28.730","Text":"They can serve glucose so that it can be used by"},{"Start":"03:28.730 ","End":"03:33.185","Text":"neural tissue and they stimulate the conservation of salts and water."},{"Start":"03:33.185 ","End":"03:36.470","Text":"All of those things are going to be necessary to have"},{"Start":"03:36.470 ","End":"03:43.410","Text":"the heightened response to the long-term threat that is coming from the outside,"},{"Start":"03:43.410 ","End":"03:45.065","Text":"that could be, for instance,"},{"Start":"03:45.065 ","End":"03:47.975","Text":"an illness or it could be an injury that\u0027s coming from the outside."},{"Start":"03:47.975 ","End":"03:53.810","Text":"Now, the glucocorticoids, what do they do?"},{"Start":"03:53.810 ","End":"03:59.750","Text":"They affect glucose metabolism by stimulating glucose synthesis gluconeogenesis,"},{"Start":"03:59.750 ","End":"04:01.760","Text":"as we said before, but they also have"},{"Start":"04:01.760 ","End":"04:07.010","Text":"anti-inflammatory properties by inhibiting the immune system."},{"Start":"04:07.010 ","End":"04:10.430","Text":"Now it\u0027s also uses a medication, cortisone, for instance,"},{"Start":"04:10.430 ","End":"04:12.305","Text":"is using anti-inflammatory,"},{"Start":"04:12.305 ","End":"04:16.910","Text":"and there are other kinds of glucocorticoids."},{"Start":"04:16.910 ","End":"04:19.205","Text":"For instance, mineralocorticoids,"},{"Start":"04:19.205 ","End":"04:22.310","Text":"which regulate iron and water balance in the body,"},{"Start":"04:22.310 ","End":"04:24.530","Text":"and those, for instance,"},{"Start":"04:24.530 ","End":"04:29.120","Text":"can be used to cause the reabsorption of water and sodium ions in the kidney,"},{"Start":"04:29.120 ","End":"04:30.920","Text":"and things which may be necessary,"},{"Start":"04:30.920 ","End":"04:32.150","Text":"in emergency also,"},{"Start":"04:32.150 ","End":"04:38.120","Text":"and this is what increases results in the increased blood pressure and volume."},{"Start":"04:38.120 ","End":"04:39.875","Text":"Now like in anything else,"},{"Start":"04:39.875 ","End":"04:42.050","Text":"there can be abnormalities."},{"Start":"04:42.050 ","End":"04:45.470","Text":"If they\u0027re abnormalities of glucocorticoid secretion,"},{"Start":"04:45.470 ","End":"04:51.095","Text":"then we can have either hypersecretion or hyposecretion."},{"Start":"04:51.095 ","End":"04:57.020","Text":"Hypersecretion, that\u0027s too much of it can cause something called Cushing disease."},{"Start":"04:57.020 ","End":"05:00.755","Text":"That changes the fat storage areas of the body,"},{"Start":"05:00.755 ","End":"05:04.685","Text":"as you can see here, there is too much fat here in the nape of the neck."},{"Start":"05:04.685 ","End":"05:09.575","Text":"This could cause accumulation of adipose tissue in these areas,"},{"Start":"05:09.575 ","End":"05:13.835","Text":"and this will cause excessive glucose in the blood."},{"Start":"05:13.835 ","End":"05:16.400","Text":"There can be the hyposecretion, as we said,"},{"Start":"05:16.400 ","End":"05:19.850","Text":"if there\u0027s not enough of the glucocorticoids secreted,"},{"Start":"05:19.850 ","End":"05:22.160","Text":"then you get something called Addison\u0027s disease,"},{"Start":"05:22.160 ","End":"05:23.795","Text":"which can be seen here on the right."},{"Start":"05:23.795 ","End":"05:26.690","Text":"You get something that looks like bronzing of the skin,"},{"Start":"05:26.690 ","End":"05:32.190","Text":"hypoglycemia, and low electrolyte levels in the blood."}],"ID":30235}],"Thumbnail":null,"ID":286913},{"Name":"Regulation of Hormone Production","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Negative Feedback Loops","Duration":"3m 59s","ChapterTopicVideoID":28677,"CourseChapterTopicPlaylistID":286914,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:01.575","Text":"In the previous unit,"},{"Start":"00:01.575 ","End":"00:05.250","Text":"we discussed how different hormones work."},{"Start":"00:05.250 ","End":"00:09.900","Text":"Now we\u0027re going to speak about the regulation of those hormones."},{"Start":"00:09.900 ","End":"00:16.065","Text":"In this introduction, we will review a little bit of what we\u0027ve heard about before."},{"Start":"00:16.065 ","End":"00:22.710","Text":"Hormone production release are primarily controlled by negative feedback."},{"Start":"00:22.710 ","End":"00:25.620","Text":"It\u0027s primarily controlled that way."},{"Start":"00:25.620 ","End":"00:30.405","Text":"I\u0027ll remind you that negative feedback means that"},{"Start":"00:30.405 ","End":"00:32.820","Text":"a stimulus elicits the release of"},{"Start":"00:32.820 ","End":"00:36.735","Text":"a particular substance and then once that substance reaches a certain level,"},{"Start":"00:36.735 ","End":"00:40.230","Text":"it sends another signal that stops further release of the signal."},{"Start":"00:40.230 ","End":"00:44.390","Text":"For instance, remember we learned about the levels"},{"Start":"00:44.390 ","End":"00:49.180","Text":"of glucose in the blood and how they were regulated by insulin."},{"Start":"00:49.180 ","End":"00:51.380","Text":"If we ate something, for instance,"},{"Start":"00:51.380 ","End":"00:57.410","Text":"then we would have high blood glucose and then the pancreas will secrete insulin,"},{"Start":"00:57.410 ","End":"01:02.600","Text":"the insulin then would lower indirectly,"},{"Start":"01:02.600 ","End":"01:06.335","Text":"but it would lower the amount of glucose in the blood."},{"Start":"01:06.335 ","End":"01:09.860","Text":"That\u0027s negative feedback. On the other hands."},{"Start":"01:09.860 ","End":"01:13.160","Text":"When the sugar levels would decline,"},{"Start":"01:13.160 ","End":"01:17.405","Text":"then the insulin secretion also would decline."},{"Start":"01:17.405 ","End":"01:21.515","Text":"That\u0027s a negative feedback loop."},{"Start":"01:21.515 ","End":"01:26.300","Text":"Now, these various kinds signals can happen in different ways."},{"Start":"01:26.300 ","End":"01:32.120","Text":"They can be humoral means that their regulation is done via hormones."},{"Start":"01:32.120 ","End":"01:33.290","Text":"Or as we\u0027ll see,"},{"Start":"01:33.290 ","End":"01:37.075","Text":"it can be neuronal via neurons as well."},{"Start":"01:37.075 ","End":"01:40.250","Text":"The control of hormone release in response to changes"},{"Start":"01:40.250 ","End":"01:43.865","Text":"of extracellular fluids which are often hormones,"},{"Start":"01:43.865 ","End":"01:46.310","Text":"is called humoral stimulation."},{"Start":"01:46.310 ","End":"01:48.110","Text":"We can see an example of that,"},{"Start":"01:48.110 ","End":"01:50.480","Text":"for instance, something that we learned earlier."},{"Start":"01:50.480 ","End":"01:53.420","Text":"Again, we\u0027re talking about humoral control."},{"Start":"01:53.420 ","End":"01:54.710","Text":"We learned for instance,"},{"Start":"01:54.710 ","End":"01:59.705","Text":"that calcium concentrations in the blood are controlled by"},{"Start":"01:59.705 ","End":"02:07.235","Text":"the hormone PTH that is excreted by the parathyroid glands."},{"Start":"02:07.235 ","End":"02:10.325","Text":"In low calcium levels in the blood,"},{"Start":"02:10.325 ","End":"02:15.755","Text":"the parathyroid secretes PTH and that restores the balance,"},{"Start":"02:15.755 ","End":"02:19.310","Text":"then the calcium levels rise."},{"Start":"02:19.310 ","End":"02:23.630","Text":"How does this happen? PTH, for instance, you\u0027ll remember,"},{"Start":"02:23.630 ","End":"02:27.140","Text":"can raise the calcium levels in different ways, for instance,"},{"Start":"02:27.140 ","End":"02:31.630","Text":"from the bones or from the small intestine."},{"Start":"02:31.630 ","End":"02:36.013","Text":"Another example of this hormonal stimulation,"},{"Start":"02:36.013 ","End":"02:37.160","Text":"yes can be, for instance,"},{"Start":"02:37.160 ","End":"02:41.225","Text":"the release of hormones in this case,"},{"Start":"02:41.225 ","End":"02:45.265","Text":"in this example it\u0027s coming from the hypothalamus."},{"Start":"02:45.265 ","End":"02:53.295","Text":"These hormones then can influence other glands to release other hormones."},{"Start":"02:53.295 ","End":"02:58.340","Text":"There\u0027s a chain of stimulations."},{"Start":"02:58.340 ","End":"03:03.545","Text":"In this case, for instance, you\u0027ll remember that TSH can stimulate the thyroid gland,"},{"Start":"03:03.545 ","End":"03:05.510","Text":"ACTH, the adrenal gland,"},{"Start":"03:05.510 ","End":"03:09.740","Text":"and LH and FSH, the gonads,"},{"Start":"03:09.740 ","End":"03:16.805","Text":"in particular TSH, can stimulate the thyroid gland to produce T_3 and T_4."},{"Start":"03:16.805 ","End":"03:20.705","Text":"Then as the blood concentrations of T_3 and T_4 rise,"},{"Start":"03:20.705 ","End":"03:28.080","Text":"they\u0027ll inhibit both the pituitary and the hypothalamus in a negative feedback loop."},{"Start":"03:28.080 ","End":"03:31.475","Text":"Now in addition to this hormonal stimulation,"},{"Start":"03:31.475 ","End":"03:34.310","Text":"There\u0027s also neural stimulation,"},{"Start":"03:34.310 ","End":"03:36.060","Text":"as we\u0027ve mentioned before."},{"Start":"03:36.060 ","End":"03:40.190","Text":"An example of that that we\u0027ve seen before is"},{"Start":"03:40.190 ","End":"03:46.219","Text":"also that the sympathetic nervous system can directly"},{"Start":"03:46.219 ","End":"03:51.830","Text":"stimulate the adrenal medulla to release"},{"Start":"03:51.830 ","End":"03:58.770","Text":"epinephrine and norepinephrine hormones during the fight or flight response."}],"ID":30226}],"Thumbnail":null,"ID":286914},{"Name":"Endocrine Glands","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"The Hypothalamus and Pituitary Glands","Duration":"7m 12s","ChapterTopicVideoID":28704,"CourseChapterTopicPlaylistID":286915,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.020 ","End":"00:06.780","Text":"I\u0027m glad you\u0027re back now to continue to discuss the endocrine glands,"},{"Start":"00:06.780 ","End":"00:11.340","Text":"we talked about feedback loop mechanisms in the previous video."},{"Start":"00:11.340 ","End":"00:17.985","Text":"Now, we\u0027ll look at the individual endocrine glands themselves and explain how they work."},{"Start":"00:17.985 ","End":"00:20.460","Text":"Now, both endocrine and"},{"Start":"00:20.460 ","End":"00:25.545","Text":"nervous systems use chemical signals to regulate the body\u0027s physiology."},{"Start":"00:25.545 ","End":"00:28.050","Text":"As we\u0027ll see, therefore,"},{"Start":"00:28.050 ","End":"00:37.110","Text":"there is some of the nervous system chemicals influence the endocrine system as well."},{"Start":"00:37.110 ","End":"00:40.215","Text":"Let\u0027s see how that works."},{"Start":"00:40.215 ","End":"00:44.645","Text":"We\u0027ll start by looking at the pituitary gland."},{"Start":"00:44.645 ","End":"00:47.390","Text":"The pituitary gland, where there are both neurons"},{"Start":"00:47.390 ","End":"00:51.685","Text":"and endocrine cells which are coordinated with each other."},{"Start":"00:51.685 ","End":"00:54.230","Text":"The endocrine system, we will see"},{"Start":"00:54.230 ","End":"00:58.490","Text":"releases hormones and the nervous system also releases chemicals,"},{"Start":"00:58.490 ","End":"01:03.585","Text":"neurotransmitters, or we can call them even neurohormones."},{"Start":"01:03.585 ","End":"01:07.370","Text":"Because the neurons can regulate the release of hormones,"},{"Start":"01:07.370 ","End":"01:10.010","Text":"the nervous and endocrine systems work in"},{"Start":"01:10.010 ","End":"01:13.550","Text":"a coordinated manner as we had mentioned before."},{"Start":"01:13.550 ","End":"01:16.820","Text":"In this figure, we can see"},{"Start":"01:16.820 ","End":"01:23.130","Text":"the pituitary in which there are nerves here that are shown in yellow."},{"Start":"01:23.780 ","End":"01:27.460","Text":"In addition to that, there are endocrine cells"},{"Start":"01:27.460 ","End":"01:30.880","Text":"which are also going to influence the pituitary."},{"Start":"01:30.880 ","End":"01:32.620","Text":"We will see this in a moment."},{"Start":"01:32.620 ","End":"01:37.285","Text":"But let\u0027s start out by looking at the hypothalamus."},{"Start":"01:37.285 ","End":"01:40.945","Text":"The pituitary you see is down here in the brain,"},{"Start":"01:40.945 ","End":"01:44.170","Text":"but the hypothalamus is located in"},{"Start":"01:44.170 ","End":"01:48.850","Text":"the diencephalon and it integrates both endocrine and nervous systems."