[{"Name":"Digestive Systems","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Carnivores Herbivores and Omnivores","Duration":"7m 44s","ChapterTopicVideoID":26425,"CourseChapterTopicPlaylistID":255409,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.060","Text":"Welcome back to our discussion of various systems in biological organisms."},{"Start":"00:06.060 ","End":"00:12.510","Text":"Here we\u0027re going to concentrate on digestive systems in different organisms,"},{"Start":"00:12.510 ","End":"00:15.840","Text":"especially our own in humans."},{"Start":"00:15.840 ","End":"00:20.250","Text":"But first let\u0027s see what the digestive system is needed for."},{"Start":"00:20.250 ","End":"00:25.080","Text":"First of all, all living organisms need nutrients to survive."},{"Start":"00:25.080 ","End":"00:30.030","Text":"The question is, where are those nutrients going to come from and how are"},{"Start":"00:30.030 ","End":"00:35.520","Text":"they going to be integrated at the end of the day in the organism itself?"},{"Start":"00:35.520 ","End":"00:38.450","Text":"Plants do it a particular way."},{"Start":"00:38.450 ","End":"00:43.265","Text":"They get most of their nutrients from photosynthesis."},{"Start":"00:43.265 ","End":"00:48.610","Text":"Photosynthesis. That is, they are going to take carbon from the air."},{"Start":"00:48.610 ","End":"00:52.130","Text":"They are going to take that carbon that was"},{"Start":"00:52.130 ","End":"00:55.235","Text":"in the form of carbon dioxide and integrate it"},{"Start":"00:55.235 ","End":"01:02.420","Text":"into sugars and the energy for that they take from light, that\u0027s photosynthesis."},{"Start":"01:02.420 ","End":"01:06.275","Text":"But most animals get their materials"},{"Start":"01:06.275 ","End":"01:10.625","Text":"and their energy from the consumption of other organisms."},{"Start":"01:10.625 ","End":"01:16.595","Text":"But they specialize and we\u0027ll see how that specialization works in a few minutes."},{"Start":"01:16.595 ","End":"01:20.240","Text":"In addition, there are particular required molecules."},{"Start":"01:20.240 ","End":"01:22.400","Text":"That is, there are amino acids."},{"Start":"01:22.400 ","End":"01:26.495","Text":"The amino acids are going to be the building blocks for proteins as you know,"},{"Start":"01:26.495 ","End":"01:27.935","Text":"there are the lipids,"},{"Start":"01:27.935 ","End":"01:31.280","Text":"the building blocks for fats, nucleotides,"},{"Start":"01:31.280 ","End":"01:34.040","Text":"building blocks for DNA,"},{"Start":"01:34.040 ","End":"01:37.760","Text":"RNA that is the genetic material and of course,"},{"Start":"01:37.760 ","End":"01:42.575","Text":"there are simple sugars which are the building blocks for the various carbohydrates."},{"Start":"01:42.575 ","End":"01:45.710","Text":"In general, in the food that we eat,"},{"Start":"01:45.710 ","End":"01:53.975","Text":"there are what we call protein whose basic components are amino acids, as we said,"},{"Start":"01:53.975 ","End":"01:56.300","Text":"the fats with a lipid components and"},{"Start":"01:56.300 ","End":"02:03.290","Text":"the complex carbohydrates that we find in that are made of the simple sugars."},{"Start":"02:03.290 ","End":"02:06.125","Text":"In order to get these particular materials,"},{"Start":"02:06.125 ","End":"02:09.710","Text":"we need to eat particular things."},{"Start":"02:09.710 ","End":"02:15.080","Text":"Our bodies are designed such that we can digest"},{"Start":"02:15.080 ","End":"02:20.720","Text":"particular food and make them or digest them into the building blocks,"},{"Start":"02:20.720 ","End":"02:24.530","Text":"so that we can then build up what we need for ourselves."},{"Start":"02:24.530 ","End":"02:28.670","Text":"An animal\u0027s diet must provide both the chemical energy,"},{"Start":"02:28.670 ","End":"02:30.965","Text":"the energy for cellular processes,"},{"Start":"02:30.965 ","End":"02:34.070","Text":"the building blocks, the organic building blocks for"},{"Start":"02:34.070 ","End":"02:37.955","Text":"the macromolecules and of course, essential nutrients."},{"Start":"02:37.955 ","End":"02:40.040","Text":"Some of these nutrients might be things"},{"Start":"02:40.040 ","End":"02:43.775","Text":"like vitamins and minerals and things of that sort."},{"Start":"02:43.775 ","End":"02:51.200","Text":"In general, we classify different organisms in 3 different categories."},{"Start":"02:51.200 ","End":"02:53.435","Text":"They can be herbivores,"},{"Start":"02:53.435 ","End":"02:55.985","Text":"that is, they eat only plants."},{"Start":"02:55.985 ","End":"03:01.700","Text":"They can be carnivores where they eat only other animals,"},{"Start":"03:01.700 ","End":"03:05.030","Text":"that\u0027s flesh, or they can do both."},{"Start":"03:05.030 ","End":"03:09.500","Text":"They can eat both plants and animals and those are called omnivores."},{"Start":"03:09.500 ","End":"03:13.940","Text":"There are many organisms that are also opportunistic feeders."},{"Start":"03:13.940 ","End":"03:18.055","Text":"That is, they are not really any of these things."},{"Start":"03:18.055 ","End":"03:21.350","Text":"100 percent, if there\u0027s something available,"},{"Start":"03:21.350 ","End":"03:23.465","Text":"they\u0027ll just eat it."},{"Start":"03:23.465 ","End":"03:25.730","Text":"That\u0027s more like an omnivore,"},{"Start":"03:25.730 ","End":"03:27.020","Text":"but as we\u0027ll see,"},{"Start":"03:27.020 ","End":"03:31.294","Text":"some organisms prefer plants and others prefer"},{"Start":"03:31.294 ","End":"03:35.990","Text":"animals and their bodies are designed for those particular things."},{"Start":"03:35.990 ","End":"03:38.435","Text":"Here\u0027s a list of carnivorous animals,"},{"Start":"03:38.435 ","End":"03:43.354","Text":"herbivorous organisms, and of course, we are omnivores."},{"Start":"03:43.354 ","End":"03:47.480","Text":"Yes, we\u0027re more similar to primates, to monkeys."},{"Start":"03:47.480 ","End":"03:50.450","Text":"Let\u0027s first look at herbivores."},{"Start":"03:50.450 ","End":"03:56.270","Text":"Herbivores, as we said, primarily eat plants."},{"Start":"03:56.270 ","End":"04:01.070","Text":"They can be vertebrates or invertebrates."},{"Start":"04:01.070 ","End":"04:06.305","Text":"Vertebrates of course, have a backbone like this horse and this iguana,"},{"Start":"04:06.305 ","End":"04:11.900","Text":"but this grasshopper does not have a backbone and it\u0027s an invertebrate,"},{"Start":"04:11.900 ","End":"04:14.334","Text":"but it is a herbivore."},{"Start":"04:14.334 ","End":"04:20.030","Text":"The digestion has to be capable of handling large amounts of plant material."},{"Start":"04:20.030 ","End":"04:26.105","Text":"Plant material is quite different than animal material and so the enzymes in"},{"Start":"04:26.105 ","End":"04:29.720","Text":"the digestive systems of these organisms must be able to"},{"Start":"04:29.720 ","End":"04:34.045","Text":"extract the necessary nutrients from plants."