},{"Start":"01:48.850 ","End":"01:50.735","Text":"Now let\u0027s see how."},{"Start":"01:50.735 ","End":"01:55.480","Text":"It receives inputs from the body and then initiates"},{"Start":"01:55.480 ","End":"02:00.505","Text":"endocrine responses to the various environmental changes that have occurred."},{"Start":"02:00.505 ","End":"02:04.940","Text":"It acts as an endocrine organ in the sense that it"},{"Start":"02:04.940 ","End":"02:10.540","Text":"synthesizes hormones and transports them along either axons,"},{"Start":"02:10.540 ","End":"02:15.245","Text":"nerve cells note into the posterior pituitary,"},{"Start":"02:15.245 ","End":"02:18.620","Text":"or it synthesizes and secretes"},{"Start":"02:18.620 ","End":"02:26.510","Text":"regulatory hormones that go into the anterior pituitary glands."},{"Start":"02:26.510 ","End":"02:33.650","Text":"Now, these are synthesized again by the hypothalamus."},{"Start":"02:33.650 ","End":"02:37.040","Text":"The anterior pituitary glands now contains"},{"Start":"02:37.040 ","End":"02:41.480","Text":"autonomic centers that control endocrine cells."},{"Start":"02:41.480 ","End":"02:46.710","Text":"We\u0027re looking at the interior pituitary."},{"Start":"02:46.710 ","End":"02:50.390","Text":"These endocrine cells, they\u0027re in the adrenal medulla"},{"Start":"02:50.390 ","End":"02:55.730","Text":"are basically under neuronal control."},{"Start":"02:55.730 ","End":"02:59.990","Text":"The pituitary gland in general that we\u0027ve just been looking at is"},{"Start":"02:59.990 ","End":"03:04.370","Text":"also called the master gland sometimes are the hypophysis."},{"Start":"03:04.370 ","End":"03:07.940","Text":"It\u0027s a very small organ located at"},{"Start":"03:07.940 ","End":"03:13.980","Text":"the base of the brain in something called the sella turcica."},{"Start":"03:14.450 ","End":"03:20.150","Text":"It\u0027s attached to the hypothalamus via a particular stalk called"},{"Start":"03:20.150 ","End":"03:25.520","Text":"the pituitary stalk and as we just mentioned,"},{"Start":"03:25.520 ","End":"03:32.385","Text":"the anterior pituitary over here is regulated by hormones."},{"Start":"03:32.385 ","End":"03:37.490","Text":"By releasing inhibiting hormones that were produced by the hypothalamus,"},{"Start":"03:37.490 ","End":"03:38.720","Text":"as we mentioned before."},{"Start":"03:38.720 ","End":"03:43.760","Text":"Whereas the posterior pituitary is regulated"},{"Start":"03:43.760 ","End":"03:49.850","Text":"by neural hormones that are secreted by the axons."},{"Start":"03:49.850 ","End":"03:56.315","Text":"Now let\u0027s look at the anterior pituitary a little bit more,"},{"Start":"03:56.315 ","End":"03:58.035","Text":"in a little bit more detail."},{"Start":"03:58.035 ","End":"04:01.550","Text":"We\u0027ll see that it\u0027s surrounded by a capillary network that"},{"Start":"04:01.550 ","End":"04:05.480","Text":"carries substances from the hypothalamus to the anterior pituitary gland,"},{"Start":"04:05.480 ","End":"04:08.330","Text":"tso the things move through the bloodstream,"},{"Start":"04:08.330 ","End":"04:13.610","Text":"and hormones from the anterior pituitary then go into the circulatory system."},{"Start":"04:13.610 ","End":"04:17.555","Text":"There are no fewer than 7 different hormones."},{"Start":"04:17.555 ","End":"04:20.375","Text":"Sometimes these are called tropic hormones because"},{"Start":"04:20.375 ","End":"04:25.060","Text":"these hormones control the functioning of other organs."},{"Start":"04:25.060 ","End":"04:28.439","Text":"What are these hormones?"},{"Start":"04:28.439 ","End":"04:33.950","Text":"They are TSH, thyroid-stimulating hormone, ACTH,"},{"Start":"04:33.950 ","End":"04:37.925","Text":"which is adrenocorticotropic hormone,"},{"Start":"04:37.925 ","End":"04:41.925","Text":"ACTH, it\u0027s going to affect the adrenal glands."},{"Start":"04:41.925 ","End":"04:46.010","Text":"There\u0027s prolactin which affects mammary glands."},{"Start":"04:46.010 ","End":"04:51.215","Text":"There\u0027s MSH, melanocyte-stimulating hormones that are going to affect the skin."},{"Start":"04:51.215 ","End":"04:56.855","Text":"The ovaries are going to be affected by FSH and LH that we\u0027ll talk more about later."},{"Start":"04:56.855 ","End":"05:01.330","Text":"As the testes depending on whether we have a female or male."},{"Start":"05:01.330 ","End":"05:05.555","Text":"Even bones are affected by growth hormone,"},{"Start":"05:05.555 ","End":"05:08.300","Text":"which is produced here as well."},{"Start":"05:08.300 ","End":"05:13.355","Text":"There\u0027s a whole series of different hormones that are produced."},{"Start":"05:13.355 ","End":"05:17.000","Text":"Now we can see that the control of these hormones is"},{"Start":"05:17.000 ","End":"05:21.830","Text":"achieved by the hypothalamic releasing or inhibiting hormones."},{"Start":"05:21.830 ","End":"05:27.335","Text":"These hormones can either turn up or"},{"Start":"05:27.335 ","End":"05:33.320","Text":"turn down the activity of other hormones."},{"Start":"05:33.320 ","End":"05:42.170","Text":"Yes. For instance, somatostatin is going to negatively regulate growth hormone,"},{"Start":"05:42.170 ","End":"05:44.315","Text":"prolactin, and TSH."},{"Start":"05:44.315 ","End":"05:49.099","Text":"Whereas these other hormones like GNRH, for instance,"},{"Start":"05:49.099 ","End":"05:58.070","Text":"is going to positively affect the anterior pituitary hormones of LH and FSH."},{"Start":"05:58.070 ","End":"06:00.320","Text":"Now these regulatory hormones, as we said,"},{"Start":"06:00.320 ","End":"06:06.115","Text":"travel from the hypothalamus through this capillary network and do their job there."},{"Start":"06:06.115 ","End":"06:11.180","Text":"The negative feedback will regulate how much of the regulatory hormones are"},{"Start":"06:11.180 ","End":"06:17.645","Text":"released and how much the anterior pituitary hormone is secreted."},{"Start":"06:17.645 ","End":"06:22.745","Text":"Looking now at the posterior pituitary where the nerves are,"},{"Start":"06:22.745 ","End":"06:27.530","Text":"so extending down from the hypothalamus are the nerve fibers."},{"Start":"06:27.530 ","End":"06:33.845","Text":"They produce antidiuretic hormone, ADH,"},{"Start":"06:33.845 ","End":"06:37.955","Text":"sometimes called vasopressin and oxytocin,"},{"Start":"06:37.955 ","End":"06:42.620","Text":"which are produced again by these neurons in the hypothalamus"},{"Start":"06:42.620 ","End":"06:47.835","Text":"and they\u0027re transported that way to the posterior pituitary."},{"Start":"06:47.835 ","End":"06:51.575","Text":"Now, although they\u0027re produced in the hypothalamus,"},{"Start":"06:51.575 ","End":"06:57.365","Text":"ADH and oxytocin are often considered posterior pituitary hormones,"},{"Start":"06:57.365 ","End":"07:03.105","Text":"that\u0027s where they do their job as you can see over here."},{"Start":"07:03.105 ","End":"07:06.660","Text":"Posterior pituitary itself, however,"},{"Start":"07:06.660 ","End":"07:08.985","Text":"does not produce hormones,"},{"Start":"07:08.985 ","End":"07:12.760","Text":"the hormones go straight through."}],"ID":30232},{"Watched":false,"Name":"The Thyroid and Parathyroid Glands","Duration":"6m 44s","ChapterTopicVideoID":28701,"CourseChapterTopicPlaylistID":286915,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.575","Text":"Glad you\u0027re back to continue our discussion of endocrine glands."},{"Start":"00:04.575 ","End":"00:09.750","Text":"Now we\u0027re going to speak about the thyroid and the parathyroid,"},{"Start":"00:09.750 ","End":"00:13.980","Text":"which we\u0027ll see is a small gland that\u0027s attached to the thyroid."},{"Start":"00:13.980 ","End":"00:17.040","Text":"Now, the thyroid is located in the neck,"},{"Start":"00:17.040 ","End":"00:18.750","Text":"just below the larynx,"},{"Start":"00:18.750 ","End":"00:23.475","Text":"that\u0027s the soundbox and in front of the trachea."},{"Start":"00:23.475 ","End":"00:26.400","Text":"Trachea is a breathing tube."},{"Start":"00:26.400 ","End":"00:29.445","Text":"It has the shape of a butterfly,"},{"Start":"00:29.445 ","End":"00:32.265","Text":"as you can see here, it\u0027s a butterfly-shaped and it\u0027s got 2,"},{"Start":"00:32.265 ","End":"00:33.810","Text":"what are called lobes,"},{"Start":"00:33.810 ","End":"00:38.520","Text":"here\u0027s the 2 sides and they\u0027re connected by something called an isthmus."},{"Start":"00:38.520 ","End":"00:40.905","Text":"An isthmus is something that will connect,"},{"Start":"00:40.905 ","End":"00:43.395","Text":"say, a peninsula to the mainland."},{"Start":"00:43.395 ","End":"00:46.935","Text":"It\u0027s a connector, this isthmus."},{"Start":"00:46.935 ","End":"00:50.570","Text":"It has, that is the thyroid is has"},{"Start":"00:50.570 ","End":"00:54.275","Text":"somewhat of a dark color because it has so much blood in it,"},{"Start":"00:54.275 ","End":"00:59.450","Text":"has an extensive vascular system in it."},{"Start":"00:59.450 ","End":"01:03.965","Text":"Now, fairly often in people,"},{"Start":"01:03.965 ","End":"01:08.590","Text":"there is some dysfunction of the thyroid and then it will swell."},{"Start":"01:08.590 ","End":"01:13.565","Text":"When it swells, it can be felt under the skin in the neck."},{"Start":"01:13.565 ","End":"01:15.770","Text":"Now, let\u0027s look at its anatomy."},{"Start":"01:15.770 ","End":"01:21.125","Text":"The thyroid itself contains within it, there\u0027s an enlargement."},{"Start":"01:21.125 ","End":"01:25.400","Text":"This area contains within it many follicles,"},{"Start":"01:25.400 ","End":"01:31.790","Text":"thyroid follicles, and they are lined by a simple cuboidal epithelium."},{"Start":"01:31.790 ","End":"01:36.960","Text":"There\u0027s an epithelium around each of these follicles."},{"Start":"01:36.960 ","End":"01:40.984","Text":"The follicles within them contain a colloid,"},{"Start":"01:40.984 ","End":"01:42.785","Text":"which is a viscous liquid,"},{"Start":"01:42.785 ","End":"01:50.035","Text":"and it stores within it that\u0027s within the colloid is something called thyroglobulin."},{"Start":"01:50.035 ","End":"01:56.630","Text":"That is going to be a precursor to the hormones that are produced by the thyroid."},{"Start":"01:56.630 ","End":"02:00.950","Text":"Let\u0027s look at them in a little bit more detail in a minute."},{"Start":"02:00.950 ","End":"02:04.700","Text":"The follicles then produce these hormones that can be stored in"},{"Start":"02:04.700 ","End":"02:10.135","Text":"the colloid and then they\u0027re released when needed into the blood."},{"Start":"02:10.135 ","End":"02:14.735","Text":"So 2 of the hormones that are produced by"},{"Start":"02:14.735 ","End":"02:20.765","Text":"the thyroid are called thyroxine and triiodothyronine."},{"Start":"02:20.765 ","End":"02:28.050","Text":"Now notice, its triiodo sometimes is also 4 iodines."},{"Start":"02:28.050 ","End":"02:33.515","Text":"These hormones T_3 and T_4 contain atoms of iodine,"},{"Start":"02:33.515 ","End":"02:36.260","Text":"either 4 atoms or 3 atoms,"},{"Start":"02:36.260 ","End":"02:38.210","Text":"depending on which one we\u0027re talking about."},{"Start":"02:38.210 ","End":"02:44.690","Text":"These hormones have a function in regulating temperature of the body."},{"Start":"02:44.690 ","End":"02:46.690","Text":"Now, how does that happen?"},{"Start":"02:46.690 ","End":"02:49.610","Text":"The hypothalamus, you remember,"},{"Start":"02:49.610 ","End":"02:53.375","Text":"will stimulate with TRH,"},{"Start":"02:53.375 ","End":"02:57.775","Text":"the anterior pituitary, which then releases TSH."},{"Start":"02:57.775 ","End":"03:04.070","Text":"TSH was one of the hormones that\u0027s released by the anterior pituitary."},{"Start":"03:04.070 ","End":"03:10.520","Text":"The TSH then is picked up by receptors in the thyroid glands and"},{"Start":"03:10.520 ","End":"03:17.840","Text":"causes the release of the T_3 and T_4 hormones from the thyroid gland."},{"Start":"03:17.840 ","End":"03:22.580","Text":"What do they do? They regulate the amount"},{"Start":"03:22.580 ","End":"03:28.400","Text":"of mitochondrial ATP that is produced."},{"Start":"03:28.400 ","End":"03:33.650","Text":"Remember, mitochondria are the powerhouses of the cells."