},{"Start":"04:34.045 ","End":"04:40.009","Text":"Now, herbivores are further classified as frugivores,"},{"Start":"04:40.009 ","End":"04:41.546","Text":"that eat fruit,"},{"Start":"04:41.546 ","End":"04:43.929","Text":"granivores that eat seeds,"},{"Start":"04:43.929 ","End":"04:50.912","Text":"nectivores that primarily suck nectar like this bird is doing here,"},{"Start":"04:50.912 ","End":"04:54.725","Text":"folivores that eat leaves like this,"},{"Start":"04:54.725 ","End":"04:57.110","Text":"caterpillar, eats the leaves."},{"Start":"04:57.110 ","End":"05:00.905","Text":"Different herbivores, eat different things."},{"Start":"05:00.905 ","End":"05:04.655","Text":"The primary food source of carnivores,"},{"Start":"05:04.655 ","End":"05:07.285","Text":"as we know, is animal flesh."},{"Start":"05:07.285 ","End":"05:11.410","Text":"They as well can be vertebrates or invertebrates,"},{"Start":"05:11.410 ","End":"05:15.500","Text":"but they are also classified into sub categories."},{"Start":"05:15.500 ","End":"05:18.320","Text":"They can be obligate carnivores."},{"Start":"05:18.320 ","End":"05:21.790","Text":"That is, they rely entirely on animal flesh,"},{"Start":"05:21.790 ","End":"05:26.715","Text":"they cannot eat plants."},{"Start":"05:26.715 ","End":"05:33.920","Text":"For instance, this bird here is a bird which hunts and only eat flesh."},{"Start":"05:33.920 ","End":"05:35.900","Text":"On the other hand, we can have"},{"Start":"05:35.900 ","End":"05:43.235","Text":"facultative carnivores like this bear over here that mostly eats flesh,"},{"Start":"05:43.235 ","End":"05:45.905","Text":"but it can also eat non-animal food."},{"Start":"05:45.905 ","End":"05:52.985","Text":"There\u0027s no clear line that differentiates between facultative carnivores and omnivores."},{"Start":"05:52.985 ","End":"05:56.980","Text":"Omnivores you remember are animals that eat both plants and animals,"},{"Start":"05:56.980 ","End":"06:00.380","Text":"these definitions are somewhat fuzzy."},{"Start":"06:00.380 ","End":"06:04.040","Text":"Now let\u0027s look at the subdivisions of the carnivores."},{"Start":"06:04.040 ","End":"06:07.460","Text":"They can be insectivores that eat mainly insects."},{"Start":"06:07.460 ","End":"06:10.790","Text":"Piscivores, P-I-A-S-C in Latin,"},{"Start":"06:10.790 ","End":"06:14.660","Text":"that\u0027s fish, eat mainly fish."},{"Start":"06:14.660 ","End":"06:17.930","Text":"They can be hyper carnivores."},{"Start":"06:17.930 ","End":"06:22.655","Text":"That is, more than 70 percent of what they eat is meat."},{"Start":"06:22.655 ","End":"06:25.475","Text":"For instance, these animals that you see here on the left,"},{"Start":"06:25.475 ","End":"06:27.649","Text":"they can be mesocarnivores,"},{"Start":"06:27.649 ","End":"06:31.370","Text":"they consume between 30 and 70 percent meat, in other words,"},{"Start":"06:31.370 ","End":"06:35.210","Text":"about half of what they eat is meat and ones that eat than that,"},{"Start":"06:35.210 ","End":"06:39.005","Text":"less than 30 percent, different animals."},{"Start":"06:39.005 ","End":"06:42.127","Text":"Let\u0027s say this bear or this raccoon,"},{"Start":"06:42.127 ","End":"06:44.995","Text":"those would be hypocarnivores."},{"Start":"06:44.995 ","End":"06:49.130","Text":"These are just definitions that help us discuss"},{"Start":"06:49.130 ","End":"06:52.880","Text":"what digestive systems these various animals"},{"Start":"06:52.880 ","End":"06:56.575","Text":"have to have in order to digest these various meats."},{"Start":"06:56.575 ","End":"07:01.925","Text":"Omnivores finally, after herbivores and carnivores."},{"Start":"07:01.925 ","End":"07:07.745","Text":"Omnivores remember, are going to eat both plant and animal derived food."},{"Start":"07:07.745 ","End":"07:09.860","Text":"In order to do that, they have to have"},{"Start":"07:09.860 ","End":"07:16.775","Text":"behavioral adaptation so they can actively consume both plants and animal materials."},{"Start":"07:16.775 ","End":"07:19.880","Text":"There\u0027s a physiological side of it that is to have"},{"Start":"07:19.880 ","End":"07:26.300","Text":"the right enzymes that are capable of digesting both plant and animal matter."},{"Start":"07:26.300 ","End":"07:31.820","Text":"Now some species eat primarily animal tissue at 1 stage of their lives,"},{"Start":"07:31.820 ","End":"07:34.100","Text":"but plant matter at another."},{"Start":"07:34.100 ","End":"07:44.610","Text":"They can also change how their digestive systems work as they get older."}],"ID":27332},{"Watched":false,"Name":"Different kinds of digestion systems","Duration":"9m 5s","ChapterTopicVideoID":26426,"CourseChapterTopicPlaylistID":255409,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.180","Text":"Hi. In the previous video,"},{"Start":"00:03.180 ","End":"00:06.975","Text":"we discussed what the digestive system needs to do,"},{"Start":"00:06.975 ","End":"00:12.660","Text":"which is to digest the food into the various components that the body can use,"},{"Start":"00:12.660 ","End":"00:14.520","Text":"either digested or ingested."},{"Start":"00:14.520 ","End":"00:17.820","Text":"Now, let\u0027s see what the various specializations are."},{"Start":"00:17.820 ","End":"00:22.240","Text":"There are different digestive systems."},{"Start":"00:22.790 ","End":"00:26.520","Text":"First, let\u0027s start out by looking at something which is very"},{"Start":"00:26.520 ","End":"00:29.550","Text":"simple, invertebrate digestive systems."},{"Start":"00:29.550 ","End":"00:33.435","Text":"They have what are called incomplete digestive tracts."},{"Start":"00:33.435 ","End":"00:36.915","Text":"Why is that? Because they have only a single opening,"},{"Start":"00:36.915 ","End":"00:42.315","Text":"only on 1 side where things go both in and out."},{"Start":"00:42.315 ","End":"00:46.129","Text":"There\u0027s the food enters through the mouth and there\u0027s a pharynx,"},{"Start":"00:46.129 ","End":"00:49.595","Text":"there\u0027s a muscle there that controls where things go in or out,"},{"Start":"00:49.595 ","End":"00:52.250","Text":"but the waste exits the same way."},{"Start":"00:52.250 ","End":"00:57.755","Text":"We have food going in and out."},{"Start":"00:57.755 ","End":"01:02.495","Text":"The waste exits through the mouth or through the same place."},{"Start":"01:02.495 ","End":"01:04.865","Text":"Through this muscular pharynx,"},{"Start":"01:04.865 ","End":"01:08.929","Text":"as we said, it lacks specialized parts,"},{"Start":"01:08.929 ","End":"01:10.385","Text":"as we\u0027ll see that later,"},{"Start":"01:10.385 ","End":"01:12.830","Text":"different parts of the digestive system in"},{"Start":"01:12.830 ","End":"01:16.280","Text":"higher organisms are specialized for different purposes."},{"Start":"01:16.280 ","End":"01:19.420","Text":"This lacks those specialized parts."},{"Start":"01:19.420 ","End":"01:23.030","Text":"Those are incomplete digestive tracts."},{"Start":"01:23.030 ","End":"01:28.600","Text":"Let\u0027s now look at ones that are complete digestive tracts."},{"Start":"01:28.600 ","End":"01:33.500","Text":"Invertebrate digestive systems can be complete as well,"},{"Start":"01:33.500 ","End":"01:36.005","Text":"like this worm, that is,"},{"Start":"01:36.005 ","End":"01:37.835","Text":"that there are 2 openings."