},{"Start":"03:33.650 ","End":"03:36.110","Text":"If respiration is increased,"},{"Start":"03:36.110 ","End":"03:37.775","Text":"more ATP is made,"},{"Start":"03:37.775 ","End":"03:40.265","Text":"temperature will go up."},{"Start":"03:40.265 ","End":"03:45.440","Text":"The temperature of the body is regulated at least in parts by"},{"Start":"03:45.440 ","End":"03:51.110","Text":"these T_3 and T_4 hormones maintaining homeostasis."},{"Start":"03:51.110 ","End":"03:53.985","Text":"Now, if the homeostasis is disturbed,"},{"Start":"03:53.985 ","End":"03:56.765","Text":"so for instance, we have low body temperature,"},{"Start":"03:56.765 ","End":"04:06.515","Text":"then the hypothalamus will then go into action producing more or less of TSH,"},{"Start":"04:06.515 ","End":"04:12.485","Text":"which in turn will change the amount of T_4, T_5 hormone."},{"Start":"04:12.485 ","End":"04:18.855","Text":"Now another hormone that\u0027s produced by the thyroid is calcitonin."},{"Start":"04:18.855 ","End":"04:23.660","Text":"It\u0027s produced by particular cells that are called parafollicular cells,"},{"Start":"04:23.660 ","End":"04:27.110","Text":"c cells that are in the thyroid and that is"},{"Start":"04:27.110 ","End":"04:32.430","Text":"involved in calcium levels that are in the blood."},{"Start":"04:32.430 ","End":"04:36.655","Text":"It\u0027s regulated by calcium ion concentration in the blood and"},{"Start":"04:36.655 ","End":"04:41.740","Text":"levels of calcitonin rise when calcium blood levels rise."},{"Start":"04:41.740 ","End":"04:47.945","Text":"Calcitonin up when calcium levels go up and they"},{"Start":"04:47.945 ","End":"04:50.990","Text":"inhibit osteoclast activity in the bones and"},{"Start":"04:50.990 ","End":"04:55.120","Text":"stimulate the excretion of calcium in the kidneys."},{"Start":"04:55.120 ","End":"04:59.840","Text":"The osteoclasts, when their activity increases,"},{"Start":"04:59.840 ","End":"05:02.120","Text":"put calcium into the blood."},{"Start":"05:02.120 ","End":"05:08.375","Text":"This calcitonin inhibits osteoclasts activity."},{"Start":"05:08.375 ","End":"05:15.770","Text":"It also causes excretion of calcium from the bloodstream in the kidneys."},{"Start":"05:15.770 ","End":"05:21.740","Text":"The combination of these things lowers body fluid,"},{"Start":"05:21.740 ","End":"05:24.520","Text":"blood levels of calcium."},{"Start":"05:24.520 ","End":"05:26.570","Text":"Now, in addition to the thyroid,"},{"Start":"05:26.570 ","End":"05:30.420","Text":"let\u0027s look at the parathyroid glands,"},{"Start":"05:30.420 ","End":"05:33.510","Text":"they\u0027re on the back of the thyroid."},{"Start":"05:33.510 ","End":"05:39.140","Text":"Here you can see 4 different glands and there can be between 2 and 6 of them."},{"Start":"05:39.140 ","End":"05:40.910","Text":"They\u0027re located on the back, as we said,"},{"Start":"05:40.910 ","End":"05:47.060","Text":"and each one contains its secretory cells that have a capillary network."},{"Start":"05:47.060 ","End":"05:51.710","Text":"Now, they put these parathyroid glands"},{"Start":"05:51.710 ","End":"05:57.020","Text":"produce parathyroid hormone or PTH. What does it do?"},{"Start":"05:57.020 ","End":"06:00.890","Text":"It\u0027s also involved in blood calcium concentrations,"},{"Start":"06:00.890 ","End":"06:04.235","Text":"but in an opposite way from calcitonin."},{"Start":"06:04.235 ","End":"06:09.775","Text":"It enhances reabsorption of calcium by the kidneys."},{"Start":"06:09.775 ","End":"06:13.550","Text":"Calcium then is taken out of the blood and it"},{"Start":"06:13.550 ","End":"06:19.285","Text":"stimulates osteoclast activity, inhibits osteoblast activity."},{"Start":"06:19.285 ","End":"06:26.300","Text":"In doing this, it stimulates the synthesis and secretion of calcitriol by"},{"Start":"06:26.300 ","End":"06:33.625","Text":"the kidneys and that enhances calcium absorption by the digestive system as well."},{"Start":"06:33.625 ","End":"06:36.875","Text":"They work in opposition to one another,"},{"Start":"06:36.875 ","End":"06:40.460","Text":"the calcitonin and parathyroid hormone,"},{"Start":"06:40.460 ","End":"06:43.500","Text":"as we mentioned before."}],"ID":30229},{"Watched":false,"Name":"The Adrenal Gland","Duration":"5m 49s","ChapterTopicVideoID":28702,"CourseChapterTopicPlaylistID":286915,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:07.230","Text":"Let\u0027s now move on in our discussion of the endocrine glands to the adrenal glands."},{"Start":"00:07.230 ","End":"00:11.190","Text":"Sometimes they\u0027re also known as the suprarenal glands because"},{"Start":"00:11.190 ","End":"00:15.585","Text":"renal means kidney and they are super, they\u0027re above them."},{"Start":"00:15.585 ","End":"00:18.720","Text":"We\u0027re not talking about the adrenal glands and we\u0027ll"},{"Start":"00:18.720 ","End":"00:21.750","Text":"see the adrenal gland is actually quite complicated."},{"Start":"00:21.750 ","End":"00:26.400","Text":"As I said, they\u0027re located on the top of each kidney and"},{"Start":"00:26.400 ","End":"00:31.759","Text":"they consist of a cortex and a medulla."},{"Start":"00:31.759 ","End":"00:39.325","Text":"The medulla will be the central part and the cortex will be more on the outside."},{"Start":"00:39.325 ","End":"00:42.890","Text":"Let\u0027s have a look at these different regions."},{"Start":"00:42.890 ","End":"00:48.035","Text":"The cortex itself can be subdivided into 3 different regions,"},{"Start":"00:48.035 ","End":"00:53.635","Text":"and each of them produces different hormones."},{"Start":"00:53.635 ","End":"00:57.620","Text":"The outer one produces mineralocorticoids,"},{"Start":"00:57.620 ","End":"01:03.455","Text":"and then the central one produces glucocorticoids,"},{"Start":"01:03.455 ","End":"01:11.105","Text":"whereas the inner one produces androgens as well as catecholamines."},{"Start":"01:11.105 ","End":"01:15.205","Text":"Let\u0027s first now look at the mineralocorticoids."},{"Start":"01:15.205 ","End":"01:21.290","Text":"The main one is called aldosterone,"},{"Start":"01:21.290 ","End":"01:23.870","Text":"and it is produced,"},{"Start":"01:23.870 ","End":"01:27.755","Text":"as we said, by the adrenal cortex."},{"Start":"01:27.755 ","End":"01:35.540","Text":"What it does is it causes the sodium and water reabsorption into the nephrons."},{"Start":"01:35.540 ","End":"01:43.400","Text":"In other words, the sodium and the water go from the blood into the nephrons,"},{"Start":"01:43.400 ","End":"01:47.990","Text":"which are the kidney tubules for excretion and they play"},{"Start":"01:47.990 ","End":"01:53.420","Text":"a central role then regulation of blood pressure and sodium and potassium levels."},{"Start":"01:53.420 ","End":"01:57.440","Text":"They also regulate concentration of sodium ions in urine,"},{"Start":"01:57.440 ","End":"02:00.515","Text":"sweat, pancreas, and saliva."},{"Start":"02:00.515 ","End":"02:04.370","Text":"The release of aldosterone is stimulated by"},{"Start":"02:04.370 ","End":"02:08.840","Text":"a decrease in blood concentrations of sodium ions,"},{"Start":"02:08.840 ","End":"02:11.450","Text":"blood volume, or blood pressure,"},{"Start":"02:11.450 ","End":"02:15.030","Text":"as you can see in the left side of this figure."},{"Start":"02:15.030 ","End":"02:19.805","Text":"The next hormone we wanted to talk about where the glucocorticoids."},{"Start":"02:19.805 ","End":"02:23.270","Text":"There are 3 main glucocorticoids,"},{"Start":"02:23.270 ","End":"02:25.630","Text":"which are called cortisol,"},{"Start":"02:25.630 ","End":"02:29.935","Text":"corticosterone, and cortisone."},{"Start":"02:29.935 ","End":"02:33.740","Text":"The glucocorticoids stimulate the synthesis of glucose"},{"Start":"02:33.740 ","End":"02:37.970","Text":"and they stimulate gluconeogenesis making new glucose,"},{"Start":"02:37.970 ","End":"02:40.375","Text":"yes, by liver cells."},{"Start":"02:40.375 ","End":"02:45.470","Text":"They go into the bloodstream and cause the liver to do those things and they also"},{"Start":"02:45.470 ","End":"02:51.365","Text":"promote the release of fatty acids from fatty tissue or adipose tissue."},{"Start":"02:51.365 ","End":"02:54.290","Text":"They increase blood glucose levels to maintain levels"},{"Start":"02:54.290 ","End":"02:57.110","Text":"within a normal range between meals."},{"Start":"02:57.110 ","End":"03:00.110","Text":"The glucocorticoids, as we mentioned in an earlier video,"},{"Start":"03:00.110 ","End":"03:03.170","Text":"are also important for maintaining sugar levels"},{"Start":"03:03.170 ","End":"03:06.770","Text":"in the bloodstream and they\u0027re secreted in response,"},{"Start":"03:06.770 ","End":"03:10.910","Text":"of course, we\u0027re talking here about the adrenal glands,"},{"Start":"03:10.910 ","End":"03:13.685","Text":"in response to ACTH,"},{"Start":"03:13.685 ","End":"03:18.805","Text":"which you\u0027ll remember is secreted from the hypothalamus."},{"Start":"03:18.805 ","End":"03:24.490","Text":"There is a negative feedback mechanism that keeps the ACTH in check."},{"Start":"03:24.490 ","End":"03:28.125","Text":"Let\u0027s now look at glucocorticoids."},{"Start":"03:28.125 ","End":"03:31.130","Text":"Cortisol, which is one of them,"},{"Start":"03:31.130 ","End":"03:38.665","Text":"prepares the body for fight or flight response by again flooding the blood with glucose."},{"Start":"03:38.665 ","End":"03:41.210","Text":"Yes, it causes heightened memory and attention."},{"Start":"03:41.210 ","End":"03:44.665","Text":"It increases blood pressure, of course,"},{"Start":"03:44.665 ","End":"03:48.905","Text":"and it narrows the arteries and that increases the blood pressure as well."},{"Start":"03:48.905 ","End":"03:52.070","Text":"While another hormone, epinephrine,"},{"Start":"03:52.070 ","End":"03:58.654","Text":"increases the heart rate and increases blood supply to the skeleton muscles."},{"Start":"03:58.654 ","End":"04:01.610","Text":"Finally, let\u0027s talk about androgens,"},{"Start":"04:01.610 ","End":"04:05.960","Text":"which are also released by the adrenal gland."},{"Start":"04:05.960 ","End":"04:14.614","Text":"As we said, and they promote masculinity in small amounts in both males and females."},{"Start":"04:14.614 ","End":"04:17.465","Text":"They don\u0027t affect the sexual characteristics,"},{"Start":"04:17.465 ","End":"04:22.135","Text":"but they may supplement the sex hormones that are released from the gonads."},{"Start":"04:22.135 ","End":"04:25.050","Text":"The adrenal medulla, now,"},{"Start":"04:25.050 ","End":"04:29.000","Text":"it\u0027s a different part of the adrenal gland."},{"Start":"04:29.000 ","End":"04:31.520","Text":"It\u0027s more in the center,"},{"Start":"04:31.520 ","End":"04:33.950","Text":"the adrenal medulla cells."},{"Start":"04:33.950 ","End":"04:39.125","Text":"They\u0027re innervated by nerves from the sympathetic nervous system, as you can see,"},{"Start":"04:39.125 ","End":"04:44.900","Text":"that come from the thoracic splanchnic nerves."},{"Start":"04:44.900 ","End":"04:48.825","Text":"Those are in the spinal cord."},{"Start":"04:48.825 ","End":"04:53.300","Text":"They contain 2 types of secretory cells for catecholamines."},{"Start":"04:53.300 ","End":"04:55.220","Text":"Ones that produce epinephrine,"},{"Start":"04:55.220 ","End":"04:56.899","Text":"some has called adrenaline,"},{"Start":"04:56.899 ","End":"05:00.005","Text":"and that is the adrenal medulla hormone."},{"Start":"05:00.005 ","End":"05:03.230","Text":"It\u0027s a primary adrenal medulla hormone"},{"Start":"05:03.230 ","End":"05:07.080","Text":"and it accounts for most of the medulla secretions."},{"Start":"05:07.810 ","End":"05:11.615","Text":"There are also cells that produce norepinephrine,"},{"Start":"05:11.615 ","End":"05:14.915","Text":"or sometimes it\u0027s called noradrenalin, again,"},{"Start":"05:14.915 ","End":"05:17.835","Text":"epinephrine or norepinephrine,"},{"Start":"05:17.835 ","End":"05:22.100","Text":"and they increase heart rate, breathing rate,"},{"Start":"05:22.100 ","End":"05:24.710","Text":"cardiac muscle contractions and blood pressure,"},{"Start":"05:24.710 ","End":"05:27.050","Text":"and blood glucose levels."},{"Start":"05:27.050 ","End":"05:32.330","Text":"All sorts of things that are all involved in the stress response and of course,"},{"Start":"05:32.330 ","End":"05:37.220","Text":"they accelerate the breakdown of glucose in skeletal muscles and the stored fats in"},{"Start":"05:37.220 ","End":"05:40.400","Text":"the adipose tissue so that there is glucose that\u0027s"},{"Start":"05:40.400 ","End":"05:44.185","Text":"available for responding to any kinds of stress."