},{"Start":"01:37.835 ","End":"01:45.290","Text":"There\u0027s a mouth where things go in and there is an anus or an exit."},{"Start":"01:45.290 ","End":"01:46.520","Text":"It\u0027s out the other way."},{"Start":"01:46.520 ","End":"01:49.805","Text":"That\u0027s 1 tube with an in and an out."},{"Start":"01:49.805 ","End":"01:51.410","Text":"Food enters to the mouth,"},{"Start":"01:51.410 ","End":"01:53.660","Text":"waste exits through the anus,"},{"Start":"01:53.660 ","End":"01:56.285","Text":"but there can be specialized regions that carry out"},{"Start":"01:56.285 ","End":"02:00.810","Text":"digestion in a step-by-step fashion as we\u0027ll see."},{"Start":"02:00.810 ","End":"02:05.090","Text":"This, for instance, is a monogastric digestive system."},{"Start":"02:05.090 ","End":"02:09.220","Text":"Gastric means stomach."},{"Start":"02:09.220 ","End":"02:11.955","Text":"Here\u0027s the stomach in this dog,"},{"Start":"02:11.955 ","End":"02:13.740","Text":"it is monogastric,"},{"Start":"02:13.740 ","End":"02:15.960","Text":"means it only has 1."},{"Start":"02:15.960 ","End":"02:17.945","Text":"In addition to that,"},{"Start":"02:17.945 ","End":"02:22.405","Text":"there\u0027s an oral cavity with the look at everything that the food encounters."},{"Start":"02:22.405 ","End":"02:24.035","Text":"We start out with the mouth,"},{"Start":"02:24.035 ","End":"02:25.100","Text":"the intake of the food,"},{"Start":"02:25.100 ","End":"02:27.590","Text":"their teeth to physically break down the food."},{"Start":"02:27.590 ","End":"02:32.885","Text":"There\u0027s saliva inside that mouth that contains enzymes primarily."},{"Start":"02:32.885 ","End":"02:35.420","Text":"This amylase, for instance,"},{"Start":"02:35.420 ","End":"02:39.605","Text":"in the dog contains this mucus and water and salts and cells and so on,"},{"Start":"02:39.605 ","End":"02:43.645","Text":"glycoproteins, but it mainly contains these enzymes to digest."},{"Start":"02:43.645 ","End":"02:45.260","Text":"Begin to digest the food."},{"Start":"02:45.260 ","End":"02:51.440","Text":"There are muscles in the esophagus which move the food down,"},{"Start":"02:51.440 ","End":"02:53.525","Text":"pushes the food down towards the stomach."},{"Start":"02:53.525 ","End":"02:57.170","Text":"In the stomach, we have further digestion with"},{"Start":"02:57.170 ","End":"03:01.295","Text":"other enzymes that are included in these gastric juices."},{"Start":"03:01.295 ","End":"03:03.620","Text":"It then moves to the small intestine"},{"Start":"03:03.620 ","End":"03:06.110","Text":"where there\u0027s further breakdown in different enzymes."},{"Start":"03:06.110 ","End":"03:11.225","Text":"There, the nutrients begin to be absorbed into the bloodstream."},{"Start":"03:11.225 ","End":"03:15.630","Text":"There is a movement from the small intestine into the bloodstream."},{"Start":"03:15.630 ","End":"03:18.604","Text":"Then finally in the large intestine,"},{"Start":"03:18.604 ","End":"03:20.795","Text":"there\u0027s lots of water in all this."},{"Start":"03:20.795 ","End":"03:24.970","Text":"The water is back absorbed into the blood system so that it\u0027s"},{"Start":"03:24.970 ","End":"03:30.940","Text":"dried down and the dryer waste material is compacted into feces."},{"Start":"03:30.940 ","End":"03:33.300","Text":"That\u0027s what we saw, for instance, in a dog,"},{"Start":"03:33.300 ","End":"03:35.160","Text":"but what about in birds,"},{"Start":"03:35.160 ","End":"03:36.630","Text":"in the avian system?"