},{"Start":"05:44.185 ","End":"05:49.680","Text":"And that is the fight or flight response."}],"ID":30230},{"Watched":false,"Name":"The Pancreas","Duration":"4m 5s","ChapterTopicVideoID":28699,"CourseChapterTopicPlaylistID":286915,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.899","Text":"In our continuing discussion of the endocrine glands,"},{"Start":"00:04.899 ","End":"00:08.125","Text":"we\u0027ll now have a look at the pancreas."},{"Start":"00:08.125 ","End":"00:13.060","Text":"The pancreas is located between the stomach and"},{"Start":"00:13.060 ","End":"00:18.945","Text":"the proximal that\u0027s the top part really of the small intestine."},{"Start":"00:18.945 ","End":"00:27.520","Text":"Here\u0027s the pancreas and it is adjacent to a piece of the small intestine."},{"Start":"00:27.520 ","End":"00:33.655","Text":"Now, it contains several different types of excitatory cells,"},{"Start":"00:33.655 ","End":"00:36.550","Text":"that is, it\u0027s a heterocrine gland."},{"Start":"00:36.550 ","End":"00:38.380","Text":"It has, as you can see,"},{"Start":"00:38.380 ","End":"00:45.664","Text":"it has both exocrine and endocrine glands."},{"Start":"00:45.664 ","End":"00:52.375","Text":"What does that mean? There are endocrine cells that are called islets of Langerhans."},{"Start":"00:52.375 ","End":"00:56.480","Text":"Here are these cells here and they release"},{"Start":"00:56.480 ","End":"01:01.610","Text":"various kinds of hormones and we\u0027ll see in a minute which hormones those are."},{"Start":"01:01.610 ","End":"01:03.920","Text":"You\u0027ll see there are several different types."},{"Start":"01:03.920 ","End":"01:07.065","Text":"In addition to that, there are exocrine cells,"},{"Start":"01:07.065 ","End":"01:10.065","Text":"as opposed to the endocrine cells."},{"Start":"01:10.065 ","End":"01:19.520","Text":"The endocrine cells are called Acinar cells and they release digestive enzymes."},{"Start":"01:19.520 ","End":"01:21.810","Text":"They make enzymes, here,"},{"Start":"01:21.810 ","End":"01:25.785","Text":"you can see them here, they\u0027re different from the islets of Langerhans."},{"Start":"01:25.785 ","End":"01:28.120","Text":"Almost all of the pancreas,"},{"Start":"01:28.120 ","End":"01:30.805","Text":"99 percent of it is exocrine."},{"Start":"01:30.805 ","End":"01:33.220","Text":"That is, almost all of it is going to make"},{"Start":"01:33.220 ","End":"01:37.825","Text":"digestive enzymes that are going to go into the pancreatic gut."},{"Start":"01:37.825 ","End":"01:40.450","Text":"Whereas the endocrine, the hormone part of it,"},{"Start":"01:40.450 ","End":"01:42.910","Text":"is only about 1 percent."},{"Start":"01:42.910 ","End":"01:50.780","Text":"But let\u0027s look at those endocrine cells that are in the islets of Langerhans."},{"Start":"01:50.780 ","End":"01:55.930","Text":"The islets of Langerhans actually are made of different kinds of cells."},{"Start":"01:55.930 ","End":"01:58.990","Text":"There are a lot of these islets of Langerhans,"},{"Start":"01:58.990 ","End":"02:02.230","Text":"about 1-3 million different clusters in humans."},{"Start":"02:02.230 ","End":"02:04.735","Text":"They contain alpha cells,"},{"Start":"02:04.735 ","End":"02:08.175","Text":"beta cells, and delta cells."},{"Start":"02:08.175 ","End":"02:10.670","Text":"Let\u0027s see what each of these is."},{"Start":"02:10.670 ","End":"02:13.655","Text":"The alpha cells produce glucagon,"},{"Start":"02:13.655 ","End":"02:15.845","Text":"something that we\u0027ve met before."},{"Start":"02:15.845 ","End":"02:19.460","Text":"This hormone which promotes breakdown of glycogen to"},{"Start":"02:19.460 ","End":"02:24.260","Text":"glucose and mobilizes the export of glucose into the blood."},{"Start":"02:24.260 ","End":"02:27.410","Text":"The beta cells produce insulin,"},{"Start":"02:27.410 ","End":"02:30.380","Text":"of course, we\u0027ve met insulin before. What does that do?"},{"Start":"02:30.380 ","End":"02:35.380","Text":"That signals the liver and the muscle cells to take in glucose from the blood."},{"Start":"02:35.380 ","End":"02:39.830","Text":"Notice this is the opposite of the alpha cells and both of"},{"Start":"02:39.830 ","End":"02:44.735","Text":"them are made by the same group of cells."},{"Start":"02:44.735 ","End":"02:46.490","Text":"While not the particular cells,"},{"Start":"02:46.490 ","End":"02:50.450","Text":"they\u0027re different cells, but they\u0027re both in the islets of Langerhans."},{"Start":"02:50.450 ","End":"02:54.035","Text":"Finally, there are delta cells and what do they do?"},{"Start":"02:54.035 ","End":"02:58.850","Text":"They inhibit the secretion of glucagon and insulin."},{"Start":"02:58.850 ","End":"03:02.170","Text":"They kind of lower the whole story."},{"Start":"03:02.170 ","End":"03:04.865","Text":"There seems to be a regulatory mechanism,"},{"Start":"03:04.865 ","End":"03:09.469","Text":"all of which is incorporated into the islets of Langerhans."},{"Start":"03:09.469 ","End":"03:13.175","Text":"This is again a figure that we\u0027ve seen before."},{"Start":"03:13.175 ","End":"03:20.610","Text":"And I\u0027ll remind you then that as blood glucose levels decline,"},{"Start":"03:20.610 ","End":"03:23.000","Text":"so glucose levels decline,"},{"Start":"03:23.000 ","End":"03:27.250","Text":"what happens the islets of Langerhans on the pancreas,"},{"Start":"03:27.250 ","End":"03:28.595","Text":"take note of that."},{"Start":"03:28.595 ","End":"03:35.840","Text":"They produce glucagon and that raises the amount of glucose that\u0027s in the bloodstream."},{"Start":"03:35.840 ","End":"03:41.225","Text":"But when the bloodstream gets to be too high, yes."},{"Start":"03:41.225 ","End":"03:43.230","Text":"Then the opposite happens again,"},{"Start":"03:43.230 ","End":"03:45.380","Text":"in the islets of Langerhans."},{"Start":"03:45.380 ","End":"03:50.270","Text":"What happens? That there is insulin produced now by"},{"Start":"03:50.270 ","End":"03:54.770","Text":"the beta cells that are in the islets of Langerhans and that"},{"Start":"03:54.770 ","End":"03:58.550","Text":"stimulates glucose uptake by the cells and that will"},{"Start":"03:58.550 ","End":"04:05.040","Text":"lower the rate of glucose uptake in the cells."}],"ID":30227},{"Watched":false,"Name":"The Pineal Gland","Duration":"3m 44s","ChapterTopicVideoID":28700,"CourseChapterTopicPlaylistID":286915,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:01.650","Text":"Hi, welcome back."},{"Start":"00:01.650 ","End":"00:04.920","Text":"We\u0027re going to continue now with our discussion of the endocrine glands"},{"Start":"00:04.920 ","End":"00:08.370","Text":"and turn our attention to a small gland,"},{"Start":"00:08.370 ","End":"00:11.050","Text":"which is in the center of the brain here,"},{"Start":"00:11.050 ","End":"00:15.180","Text":"deep in the brain called the pineal gland."},{"Start":"00:15.180 ","End":"00:18.188","Text":"It\u0027s very small, it\u0027s about the size of a pea,"},{"Start":"00:18.188 ","End":"00:21.575","Text":"and sometimes it\u0027s described as the seat of the soul,"},{"Start":"00:21.575 ","End":"00:23.460","Text":"because as you\u0027ll see,"},{"Start":"00:23.460 ","End":"00:28.440","Text":"it has to do with when we\u0027re awake and we\u0027re not awake, and that thing."},{"Start":"00:28.440 ","End":"00:32.505","Text":"It releases melatonin."},{"Start":"00:32.505 ","End":"00:39.470","Text":"Melatonin is a very small molecule as you can see over here."},{"Start":"00:39.470 ","End":"00:42.260","Text":"It\u0027s a hormone and what does it do?"},{"Start":"00:42.260 ","End":"00:46.130","Text":"It helps maintain our circadian cycle that is"},{"Start":"00:46.130 ","End":"00:52.045","Text":"our sleep-wake cycle and it regulates reproductive hormones as well."},{"Start":"00:52.045 ","End":"00:55.985","Text":"It\u0027s sometimes called the sleep hormone and in fact,"},{"Start":"00:55.985 ","End":"00:59.690","Text":"you can even buy this and try to modify"},{"Start":"00:59.690 ","End":"01:07.400","Text":"your sleep wake patterns and it\u0027s particularly useful as a help getting over jet lag."},{"Start":"01:07.400 ","End":"01:12.480","Text":"Now interestingly, there are collaterals."},{"Start":"01:12.480 ","End":"01:17.360","Text":"Collaterals are branches of nerves"},{"Start":"01:17.360 ","End":"01:20.210","Text":"from the visual pathway that innervates really"},{"Start":"01:20.210 ","End":"01:23.110","Text":"in other words it goes into the pineal gland."},{"Start":"01:23.110 ","End":"01:28.730","Text":"There\u0027s some nerves that go into the pineal gland from our eyes and that is"},{"Start":"01:28.730 ","End":"01:35.020","Text":"what\u0027s going to modify how much of this melatonin is released and when."},{"Start":"01:35.020 ","End":"01:39.920","Text":"Actually how it really works completely is not fully understood."},{"Start":"01:39.920 ","End":"01:42.835","Text":"Now let\u0027s look at the action of the melatonin."},{"Start":"01:42.835 ","End":"01:47.030","Text":"The melatonin increases at night when it\u0027s dark,"},{"Start":"01:47.030 ","End":"01:50.870","Text":"and it controls all things."},{"Start":"01:50.870 ","End":"01:52.640","Text":"As you can see down here,"},{"Start":"01:52.640 ","End":"01:58.835","Text":"all different aspects of our life including developmental things and"},{"Start":"01:58.835 ","End":"02:01.310","Text":"immune system and brain protection and"},{"Start":"02:01.310 ","End":"02:06.045","Text":"all things of that sort and in some animals and some mammals,"},{"Start":"02:06.045 ","End":"02:08.180","Text":"it has an inhibitory effect on"},{"Start":"02:08.180 ","End":"02:13.050","Text":"reproductive functions by decreasing production maturation of sperm,"},{"Start":"02:13.050 ","End":"02:15.875","Text":"oocytes, and reproductive organs."},{"Start":"02:15.875 ","End":"02:20.450","Text":"It\u0027s also an effective antioxidant and it protects the central nervous system for"},{"Start":"02:20.450 ","End":"02:25.340","Text":"erotic free-radicals such as nitric oxide and hydrogen peroxide."},{"Start":"02:25.340 ","End":"02:30.170","Text":"It\u0027s mostly, and this is really what\u0027s concerns us most is that it"},{"Start":"02:30.170 ","End":"02:34.640","Text":"involves the biological rhythms as we\u0027ve mentioned before,"},{"Start":"02:34.640 ","End":"02:39.995","Text":"the circadian rhythms, that is day and night rhythms that have to do with sleep,"},{"Start":"02:39.995 ","End":"02:43.580","Text":"wake cycle, as well as eating habits."},{"Start":"02:43.580 ","End":"02:49.055","Text":"Now if we look at this day, full 24-hour period,"},{"Start":"02:49.055 ","End":"02:56.510","Text":"we can see that it does different things at different times, the melatonin."},{"Start":"02:56.510 ","End":"03:00.545","Text":"It\u0027s involved in this circadian rhythm."},{"Start":"03:00.545 ","End":"03:04.130","Text":"These are these 24-hour cycles and it affects"},{"Start":"03:04.130 ","End":"03:07.610","Text":"the sleep patterns because it affects different things that"},{"Start":"03:07.610 ","End":"03:16.085","Text":"happen in our brain as we are sleeping or as we are awake."},{"Start":"03:16.085 ","End":"03:22.126","Text":"This circadian rhythms are therefore adjusted to the local environment,"},{"Start":"03:22.126 ","End":"03:27.020","Text":"that\u0027s the dark and light and well as other things like temperature."},{"Start":"03:27.020 ","End":"03:31.220","Text":"Usually the temperature is a little bit lower at night so these things are sensed,"},{"Start":"03:31.220 ","End":"03:35.540","Text":"and the pineal gland then releases melatonin accordingly,"},{"Start":"03:35.540 ","End":"03:38.210","Text":"as well as redox cycles,"},{"Start":"03:38.210 ","End":"03:44.610","Text":"that is reduction oxidation reactions that occur in different parts of our body."}],"ID":30228},{"Watched":false,"Name":"The Gonads and Summary","Duration":"7m 6s","ChapterTopicVideoID":28703,"CourseChapterTopicPlaylistID":286915,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.490","Text":"This will be our last video discussing endocrine glands in which we\u0027ll discuss the gonads"},{"Start":"00:05.490 ","End":"00:10.910","Text":"briefly and then we\u0027ll summarize what we\u0027ve learned in a tabular form."},{"Start":"00:10.910 ","End":"00:17.040","Text":"The gonads are the male and female organs."},{"Start":"00:17.040 ","End":"00:19.740","Text":"Yes, the testes and the ovaries."},{"Start":"00:19.740 ","End":"00:22.320","Text":"They produce steroid hormones,"},{"Start":"00:22.320 ","End":"00:27.420","Text":"that\u0027s the class of hormones that they produce."},{"Start":"00:27.420 ","End":"00:31.095","Text":"The testes produce androgens,"},{"Start":"00:31.095 ","End":"00:34.325","Text":"that is, testosterone is the most prominent one."},{"Start":"00:34.325 ","End":"00:40.510","Text":"Androgens, you\u0027ll remember, are these hormones that promote growth and development."},{"Start":"00:40.510 ","End":"00:42.560","Text":"The testosterone, what does it do?"},{"Start":"00:42.560 ","End":"00:48.980","Text":"It allows for the development of secondary sex characteristics and things like hair,"},{"Start":"00:48.980 ","End":"00:51.905","Text":"and muscle growth,"},{"Start":"00:51.905 ","End":"00:55.475","Text":"and the production of sperm cells."},{"Start":"00:55.475 ","End":"00:57.410","Text":"The ovaries, on the other hand,"},{"Start":"00:57.410 ","End":"01:00.200","Text":"produce estrogen and progesterone,"},{"Start":"01:00.200 ","End":"01:03.210","Text":"these are the female hormones,"},{"Start":"01:03.210 ","End":"01:07.280","Text":"and of course they are involved in causing"},{"Start":"01:07.280 ","End":"01:12.530","Text":"secondary sex characteristics such as breast development,"},{"Start":"01:12.530 ","End":"01:14.975","Text":"and during the menstrual cycle,"},{"Start":"01:14.975 ","End":"01:18.425","Text":"they prepare the body for childbirth."},{"Start":"01:18.425 ","End":"01:22.145","Text":"Now, let\u0027s look at our summary."},{"Start":"01:22.145 ","End":"01:28.730","Text":"We\u0027re going to have a summary table here and I suggest that you take a picture of"},{"Start":"01:28.730 ","End":"01:33.635","Text":"this table and the following few pages"},{"Start":"01:33.635 ","End":"01:39.440","Text":"so that you can get an overview of what\u0027s the different glands do then,"},{"Start":"01:39.440 ","End":"01:42.680","Text":"say the hypothalamus, the pituitary,"},{"Start":"01:42.680 ","End":"01:44.480","Text":"the thyroid, parathyroid,"},{"Start":"01:44.480 ","End":"01:45.815","Text":"adrenal, and so on."},{"Start":"01:45.815 ","End":"01:50.450","Text":"What the hormones are that are associated with each"},{"Start":"01:50.450 ","End":"01:55.640","Text":"of these glands and then what the effect of them is."},{"Start":"01:55.640 ","End":"01:57.580","Text":"We\u0027ll go through this very quickly,"},{"Start":"01:57.580 ","End":"02:00.680","Text":"the hypothalamus produces releasing"},{"Start":"02:00.680 ","End":"02:05.370","Text":"inhibitory hormones that regulate release from the pituitary glands,"},{"Start":"02:05.370 ","End":"02:07.050","Text":"that\u0027s the next gland we see here,"},{"Start":"02:07.050 ","End":"02:12.860","Text":"produce oxytocin, produce uterine contractions and milk secretion in females,"},{"Start":"02:12.860 ","End":"02:15.935","Text":"the hypothalamus produces the ADH,"},{"Start":"02:15.935 ","End":"02:17.945","Text":"the anti-diuretic hormone,"},{"Start":"02:17.945 ","End":"02:20.810","Text":"that is involved in watery absorption from the kidneys"},{"Start":"02:20.810 ","End":"02:25.145","Text":"and vasoconstriction to increase blood pressure."},{"Start":"02:25.145 ","End":"02:29.975","Text":"Of course, these hormones that are involved in regulation of the pituitary."},{"Start":"02:29.975 ","End":"02:33.500","Text":"The next endocrine gland we want to look at is the pituitary,"},{"Start":"02:33.500 ","End":"02:38.360","Text":"which is divided into the anterior and posterior sections."},{"Start":"02:38.360 ","End":"02:44.210","Text":"The anterior part of it produces growth hormone, prolactin, ACTH,"},{"Start":"02:44.210 ","End":"02:50.620","Text":"FSH, LH, and melanocyte-stimulating hormone, MSH."},{"Start":"02:50.620 ","End":"02:57.770","Text":"Yes, and each of these has a different effect that you can see here on the right."},{"Start":"02:57.770 ","End":"03:00.410","Text":"Growth hormone promotes growth of body tissues,"},{"Start":"03:00.410 ","End":"03:02.270","Text":"protein synthesis, metabolic functions."},{"Start":"03:02.270 ","End":"03:04.939","Text":"Prolactin promotes milk production."},{"Start":"03:04.939 ","End":"03:10.325","Text":"ACTH stimulates the thyroid hormone release,"},{"Start":"03:10.325 ","End":"03:12.055","Text":"and we\u0027ll see that a bit later."},{"Start":"03:12.055 ","End":"03:19.540","Text":"FSH has to do with hormone release by the adrenal cortex and glucocorticoids."},{"Start":"03:19.540 ","End":"03:23.930","Text":"FSH also stimulates gamete production both in ova and sperm,"},{"Start":"03:23.930 ","End":"03:25.130","Text":"secretion of estradiol,"},{"Start":"03:25.130 ","End":"03:28.975","Text":"these are all things that we\u0027ve discussed in the previous videos."},{"Start":"03:28.975 ","End":"03:33.620","Text":"LH, luteinizing hormone stimulates androgen production by the gonads,"},{"Start":"03:33.620 ","End":"03:36.095","Text":"ovulation secretion of progesterone."},{"Start":"03:36.095 ","End":"03:41.485","Text":"This has to do with preparing the female again for childbirth."},{"Start":"03:41.485 ","End":"03:43.910","Text":"The melanocyte-stimulating hormone,"},{"Start":"03:43.910 ","End":"03:50.245","Text":"MSH stimulates melanocytes in the skin to increase pigments production."},{"Start":"03:50.245 ","End":"03:54.260","Text":"Now moving on to the posterior pituitary,"},{"Start":"03:54.260 ","End":"03:55.925","Text":"the associated hormones,"},{"Start":"03:55.925 ","End":"04:00.785","Text":"ADH and oxytocin, actually were produced, if you remember,"},{"Start":"04:00.785 ","End":"04:04.045","Text":"by the hypothalamus,"},{"Start":"04:04.045 ","End":"04:05.750","Text":"but they go straight through"},{"Start":"04:05.750 ","End":"04:09.935","Text":"the posterior pituitary and they stimulate watery absorption as we\u0027ve said,"},{"Start":"04:09.935 ","End":"04:15.020","Text":"and the oxytocin stimulates uterine contractions during childbirth."},{"Start":"04:15.020 ","End":"04:22.660","Text":"Sometimes oxytocin is given as a drug to induce childbirth, milk ejection,"},{"Start":"04:22.660 ","End":"04:26.540","Text":"and stimulates the ductus deferens and"},{"Start":"04:26.540 ","End":"04:30.935","Text":"prostate gland contraction during emission of sperm."},{"Start":"04:30.935 ","End":"04:36.169","Text":"The thyroid then produces different hormones,"},{"Start":"04:36.169 ","End":"04:41.045","Text":"thyroxine and the triiodothyronine."},{"Start":"04:41.045 ","End":"04:46.235","Text":"What did they do? They stimulate to maintain metabolism, growth and development."},{"Start":"04:46.235 ","End":"04:49.430","Text":"The thyroid also produces calcitonin,"},{"Start":"04:49.430 ","End":"04:54.530","Text":"if you remember, that has to do with the reduction of calcium levels in the blood."},{"Start":"04:54.530 ","End":"04:59.660","Text":"On the other hand, attached to the thyroid is the parathyroid."},{"Start":"04:59.660 ","End":"05:04.340","Text":"Remember there are between 4 and 6 of these groups of cells and they produce"},{"Start":"05:04.340 ","End":"05:11.785","Text":"the parathyroid hormone that increases the calcium blood levels."},{"Start":"05:11.785 ","End":"05:18.020","Text":"The adrenal gland has the cortex and the medulla."},{"Start":"05:18.020 ","End":"05:22.565","Text":"The cortex produces aldosterone,"},{"Start":"05:22.565 ","End":"05:27.605","Text":"which increases blood sodium levels as well as potassium secretion."},{"Start":"05:27.605 ","End":"05:31.250","Text":"It also produces cortisol, corticosterone,"},{"Start":"05:31.250 ","End":"05:34.925","Text":"and cortisone and those increased blood glucose levels"},{"Start":"05:34.925 ","End":"05:40.320","Text":"and of course they have anti-inflammatory effects as well."},{"Start":"05:41.480 ","End":"05:46.765","Text":"The adrenal medulla produces epinephrine and neopinephrin"},{"Start":"05:46.765 ","End":"05:52.100","Text":"which stimulate the fight or flight response and increased blood glucose levels,"},{"Start":"05:52.100 ","End":"05:53.660","Text":"increased metabolic activities,"},{"Start":"05:53.660 ","End":"05:57.740","Text":"so that we can get ready to either run or fight."},{"Start":"05:57.740 ","End":"06:00.470","Text":"We\u0027ll move on now to the pancreas."},{"Start":"06:00.470 ","End":"06:04.340","Text":"The pancreas produces 2 different hormones,"},{"Start":"06:04.340 ","End":"06:06.260","Text":"insulin and glucagon, of course,"},{"Start":"06:06.260 ","End":"06:08.555","Text":"which work in opposing directions."},{"Start":"06:08.555 ","End":"06:11.630","Text":"Insulin reduces blood glucose levels and"},{"Start":"06:11.630 ","End":"06:15.140","Text":"glucagon increases blood glucose levels and there is"},{"Start":"06:15.140 ","End":"06:17.660","Text":"a feedback regulation mechanism that"},{"Start":"06:17.660 ","End":"06:22.190","Text":"controls how much insulin and how much glucagon is produced."},{"Start":"06:22.190 ","End":"06:26.390","Text":"Next is the pineal gland, which produces melatonin."},{"Start":"06:26.390 ","End":"06:29.450","Text":"You\u0027ll remember that has to do with biological rhythms,"},{"Start":"06:29.450 ","End":"06:35.375","Text":"circadian clock, and protects the CNS from free radicals, among other things."},{"Start":"06:35.375 ","End":"06:38.630","Text":"Finally, we have the testes and the ovaries in"},{"Start":"06:38.630 ","End":"06:43.325","Text":"males and in females that produce the androgens."},{"Start":"06:43.325 ","End":"06:47.180","Text":"In the males that regulate and promote an increase or"},{"Start":"06:47.180 ","End":"06:51.245","Text":"maintain sperm production and secondary sexual characteristics."},{"Start":"06:51.245 ","End":"06:54.410","Text":"In females estrogen and progestins,"},{"Start":"06:54.410 ","End":"06:58.340","Text":"which promote uterine lining growth female secondary sexual characteristics,"},{"Start":"06:58.340 ","End":"07:01.580","Text":"and of course, the progestins promote and maintain"},{"Start":"07:01.580 ","End":"07:06.780","Text":"uterine lining growth during the menstrual cycle."}],"ID":30231}],"Thumbnail":null,"ID":286915},{"Name":"Organs with Secondary Endocrine Functions","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Organs with Secondary Endocrine Functions","Duration":"8m ","ChapterTopicVideoID":28681,"CourseChapterTopicPlaylistID":286917,"HasSubtitles":true,"ThumbnailPath":"https://www.proprep.uk/Images/Videos_Thumbnails/28681.jpeg","UploadDate":"2022-03-17T07:55:45.0000000","DurationForVideoObject":"PT8M","Description":null,"MetaTitle":"Organs with Secondary Endocrine Functions: Video + Workbook | Proprep","MetaDescription":"Endocrine system - Organs with Secondary Endocrine Functions. Watch the video made by an expert in the field. Download the workbook and maximize your learning.","Canonical":"https://www.proprep.uk/general-modules/all/introduction-to-biology/endocrine-system/organs-with-secondary-endocrine-functions/vid30240","VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.230","Text":"I\u0027m glad that you\u0027re back now and we\u0027re going to finish"},{"Start":"00:04.230 ","End":"00:09.915","Text":"our discussion of endocrine glands and endocrine functions."},{"Start":"00:09.915 ","End":"00:20.050","Text":"With the discussion of organs that have secondary endocrine functions,"},{"Start":"00:21.010 ","End":"00:26.250","Text":"these organs don\u0027t primarily have an endocrine function,"},{"Start":"00:26.250 ","End":"00:29.220","Text":"but they do have an endocrine function."},{"Start":"00:29.220 ","End":"00:32.790","Text":"There are several organs was primary functions are"},{"Start":"00:32.790 ","End":"00:37.369","Text":"non endocrine but also possess endocrine functions."},{"Start":"00:37.369 ","End":"00:46.639","Text":"Now, you\u0027ve seen in our previous videos this list of primary endocrine organs,"},{"Start":"00:46.639 ","End":"00:50.585","Text":"pineal gland, hypothalamus, pituitary gland, and so on."},{"Start":"00:50.585 ","End":"00:52.670","Text":"But there are secondary organs,"},{"Start":"00:52.670 ","End":"00:54.470","Text":"for instance, heart, liver,"},{"Start":"00:54.470 ","End":"00:56.270","Text":"stomach, kidney, small intestine,"},{"Start":"00:56.270 ","End":"01:01.825","Text":"and even the skin that also possess endocrine functions."