},{"Start":"03:36.630 ","End":"03:38.900","Text":"That\u0027s a bit different because for one thing,"},{"Start":"03:38.900 ","End":"03:42.155","Text":"they have very high metabolic rates and that requires"},{"Start":"03:42.155 ","End":"03:46.235","Text":"a very high efficiency of food processing and at the same time,"},{"Start":"03:46.235 ","End":"03:48.845","Text":"a low body weight."},{"Start":"03:48.845 ","End":"03:53.180","Text":"They typically, birds that is, have no teeth."},{"Start":"03:53.180 ","End":"03:56.375","Text":"Rather they have a beak that lowers the weight."},{"Start":"03:56.375 ","End":"03:59.780","Text":"Their stomach is not monogastric."},{"Start":"03:59.780 ","End":"04:02.517","Text":"It has 2 different chambers."},{"Start":"04:02.517 ","End":"04:06.050","Text":"One is called the proventriculus,"},{"Start":"04:06.050 ","End":"04:09.550","Text":"that\u0027s where you have digestion by gastric juices."},{"Start":"04:09.550 ","End":"04:11.120","Text":"Then you have the gizzard,"},{"Start":"04:11.120 ","End":"04:14.540","Text":"and that\u0027s a mechanical grinding place."},{"Start":"04:14.540 ","End":"04:18.045","Text":"Here you can see those 2 different parts"},{"Start":"04:18.045 ","End":"04:21.770","Text":"where the gizzard has muscles in it and sometimes birds, for instance,"},{"Start":"04:21.770 ","End":"04:25.820","Text":"will swallow stones or grit and things like that and that will"},{"Start":"04:25.820 ","End":"04:30.395","Text":"help grind the food since they have no teeth."},{"Start":"04:30.395 ","End":"04:34.490","Text":"Then the material does go into an intestine where"},{"Start":"04:34.490 ","End":"04:38.875","Text":"most of the chemical digestion and the absorption takes place just as we saw in the dog."},{"Start":"04:38.875 ","End":"04:45.810","Text":"Then there are food pellets which can come out the back and something which"},{"Start":"04:45.810 ","End":"04:52.990","Text":"is called cloaca and that\u0027s like the anus where the waste secretion occurs."},{"Start":"04:52.990 ","End":"04:56.090","Text":"That\u0027s birds. Now addition to birds,"},{"Start":"04:56.090 ","End":"04:59.330","Text":"we know about ruminants like cows."},{"Start":"04:59.330 ","End":"05:02.255","Text":"You know that they, for instance, chew their cud."},{"Start":"05:02.255 ","End":"05:03.800","Text":"Well, what a cow do,"},{"Start":"05:03.800 ","End":"05:07.775","Text":"they eat enormous amounts of cellulose."},{"Start":"05:07.775 ","End":"05:13.425","Text":"Cellulose is material that there is in large amounts in plants and"},{"Start":"05:13.425 ","End":"05:19.280","Text":"it requires special enzymes to be able to digest this into a usable material."},{"Start":"05:19.280 ","End":"05:21.050","Text":"In order to do that,"},{"Start":"05:21.050 ","End":"05:23.060","Text":"the cow, for instance,"},{"Start":"05:23.060 ","End":"05:24.185","Text":"or any of these ruminants,"},{"Start":"05:24.185 ","End":"05:27.930","Text":"are adapted to digest all of this cellulose."},{"Start":"05:27.930 ","End":"05:30.230","Text":"For one thing, they lack upper teeth,"},{"Start":"05:30.230 ","End":"05:34.460","Text":"but they have lower teeth and they have tongue and lips and they begin"},{"Start":"05:34.460 ","End":"05:39.135","Text":"to grind all of these plants that they eat."},{"Start":"05:39.135 ","End":"05:43.770","Text":"Then it goes into 4 different stomachs."},{"Start":"05:43.770 ","End":"05:46.175","Text":"Not 2 as we saw earlier in the bird."