},{"Start":"01:01.825 ","End":"01:05.570","Text":"Now let\u0027s have a look and see what some of those do."},{"Start":"01:05.570 ","End":"01:08.560","Text":"Let\u0027s start with the heart."},{"Start":"01:08.560 ","End":"01:16.520","Text":"The heart obviously pumps blood and there is an issue of blood pressure."},{"Start":"01:16.520 ","End":"01:22.240","Text":"What the volume of the blood is and how much the pressure is on the heart,"},{"Start":"01:22.240 ","End":"01:25.300","Text":"and that is sensed very well in the heart."},{"Start":"01:25.300 ","End":"01:31.190","Text":"The heart possesses endocrine cells in the walls of the atria that are"},{"Start":"01:31.190 ","End":"01:34.835","Text":"specialized cardiac muscle cells and they produce"},{"Start":"01:34.835 ","End":"01:40.114","Text":"a hormone called atrial natriuretic peptide,"},{"Start":"01:40.114 ","End":"01:42.225","Text":"that\u0027s ANP for shorts,"},{"Start":"01:42.225 ","End":"01:51.245","Text":"and that is produced in response to increased blood levels or blood volume."},{"Start":"01:51.245 ","End":"01:54.350","Text":"Now if their blood volume is too high, of course,"},{"Start":"01:54.350 ","End":"02:02.495","Text":"that stretches the cells and that is what stimulates this hormone to be released."},{"Start":"02:02.495 ","End":"02:06.650","Text":"Now let\u0027s look at this peptide at this hormone."},{"Start":"02:06.650 ","End":"02:11.040","Text":"It acts on the kidneys. Here are the kidneys."},{"Start":"02:11.040 ","End":"02:13.970","Text":"Here\u0027s the heart and the ANP that\u0027s produced."},{"Start":"02:13.970 ","End":"02:18.565","Text":"It acts on the kidneys to reduce the reabsorption of sodium."},{"Start":"02:18.565 ","End":"02:22.355","Text":"So the reabsorption of sodium is reduced."},{"Start":"02:22.355 ","End":"02:31.840","Text":"Then therefore, sodium and water are excreted through the urine more efficiently."},{"Start":"02:31.840 ","End":"02:36.125","Text":"More of the sodium and water are going out of the bloodstream,"},{"Start":"02:36.125 ","End":"02:38.995","Text":"that means less blood volume."},{"Start":"02:38.995 ","End":"02:46.290","Text":"This also results in the reduction of the amount of renin that\u0027s released by the kidneys."},{"Start":"02:46.290 ","End":"02:51.350","Text":"Remember the renin is released by the kidneys and aldosterone is released by"},{"Start":"02:51.350 ","End":"02:59.555","Text":"the adrenal cortex and that further prevents the retention of water."},{"Start":"02:59.555 ","End":"03:01.265","Text":"In this way,"},{"Start":"03:01.265 ","End":"03:05.720","Text":"ANP reduces the blood volume and blood pressure, therefore."},{"Start":"03:05.720 ","End":"03:08.765","Text":"As part of that,"},{"Start":"03:08.765 ","End":"03:12.619","Text":"the concentration of sodium in the blood is released."},{"Start":"03:12.619 ","End":"03:16.745","Text":"Now let\u0027s look at the GI tract, the gastrointestinal tract."},{"Start":"03:16.745 ","End":"03:20.600","Text":"There are various hormones that are produced."},{"Start":"03:20.600 ","End":"03:21.725","Text":"Some of them we discussed,"},{"Start":"03:21.725 ","End":"03:23.345","Text":"others we haven\u0027t discussed,"},{"Start":"03:23.345 ","End":"03:26.315","Text":"discussed for instance, gastrin."},{"Start":"03:26.315 ","End":"03:30.080","Text":"Those hormones aid in digestion by"},{"Start":"03:30.080 ","End":"03:33.980","Text":"acting on other organs such as the pancreas, gallbladder,"},{"Start":"03:33.980 ","End":"03:43.690","Text":"and liver to deliver gastric juices that will help in breakdown and digestion of food."},{"Start":"03:43.690 ","End":"03:50.960","Text":"The GI tract itself can produce some hormones that are then"},{"Start":"03:50.960 ","End":"03:59.225","Text":"acting on organs on the glands which will produce the gastric juices."},{"Start":"03:59.225 ","End":"04:01.920","Text":"Now let\u0027s look at the kidneys."},{"Start":"04:01.920 ","End":"04:05.330","Text":"The kidneys are able to release several hormones."},{"Start":"04:05.330 ","End":"04:10.310","Text":"This is the inside of the kidney in a particular place where we have"},{"Start":"04:10.310 ","End":"04:17.105","Text":"the crossover between the tubules and the arterioles."},{"Start":"04:17.105 ","End":"04:27.170","Text":"We have the exchange of liquids of water and of sodium and calcium and so on,"},{"Start":"04:27.170 ","End":"04:29.405","Text":"through these blood vessels."},{"Start":"04:29.405 ","End":"04:32.675","Text":"The kidneys release several hormones."},{"Start":"04:32.675 ","End":"04:37.850","Text":"Renin, for instances, is released to decrease blood volume or"},{"Start":"04:37.850 ","End":"04:40.880","Text":"pressure and this leads to aldosterone that"},{"Start":"04:40.880 ","End":"04:44.000","Text":"causes retention now of water and raising blood volume."},{"Start":"04:44.000 ","End":"04:50.345","Text":"This is in opposition to the hormones that we saw that are released by the heart."},{"Start":"04:50.345 ","End":"04:58.820","Text":"It\u0027s a feedback mechanism and calcitriol is also emitted or excreted by the kidneys,"},{"Start":"04:58.820 ","End":"05:02.705","Text":"and that aids in the absorption of calcium and phosphate ions."},{"Start":"05:02.705 ","End":"05:06.960","Text":"In addition, the kidneys also released another protein,"},{"Start":"05:06.960 ","End":"05:11.030","Text":"a peptide called erythropoietin or EPO, sometimes for short,"},{"Start":"05:11.030 ","End":"05:16.565","Text":"and it\u0027s released in response to low oxygen levels and that triggers the formation."},{"Start":"05:16.565 ","End":"05:18.650","Text":"It\u0027s a differentiation process,"},{"Start":"05:18.650 ","End":"05:22.850","Text":"the formation of red blood cells in the bone marrow."},{"Start":"05:22.850 ","End":"05:25.895","Text":"The kidneys then are sensing"},{"Start":"05:25.895 ","End":"05:33.170","Text":"the amount of oxygen there is in the blood as well as how much water there"},{"Start":"05:33.170 ","End":"05:38.525","Text":"and sodium there is in a blood and produces hormones in"},{"Start":"05:38.525 ","End":"05:44.735","Text":"small amounts to adjust those levels."},{"Start":"05:44.735 ","End":"05:47.615","Text":"Finally, we\u0027ll look at the thymus,"},{"Start":"05:47.615 ","End":"05:50.360","Text":"not the thyroid, the thymus."},{"Start":"05:50.360 ","End":"05:52.940","Text":"The thymus, you\u0027ll notice,"},{"Start":"05:52.940 ","End":"05:55.850","Text":"is under the sternum."},{"Start":"05:55.850 ","End":"05:59.660","Text":"That is, it\u0027s under the bone that\u0027s in the center of the chest,"},{"Start":"05:59.660 ","End":"06:03.050","Text":"above the lungs, and it\u0027s most prominent than infants."},{"Start":"06:03.050 ","End":"06:05.720","Text":"It becomes smaller during adulthood."},{"Start":"06:05.720 ","End":"06:12.805","Text":"It\u0027s primary function has to do with producing cells for the immune system,"},{"Start":"06:12.805 ","End":"06:16.445","Text":"but it also produces several hormones that are called thymosins."},{"Start":"06:16.445 ","End":"06:20.570","Text":"These are small peptide hormones that do stimulate"},{"Start":"06:20.570 ","End":"06:25.145","Text":"the production of the T cells from the immune system."},{"Start":"06:25.145 ","End":"06:29.735","Text":"But they also stimulate the pituitary gland to release other hormones,"},{"Start":"06:29.735 ","End":"06:32.390","Text":"for instance, growth hormone."},{"Start":"06:32.390 ","End":"06:36.515","Text":"Lastly, we\u0027ll discuss adipose connective tissue."},{"Start":"06:36.515 ","End":"06:41.735","Text":"Another tissue which produces a peptide called leptin,"},{"Start":"06:41.735 ","End":"06:45.920","Text":"which is produced in response to food intake."},{"Start":"06:45.920 ","End":"06:51.405","Text":"Leptin, which is produced by this adipose tissue. Now what does it do?"},{"Start":"06:51.405 ","End":"06:55.220","Text":"Increase the activity of anorexigenic,"},{"Start":"06:55.220 ","End":"06:58.295","Text":"that\u0027s loss of appetite neurons last."},{"Start":"06:58.295 ","End":"07:07.880","Text":"The activity of these neurons is increased and it also decreases neuron activity of those"},{"Start":"07:07.880 ","End":"07:17.630","Text":"that increase appetite orexigenic neurons and that results in the feeling of satiety."},{"Start":"07:17.630 ","End":"07:20.225","Text":"In other words, you don\u0027t want to eat anymore,"},{"Start":"07:20.225 ","End":"07:21.800","Text":"so you feel full."},{"Start":"07:21.800 ","End":"07:25.915","Text":"That\u0027s the function of leptin."},{"Start":"07:25.915 ","End":"07:31.220","Text":"Interestingly, the leptin that is associated with"},{"Start":"07:31.220 ","End":"07:37.985","Text":"reproduction and it must be present for GnRH and gonadotropin synthesis to occur."},{"Start":"07:37.985 ","End":"07:43.205","Text":"Now in extremely thin females that may be anorexic, for instance,"},{"Start":"07:43.205 ","End":"07:51.185","Text":"we can have puberty that arrives late because there\u0027s less leptin and"},{"Start":"07:51.185 ","End":"08:00.240","Text":"therefore the hormones that promotes puberty are produced in lower amounts."}],"ID":30240}],"Thumbnail":null,"ID":286917},{"Name":"Exercise","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Exercise 1","Duration":"46s","ChapterTopicVideoID":28684,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.675","Text":"A newly discovered hormone contains 4 amino acids linked together."},{"Start":"00:06.675 ","End":"00:10.755","Text":"Under which chemical class would this hormone be classified?"},{"Start":"00:10.755 ","End":"00:13.380","Text":"Would it be a lipid-derived hormone?"},{"Start":"00:13.380 ","End":"00:16.000","Text":"Well, this is amino acids."},{"Start":"00:18.380 ","End":"00:21.150","Text":"Amino acid-derived?"},{"Start":"00:21.150 ","End":"00:23.760","Text":"Not really. A peptide hormone?"},{"Start":"00:23.760 ","End":"00:25.305","Text":"Well what\u0027s a peptide hormone?"},{"Start":"00:25.305 ","End":"00:31.995","Text":"You remember that peptide hormones are sensed by a receptor and"},{"Start":"00:31.995 ","End":"00:35.460","Text":"then there is a process of"},{"Start":"00:35.460 ","End":"00:39.510","Text":"signal transduction that happens afterwards to get the signal into the nucleus."},{"Start":"00:39.510 ","End":"00:44.950","Text":"In any case, amino acids linked together are definitely a peptide."}],"ID":30208},{"Watched":false,"Name":"Exercise 2","Duration":"56s","ChapterTopicVideoID":28685,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:08.295","Text":"Which class of hormones can diffuse through the plasma membrane?"},{"Start":"00:08.295 ","End":"00:12.150","Text":"Would it be lipids that can diffuse through the plasma membrane?"},{"Start":"00:12.150 ","End":"00:17.715","Text":"Now let\u0027s remember the plasma membrane is a lipid bilayer,"},{"Start":"00:17.715 ","End":"00:19.950","Text":"so that looks pretty inviting."},{"Start":"00:19.950 ","End":"00:22.160","Text":"What about amino acid-derived hormones?"},{"Start":"00:22.160 ","End":"00:26.179","Text":"We just saw that amino acids have to go through a receptor."},{"Start":"00:26.179 ","End":"00:30.095","Text":"Peptide hormones have to go through a receptor."},{"Start":"00:30.095 ","End":"00:36.375","Text":"Glycoprotein hormones, glycoproteins have sugars on them,"},{"Start":"00:36.375 ","End":"00:40.925","Text":"so they\u0027re going to have difficulty getting through the plasma membrane as well."},{"Start":"00:40.925 ","End":"00:45.340","Text":"So the answer is going to be lipid-derived hormones."},{"Start":"00:45.340 ","End":"00:49.010","Text":"As you can see, steroid hormones are examples of"},{"Start":"00:49.010 ","End":"00:53.015","Text":"those and they go straight through the plasma membrane,"},{"Start":"00:53.015 ","End":"00:56.130","Text":"their receptor is inside the cell."}],"ID":30209},{"Watched":false,"Name":"Exercise 3","Duration":"1m 23s","ChapterTopicVideoID":28686,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.990","Text":"Why are steroids able to diffuse across the plasma membrane?"},{"Start":"00:04.990 ","End":"00:06.715","Text":"Steroids, now,"},{"Start":"00:06.715 ","End":"00:09.630","Text":"why are they able to diffuse across the plasma membrane?"