},{"Start":"05:46.175 ","End":"05:49.850","Text":"There\u0027s one called the rumen and then the reticulum and those"},{"Start":"05:49.850 ","End":"05:54.060","Text":"contain bacteria prokaryotes,"},{"Start":"05:54.060 ","End":"05:55.830","Text":"they do a lot of the heavy lifting,"},{"Start":"05:55.830 ","End":"05:57.975","Text":"they do a lot of the digestion."},{"Start":"05:57.975 ","End":"05:59.475","Text":"As well as protists,"},{"Start":"05:59.475 ","End":"06:02.620","Text":"they digest this cellulose fiber,"},{"Start":"06:02.620 ","End":"06:06.705","Text":"producing enzymes that the cow itself can\u0027t produce."},{"Start":"06:06.705 ","End":"06:09.590","Text":"Then this cud, what we call cud,"},{"Start":"06:09.590 ","End":"06:13.430","Text":"is regurgitated from these 2 stomachs and is"},{"Start":"06:13.430 ","End":"06:18.085","Text":"chewed back again in the mouth and it\u0027s swallowed again."},{"Start":"06:18.085 ","End":"06:22.610","Text":"Then it goes into this region called the omasum,"},{"Start":"06:22.610 ","End":"06:27.605","Text":"which removes the water similar to what the large intestine did"},{"Start":"06:27.605 ","End":"06:33.205","Text":"in the dog and then the cud passes into the abomasum,"},{"Start":"06:33.205 ","End":"06:38.300","Text":"which has more enzymes that are produced by"},{"Start":"06:38.300 ","End":"06:44.950","Text":"the animal in order to get better even more nutrients out of the food."},{"Start":"06:44.950 ","End":"06:46.935","Text":"That was ruminants."},{"Start":"06:46.935 ","End":"06:51.065","Text":"Those are cows and sheep and goats and things like that."},{"Start":"06:51.065 ","End":"06:55.265","Text":"But there are also pseudoruminantslike like horses,"},{"Start":"06:55.265 ","End":"06:57.380","Text":"and they don\u0027t have 4 chambers,"},{"Start":"06:57.380 ","End":"07:00.480","Text":"they have 3 chambered stomachs."},{"Start":"07:00.480 ","End":"07:05.810","Text":"It\u0027s 1 stomach, but it has 3 different chambers in it,"},{"Start":"07:05.810 ","End":"07:12.090","Text":"unlike the 4 stomachs that we saw in the ruminants."},{"Start":"07:13.160 ","End":"07:18.450","Text":"Here are the 4 stomachs that were in the ruminants and in the pseudoruminants,"},{"Start":"07:18.450 ","End":"07:20.310","Text":"we only have 1 stomach,"},{"Start":"07:20.310 ","End":"07:22.070","Text":"but it has 3 different chambers."},{"Start":"07:22.070 ","End":"07:28.339","Text":"In addition, the large intestine has a region called the cecum,"},{"Start":"07:28.339 ","End":"07:31.670","Text":"and it contains many microorganisms,"},{"Start":"07:31.670 ","End":"07:35.450","Text":"just like the cow did to help digest plant materials."},{"Start":"07:35.450 ","End":"07:40.600","Text":"That\u0027s the site where the roughage is fermented and digested."},{"Start":"07:40.600 ","End":"07:44.475","Text":"It has no rumen, this pseudoruminant,"},{"Start":"07:44.475 ","End":"07:46.800","Text":"but it does have the omasum,"},{"Start":"07:46.800 ","End":"07:49.505","Text":"the abomasum and the reticulum."},{"Start":"07:49.505 ","End":"07:54.450","Text":"The reticulum is like the intestine where things are absorbed."},{"Start":"07:54.450 ","End":"07:58.415","Text":"It\u0027s a similar system but not quite the same."},{"Start":"07:58.415 ","End":"08:03.275","Text":"We\u0027re talking here about horses, donkeys, and camels."},{"Start":"08:03.275 ","End":"08:08.770","Text":"Now the final adaptation that we want to talk about is the initial chewing."