},{"Start":"00:09.630 ","End":"00:11.940","Text":"This is similar to the previous exercise."},{"Start":"00:11.940 ","End":"00:14.850","Text":"Their transport protein moves them through the membrane."},{"Start":"00:14.850 ","End":"00:19.660","Text":"They are amphipathic, allowing them to interact with the entire phospholipid."},{"Start":"00:19.660 ","End":"00:22.480","Text":"They are amphipathic,"},{"Start":"00:22.480 ","End":"00:23.940","Text":"think about what that means,"},{"Start":"00:23.940 ","End":"00:26.700","Text":"allowing them to interact with the entire phospholipid."},{"Start":"00:26.700 ","End":"00:30.780","Text":"Cells express channels that let hormones flow"},{"Start":"00:30.780 ","End":"00:34.710","Text":"down their concentration gradients into cells channels."},{"Start":"00:34.710 ","End":"00:36.825","Text":"They\u0027re non-polar molecules."},{"Start":"00:36.825 ","End":"00:38.925","Text":"Let\u0027s take these 1 at a time."},{"Start":"00:38.925 ","End":"00:43.850","Text":"Certainly, they don\u0027t move through the membrane with a transport membrane."},{"Start":"00:43.850 ","End":"00:45.350","Text":"Let\u0027s see."},{"Start":"00:45.350 ","End":"00:48.320","Text":"Are they amphipathic?"},{"Start":"00:48.320 ","End":"00:54.010","Text":"Amphipathic means that some of the molecule is charged and some isn\u0027t."},{"Start":"00:54.010 ","End":"00:57.965","Text":"Well, actually, steroids are not charged at all,"},{"Start":"00:57.965 ","End":"00:59.270","Text":"or practically not,"},{"Start":"00:59.270 ","End":"01:04.630","Text":"so that\u0027s not what\u0027s allowing them to act with the entire phospholipid."},{"Start":"01:04.630 ","End":"01:08.622","Text":"Cells express channels that allow hormones to float,"},{"Start":"01:08.622 ","End":"01:11.255","Text":"well, that we\u0027ve mentioned before, that\u0027s not the case."},{"Start":"01:11.255 ","End":"01:14.165","Text":"So they\u0027ve got to be non-polar molecules."},{"Start":"01:14.165 ","End":"01:16.745","Text":"They\u0027re non-polar, so that\u0027s the answer."},{"Start":"01:16.745 ","End":"01:19.204","Text":"These are steroids,"},{"Start":"01:19.204 ","End":"01:23.100","Text":"and as you can see, they are non-polar."}],"ID":30210},{"Watched":false,"Name":"Exercise 4","Duration":"1m 7s","ChapterTopicVideoID":28687,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.200","Text":"A new antagonist molecule has been discovered that"},{"Start":"00:04.200 ","End":"00:09.310","Text":"binds to and blocks plasma membrane receptors. Plasma membrane receptors."},{"Start":"00:11.330 ","End":"00:15.390","Text":"What effect will this agonist have on testosterone,"},{"Start":"00:15.390 ","End":"00:17.250","Text":"which is a steroid hormone?"},{"Start":"00:17.250 ","End":"00:19.815","Text":"Now steroids, we said,"},{"Start":"00:19.815 ","End":"00:24.044","Text":"don\u0027t require the plasma membrane receptor."},{"Start":"00:24.044 ","End":"00:27.555","Text":"They go straight through the membrane."},{"Start":"00:27.555 ","End":"00:29.430","Text":"What effect will that have?"},{"Start":"00:29.430 ","End":"00:30.960","Text":"Well, let\u0027s see."},{"Start":"00:30.960 ","End":"00:34.095","Text":"Will it block testosterone from binding its receptor?"},{"Start":"00:34.095 ","End":"00:41.745","Text":"No, because the receptor is going to be inside the cell and not on the plasma membrane."},{"Start":"00:41.745 ","End":"00:45.650","Text":"Will it block testosterone from activating cyclic AMP signaling?"},{"Start":"00:45.650 ","End":"00:46.985","Text":"Has nothing to do with that."},{"Start":"00:46.985 ","End":"00:50.915","Text":"Will it increase testosterone-mediated signaling? Of course not."},{"Start":"00:50.915 ","End":"00:58.505","Text":"It definitely will not affect testosterone-mediated signaling because it\u0027s inside"},{"Start":"00:58.505 ","End":"01:01.670","Text":"the receptors inside the cell and there isn\u0027t any"},{"Start":"01:01.670 ","End":"01:06.990","Text":"testosterone-mediated signaling at the plasma membrane."}],"ID":30211},{"Watched":false,"Name":"Exercise 5","Duration":"55s","ChapterTopicVideoID":28688,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.400","Text":"What effect will a cyclic AMP inhibitor"},{"Start":"00:05.400 ","End":"00:10.365","Text":"have on a peptide hormone mediated signaling pathway?"},{"Start":"00:10.365 ","End":"00:14.039","Text":"Will it prevent the hormone from binding its receptor?"},{"Start":"00:14.039 ","End":"00:17.010","Text":"Cyclic AMP inhibitor."},{"Start":"00:17.010 ","End":"00:19.515","Text":"Will it prevent activation of a G-protein?"},{"Start":"00:19.515 ","End":"00:23.085","Text":"Will it prevent activation of adenylate cyclase,"},{"Start":"00:23.085 ","End":"00:27.255","Text":"or will it prevent activation of protein kinases?"},{"Start":"00:27.255 ","End":"00:31.200","Text":"Well, it\u0027s not going to be any of these first three,"},{"Start":"00:31.200 ","End":"00:33.030","Text":"because if you remember,"},{"Start":"00:33.030 ","End":"00:34.890","Text":"what does cyclic AMP do?"},{"Start":"00:34.890 ","End":"00:42.740","Text":"Cyclic AMP is a second messenger that activates protein kinase A."},{"Start":"00:42.740 ","End":"00:46.175","Text":"So if there\u0027s a cyclic AMP inhibitor,"},{"Start":"00:46.175 ","End":"00:52.505","Text":"then it will inhibit the activation of protein kinase A."},{"Start":"00:52.505 ","End":"00:55.260","Text":"So D is our answer."}],"ID":30212},{"Watched":false,"Name":"Exercise 6","Duration":"1m 16s","ChapterTopicVideoID":28689,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.030","Text":"When insulin binds to its receptor,"},{"Start":"00:03.030 ","End":"00:06.780","Text":"the complex is endocytosed into the cell."},{"Start":"00:06.780 ","End":"00:08.556","Text":"It\u0027s endocytosed."},{"Start":"00:08.556 ","End":"00:14.835","Text":"That means that the core complex moves into the cell."},{"Start":"00:14.835 ","End":"00:19.245","Text":"This is an example of what in response to hormone signaling?"},{"Start":"00:19.245 ","End":"00:23.400","Text":"Cyclic AMP activation, generating an intracellular receptor,"},{"Start":"00:23.400 ","End":"00:29.640","Text":"activation of a hormone response element, or receptor down-regulation?"},{"Start":"00:29.640 ","End":"00:31.860","Text":"Well, if you remember,"},{"Start":"00:31.860 ","End":"00:37.820","Text":"we discussed up and down-regulation of how"},{"Start":"00:37.820 ","End":"00:40.940","Text":"cells with receptors react to their environments by"},{"Start":"00:40.940 ","End":"00:44.300","Text":"the changing of the number of receptors."},{"Start":"00:44.300 ","End":"00:47.870","Text":"We saw an example of up-regulation in which"},{"Start":"00:47.870 ","End":"00:52.915","Text":"the hormone receptor number was increased and that gave us up-regulation."},{"Start":"00:52.915 ","End":"00:55.940","Text":"The opposite of that is down-regulation,"},{"Start":"00:55.940 ","End":"01:00.500","Text":"the number of receptors decreases in response to rising hormone levels,"},{"Start":"01:00.500 ","End":"01:03.865","Text":"and therefore cellular activity is reduced."},{"Start":"01:03.865 ","End":"01:09.530","Text":"When the insulin receptor is endocytosed into the cells,"},{"Start":"01:09.530 ","End":"01:16.140","Text":"they become fewer of them and that\u0027s why we\u0027ve got down-regulation."}],"ID":30213},{"Watched":false,"Name":"Exercise 7","Duration":"1m 21s","ChapterTopicVideoID":28690,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.120","Text":"Drinking alcoholic beverages causes an increase in urine output."},{"Start":"00:06.120 ","End":"00:10.695","Text":"When you drink alcoholic beverages you pee more."},{"Start":"00:10.695 ","End":"00:13.830","Text":"There\u0027s an increase in urine output. Why is that?"},{"Start":"00:13.830 ","End":"00:18.720","Text":"Well, this most likely occurs because alcohol does which of the following things?"},{"Start":"00:18.720 ","End":"00:20.790","Text":"Does it inhibit ADH release?"},{"Start":"00:20.790 ","End":"00:27.900","Text":"Stimulates ADH release, inhibits TSH release or stimulates TSH release."},{"Start":"00:27.900 ","End":"00:32.445","Text":"Remember, TSH is thyroid stimulating hormone."},{"Start":"00:32.445 ","End":"00:35.010","Text":"What does that have to do with alcohol?"},{"Start":"00:35.010 ","End":"00:39.540","Text":"So let\u0027s recall what ADH does."},{"Start":"00:39.540 ","End":"00:43.730","Text":"Well, the ADH effect increases the number"},{"Start":"00:43.730 ","End":"00:48.170","Text":"of aquaporins as the water channels in the kidney tubules."},{"Start":"00:48.170 ","End":"00:54.970","Text":"Remember this is water which is going from the tubule, gets out."},{"Start":"00:54.970 ","End":"01:00.200","Text":"Actually ADH release can be reduced by alcohol"},{"Start":"01:00.200 ","End":"01:05.770","Text":"which causes an increase in urine production and dehydration."},{"Start":"01:05.770 ","End":"01:16.230","Text":"That\u0027s why you will pee more because the ADH release is reduced by alcohol,"},{"Start":"01:16.230 ","End":"01:21.390","Text":"and so there is not as much reabsorption of water."}],"ID":30214},{"Watched":false,"Name":"Exercise 8","Duration":"51s","ChapterTopicVideoID":28691,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.140 ","End":"00:02.865","Text":"Here\u0027s something we just need to remember."},{"Start":"00:02.865 ","End":"00:06.915","Text":"FSH and LH release"},{"Start":"00:06.915 ","End":"00:12.885","Text":"from the anterior pituitary is stimulated by which of the following: TSH,"},{"Start":"00:12.885 ","End":"00:17.055","Text":"GnRH, T_3 or PTH?"},{"Start":"00:17.055 ","End":"00:18.480","Text":"TSH, remember,"},{"Start":"00:18.480 ","End":"00:24.930","Text":"is thyroid-stimulating hormone, PTH is parathyroid hormone,"},{"Start":"00:24.930 ","End":"00:29.712","Text":"T_3 is produced by the thyroid,"},{"Start":"00:29.712 ","End":"00:35.160","Text":"so our answer is going to be GnRH."},{"Start":"00:35.160 ","End":"00:37.250","Text":"If you remember this figure,"},{"Start":"00:37.250 ","End":"00:41.150","Text":"the GnRH is produced by the hypothalamus,"},{"Start":"00:41.150 ","End":"00:48.330","Text":"which stimulates the anterior pituitary to release LH and FSH."},{"Start":"00:48.330 ","End":"00:51.370","Text":"That\u0027s what we were asked."}],"ID":30215},{"Watched":false,"Name":"Exercise 9","Duration":"27s","ChapterTopicVideoID":28692,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.200","Text":"Another question that we just have to remember the answer to."},{"Start":"00:04.200 ","End":"00:08.040","Text":"What hormone is produced by the Beta cells of the pancreas?"},{"Start":"00:08.040 ","End":"00:14.430","Text":"Just remember, the Beta cells are part of the islets of Langerhans in the pancreas,"},{"Start":"00:14.430 ","End":"00:19.350","Text":"and we\u0027ll just remember that our answer is going to be insulin."},{"Start":"00:19.350 ","End":"00:21.135","Text":"Remember this figure here,"},{"Start":"00:21.135 ","End":"00:27.460","Text":"the Beta cells of the pancreas are producing insulin."}],"ID":30216},{"Watched":false,"Name":"Exercise 10","Duration":"1m 18s","ChapterTopicVideoID":28693,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.170","Text":"When blood calcium levels are low,"},{"Start":"00:04.170 ","End":"00:07.485","Text":"what does PTH stimulate?"},{"Start":"00:07.485 ","End":"00:10.050","Text":"The parathyroid, if you remember,"},{"Start":"00:10.050 ","End":"00:11.280","Text":"what does it stimulate?"},{"Start":"00:11.280 ","End":"00:14.700","Text":"This is the excretion of calcium from the kidneys."},{"Start":"00:14.700 ","End":"00:18.030","Text":"The excretion of calcium from the intestines."},{"Start":"00:18.030 ","End":"00:23.235","Text":"Does it stimulate osteoblasts or osteoclasts?"},{"Start":"00:23.235 ","End":"00:27.000","Text":"Osteoblasts, you\u0027ll remember are pre bone cells,"},{"Start":"00:27.000 ","End":"00:31.289","Text":"osteoclasts are bone cells."},{"Start":"00:31.289 ","End":"00:34.605","Text":"Calcium levels are low,"},{"Start":"00:34.605 ","End":"00:36.240","Text":"we\u0027re going to need in the blood."},{"Start":"00:36.240 ","End":"00:37.610","Text":"We\u0027re going to need more calcium,"},{"Start":"00:37.610 ","End":"00:38.690","Text":"where can it come from?"},{"Start":"00:38.690 ","End":"00:45.490","Text":"It really could either come from the intestines or it could come from these osteoclasts."},{"Start":"00:45.490 ","End":"00:49.880","Text":"It\u0027s actually not going to be excretion of calcium from the intestines,"},{"Start":"00:49.880 ","End":"00:53.015","Text":"that will be the wrong direction, we would want absorption of calcium."},{"Start":"00:53.015 ","End":"00:56.570","Text":"The answer is going to be osteoclasts."},{"Start":"00:56.570 ","End":"01:01.250","Text":"Remember this figure? The PTH regulates blood calcium concentrations by"},{"Start":"01:01.250 ","End":"01:06.470","Text":"enhancing reabsorption of calcium by the kidneys."},{"Start":"01:06.470 ","End":"01:10.370","Text":"Yes. But also by"},{"Start":"01:10.370 ","End":"01:17.790","Text":"stimulating osteoclast activity and inhibiting osteoblast activity."}],"ID":30217},{"Watched":false,"Name":"Exercise 11","Duration":"1m 31s","ChapterTopicVideoID":28694,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.793","Text":"How would mutations that completely ablate, that\u0027s a race."},{"Start":"00:04.793 ","End":"00:14.850","Text":"The function of the androgen receptors"},{"Start":"00:14.850 ","End":"00:20.310","Text":"impact the phenotypic development of humans with XY chromosomes?"},{"Start":"00:20.310 ","End":"00:22.890","Text":"XY are going to be males,"},{"Start":"00:22.890 ","End":"00:30.165","Text":"but these males don\u0027t have a working androgen receptor."},{"Start":"00:30.165 ","End":"00:34.100","Text":"These patients, would they appear phenotypically female?"},{"Start":"00:34.100 ","End":"00:36.273","Text":"Would they appear phenotypically male,"},{"Start":"00:36.273 ","End":"00:39.335","Text":"but have underdeveloped secondary sex characteristics?"},{"Start":"00:39.335 ","End":"00:43.580","Text":"Would they appear phenotypically male but cannot produce sperm?"},{"Start":"00:43.580 ","End":"00:50.855","Text":"Or would they express both male and female sex characteristics?"},{"Start":"00:50.855 ","End":"00:57.304","Text":"If you remember, the gonads produce these steroid hormones,"},{"Start":"00:57.304 ","End":"01:00.600","Text":"androgens in particular, testosterone."},{"Start":"01:00.600 ","End":"01:04.640","Text":"What does that do? It allows for the development of"},{"Start":"01:04.640 ","End":"01:11.570","Text":"secondary sex characteristics and the production of sperm cells in males and females,"},{"Start":"01:11.570 ","End":"01:14.720","Text":"they do other things, but in this case we\u0027re talking about males."},{"Start":"01:14.720 ","End":"01:18.815","Text":"They allow for the development of secondary sex characteristics."},{"Start":"01:18.815 ","End":"01:23.510","Text":"In this case, patients would appear phenotypically"},{"Start":"01:23.510 ","End":"01:29.880","Text":"female because they didn\u0027t develop the male characteristics."}],"ID":30218},{"Watched":false,"Name":"Exercise 12","Duration":"50s","ChapterTopicVideoID":28695,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.390","Text":"A rise in blood glucose levels triggers release of insulin from the pancreas."},{"Start":"00:06.390 ","End":"00:10.110","Text":"This mechanism of hormone production is stimulated by;"},{"Start":"00:10.110 ","End":"00:13.319","Text":"humoral stimuli, hormonal stimuli,"},{"Start":"00:13.319 ","End":"00:17.400","Text":"neural stimuli, or negative stimuli."},{"Start":"00:17.400 ","End":"00:19.380","Text":"Well, if you remember,"},{"Start":"00:19.380 ","End":"00:24.105","Text":"humoral means chemical and if you remember,"},{"Start":"00:24.105 ","End":"00:33.960","Text":"we have a chemical change which regulates blood glucose level by glucagon and insulin."},{"Start":"00:33.960 ","End":"00:39.320","Text":"Glucose levels are chemicals which affect these things."},{"Start":"00:39.320 ","End":"00:44.960","Text":"Our answer to that is going to be humoral stimuli and not hormonal."},{"Start":"00:44.960 ","End":"00:47.120","Text":"Certainly not neural or not negative."},{"Start":"00:47.120 ","End":"00:50.100","Text":"It\u0027s going to be humoral."}],"ID":30219},{"Watched":false,"Name":"Exercise 13","Duration":"1m 27s","ChapterTopicVideoID":28696,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.080 ","End":"00:06.510","Text":"Which mechanism of hormonal stimulation would be affected if signaling"},{"Start":"00:06.510 ","End":"00:12.300","Text":"and hormone released from the hypothalamus was blocked?"},{"Start":"00:12.300 ","End":"00:15.810","Text":"Which mechanism hormonal stimulation will be affected of"},{"Start":"00:15.810 ","End":"00:19.995","Text":"signaling and hormone released from the hypothalamus was blocked?"},{"Start":"00:19.995 ","End":"00:22.430","Text":"Let\u0027s think about what the hypothalamus is,"},{"Start":"00:22.430 ","End":"00:25.205","Text":"would it be humoral and hormonal?"},{"Start":"00:25.205 ","End":"00:28.385","Text":"Hormonal and neural stimuli?"},{"Start":"00:28.385 ","End":"00:37.020","Text":"If you remember, the hypothalamus has both neural and hormonal side to them,"},{"Start":"00:37.020 ","End":"00:40.985","Text":"so maybe that\u0027s it, neural and humoral."},{"Start":"00:40.985 ","End":"00:42.980","Text":"Well, it\u0027s the hormones that are released,"},{"Start":"00:42.980 ","End":"00:44.690","Text":"so it\u0027s less likely"},{"Start":"00:44.690 ","End":"00:48.740","Text":"hormonal and negative stimuli that doesn\u0027t make that much sense. Let\u0027s see."},{"Start":"00:48.740 ","End":"00:50.930","Text":"It\u0027s not the first, not the third,"},{"Start":"00:50.930 ","End":"00:54.170","Text":"and not the fourth, it\u0027s hormonal and neural stimuli."},{"Start":"00:54.170 ","End":"00:58.905","Text":"If you remember the posterior pituitary."},{"Start":"00:58.905 ","End":"01:06.980","Text":"The posterior pituitary is innervated by nerve cells."},{"Start":"01:06.980 ","End":"01:09.260","Text":"We\u0027re talking about the hypothalamus here."},{"Start":"01:09.260 ","End":"01:19.805","Text":"While the anterior pituitary is affected by hormones."},{"Start":"01:19.805 ","End":"01:24.490","Text":"We have both hormonal and neural stimuli."},{"Start":"01:24.490 ","End":"01:26.810","Text":"Our answer here is going to be B."}],"ID":30220},{"Watched":false,"Name":"Exercise 14","Duration":"1m 10s","ChapterTopicVideoID":28697,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.420","Text":"A scientist hypothesizes that"},{"Start":"00:03.420 ","End":"00:08.055","Text":"the pancreas\u0027s hormone production is controlled by neural stimuli."},{"Start":"00:08.055 ","End":"00:15.930","Text":"This is a hypothesis by a scientist and we\u0027re talking about neural stimuli,"},{"Start":"00:15.930 ","End":"00:18.615","Text":"so it probably be something that happens pretty quickly."},{"Start":"00:18.615 ","End":"00:21.690","Text":"Which observation would support this hypothesis?"},{"Start":"00:21.690 ","End":"00:28.755","Text":"That insulin is produced in response to a sudden stress without a rise in blood glucose."},{"Start":"00:28.755 ","End":"00:30.080","Text":"Well, if it\u0027s sudden,"},{"Start":"00:30.080 ","End":"00:35.075","Text":"that is something that probably has to do with neural stimuli."},{"Start":"00:35.075 ","End":"00:40.340","Text":"That insulin is produced in response to a rise in glucagon levels."},{"Start":"00:40.340 ","End":"00:42.350","Text":"Well, that\u0027s a hormone,"},{"Start":"00:42.350 ","End":"00:43.640","Text":"it\u0027s not so fast."},{"Start":"00:43.640 ","End":"00:46.205","Text":"Beta cells express epinephrine receptors."},{"Start":"00:46.205 ","End":"00:51.500","Text":"Again, they\u0027re producing some receptors here that take some time."},{"Start":"00:51.500 ","End":"00:56.210","Text":"Insulin is produced in response to a rise in blood glucose in the brain,"},{"Start":"00:56.210 ","End":"00:57.890","Text":"again, that\u0027s a chemical."},{"Start":"00:57.890 ","End":"01:03.635","Text":"The fastest one would be this sudden stress, most likely neural."},{"Start":"01:03.635 ","End":"01:09.990","Text":"So A is probably the answer and indeed it is."}],"ID":30221},{"Watched":false,"Name":"Exercise 15","Duration":"39s","ChapterTopicVideoID":28698,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:02.070","Text":"This is another one you just have to remember,"},{"Start":"00:02.070 ","End":"00:06.000","Text":"which endocrine glands are associated with the kidneys?"},{"Start":"00:06.000 ","End":"00:08.820","Text":"Thyroid, pituitary, adrenal,"},{"Start":"00:08.820 ","End":"00:11.160","Text":"or gonads Well,"},{"Start":"00:11.160 ","End":"00:15.540","Text":"associated with the kidney that means they would have to be attached to them."},{"Start":"00:15.540 ","End":"00:18.060","Text":"If you remember, the thyroid is in the throat,"},{"Start":"00:18.060 ","End":"00:19.410","Text":"the pituitary is in the brain,"},{"Start":"00:19.410 ","End":"00:23.055","Text":"the gonads would be the ovaries or the testes,"},{"Start":"00:23.055 ","End":"00:26.910","Text":"so that leaves really just the adrenals."},{"Start":"00:26.910 ","End":"00:30.060","Text":"If you remember where the adrenals are,"},{"Start":"00:30.060 ","End":"00:38.880","Text":"indeed the adrenal gland is attached to the kidney."}],"ID":30222},{"Watched":false,"Name":"Exercise 16","Duration":"1m 11s","ChapterTopicVideoID":28682,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.470 ","End":"00:06.285","Text":"Which of the following hormones is not produced by the anterior pituitary?"},{"Start":"00:06.285 ","End":"00:11.130","Text":"Not produced by the anterior pituitary."},{"Start":"00:11.130 ","End":"00:13.470","Text":"Is it oxytocin, growth hormone,"},{"Start":"00:13.470 ","End":"00:17.310","Text":"prolactin or a thyroid-stimulating hormone?"},{"Start":"00:17.310 ","End":"00:21.645","Text":"Let\u0027s go to our charts and"},{"Start":"00:21.645 ","End":"00:27.930","Text":"see which hormones are associated with the anterior part of the pituitary."},{"Start":"00:27.930 ","End":"00:33.705","Text":"Growth hormone, prolactin, ACTH."},{"Start":"00:33.705 ","End":"00:38.745","Text":"What is that? It stimulates thyroid hormone release."},{"Start":"00:38.745 ","End":"00:43.425","Text":"FSH, LH, and MSH."},{"Start":"00:43.425 ","End":"00:46.970","Text":"Which of those is not being produced?"},{"Start":"00:46.970 ","End":"00:49.445","Text":"Well, we didn\u0027t mention oxytocin."},{"Start":"00:49.445 ","End":"00:51.390","Text":"We did mention growth hormone,"},{"Start":"00:51.390 ","End":"00:53.085","Text":"we did mention prolactin,"},{"Start":"00:53.085 ","End":"00:58.920","Text":"we did mention a hormone which stimulates the thyroid. Let\u0027s see."},{"Start":"00:58.920 ","End":"01:04.695","Text":"Oxytocin is produced by the posterior pituitary."},{"Start":"01:04.695 ","End":"01:10.080","Text":"Our answer then is going to be oxytocin."}],"ID":30206},{"Watched":false,"Name":"Exercise 17","Duration":"55s","ChapterTopicVideoID":28683,"CourseChapterTopicPlaylistID":286916,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:02.850","Text":"In this question, we\u0027re asked the following."},{"Start":"00:02.850 ","End":"00:09.645","Text":"Recent study suggest that blue light exposure can impact human circadian rhythms."},{"Start":"00:09.645 ","End":"00:16.700","Text":"That\u0027s things that are associated with the 24-hour clock circadian rhythms."},{"Start":"00:16.700 ","End":"00:20.580","Text":"This suggests the blue light disrupts the function of which gland?"},{"Start":"00:20.580 ","End":"00:24.330","Text":"Adrenal, pituitary, pineal, or thyroid."},{"Start":"00:24.330 ","End":"00:30.600","Text":"Well, let\u0027s recall what the pineal gland does."},{"Start":"00:30.600 ","End":"00:32.205","Text":"That\u0027s going to be our answer."},{"Start":"00:32.205 ","End":"00:35.880","Text":"The pineal gland, remember that\u0027s deep inside the brain,"},{"Start":"00:35.880 ","End":"00:39.705","Text":"produces melatonin, which is the sleep hormone,"},{"Start":"00:39.705 ","End":"00:43.710","Text":"that\u0027s the one that resets our circadian clock."},{"Start":"00:43.710 ","End":"00:48.110","Text":"Our answer to this question is that it\u0027s"},{"Start":"00:48.110 ","End":"00:51.020","Text":"the pineal gland that suggests"},{"Start":"00:51.020 ","End":"00:54.930","Text":"that blue light exposure can impact human circadian rhythms."}],"ID":30207}],"Thumbnail":null,"ID":286916}]

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