},{"Start":"08:08.770 ","End":"08:14.600","Text":"Different animals that have to deal with different food, like omnivores,"},{"Start":"08:14.600 ","End":"08:21.140","Text":"carnivores or herbivores have to be able to chew the food differently so their dentition,"},{"Start":"08:21.140 ","End":"08:23.580","Text":"that\u0027s their teeth, differ."},{"Start":"08:23.580 ","End":"08:26.900","Text":"In omnivores, they\u0027re various specializations and they"},{"Start":"08:26.900 ","End":"08:31.455","Text":"can accommodate both vegetation and meat. There\u0027s the omnivores."},{"Start":"08:31.455 ","End":"08:35.420","Text":"The herbivores have these incisors for can clip things off,"},{"Start":"08:35.420 ","End":"08:40.355","Text":"and they have premolars and molars for grinding."},{"Start":"08:40.355 ","End":"08:42.350","Text":"Carnivores, on the other hand,"},{"Start":"08:42.350 ","End":"08:49.070","Text":"have to be able to have pointed-in sizes to be able to tear the meat that they\u0027re eating."},{"Start":"08:49.070 ","End":"08:53.240","Text":"They have large incisors and what we call canines and"},{"Start":"08:53.240 ","End":"08:57.980","Text":"they share pieces that are small enough to be able to swallow."},{"Start":"08:57.980 ","End":"08:59.585","Text":"In the next videos,"},{"Start":"08:59.585 ","End":"09:05.340","Text":"we\u0027ll look at how we humans handle food in our digestive system."}],"ID":27333},{"Watched":false,"Name":"Mouth to stomach in humans","Duration":"6m 13s","ChapterTopicVideoID":26423,"CourseChapterTopicPlaylistID":255409,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.030","Text":"Welcome back to our video that discusses digestive systems."},{"Start":"00:06.030 ","End":"00:10.320","Text":"We\u0027ve been discussing the digestive systems in various organisms,"},{"Start":"00:10.320 ","End":"00:13.140","Text":"and now it\u0027s time to get to us,"},{"Start":"00:13.140 ","End":"00:16.650","Text":"to the human digestive tract."},{"Start":"00:16.650 ","End":"00:26.210","Text":"The human digestive tract is a complete tract that goes from one end to the other."},{"Start":"00:26.210 ","End":"00:29.000","Text":"It\u0027s called an alimentary canal."},{"Start":"00:29.000 ","End":"00:31.460","Text":"This canal which starts, of course,"},{"Start":"00:31.460 ","End":"00:34.940","Text":"in the mouth and ends up in the anus."},{"Start":"00:34.940 ","End":"00:37.820","Text":"It\u0027s part of a tube-within-a-tube body plan."},{"Start":"00:37.820 ","End":"00:39.350","Text":"That is, there\u0027s a tube,"},{"Start":"00:39.350 ","End":"00:44.495","Text":"the food goes into the mouth through a tube and so on, out the other end,"},{"Start":"00:44.495 ","End":"00:47.930","Text":"that you can view that tube as being within"},{"Start":"00:47.930 ","End":"00:51.890","Text":"a greater tube that contains the cells of the body."},{"Start":"00:51.890 ","End":"00:55.280","Text":"It\u0027s called a tube-within-a-tube body plan."},{"Start":"00:55.280 ","End":"00:58.765","Text":"It begins, of course, with the mouth and ends with the anus, as we\u0027ve said."},{"Start":"00:58.765 ","End":"01:02.425","Text":"The digestion is entirely extracellular."},{"Start":"01:02.425 ","End":"01:09.220","Text":"That means that it occurs within this tube and not inside cells."},{"Start":"01:09.220 ","End":"01:13.570","Text":"The enzymes that do this digestion are"},{"Start":"01:13.570 ","End":"01:18.685","Text":"secreted by either the wall of the digestive tract as we\u0027ll see,"},{"Start":"01:18.685 ","End":"01:21.625","Text":"or by nearby glands."},{"Start":"01:21.625 ","End":"01:26.360","Text":"But the digestion itself takes place inside the tube."},{"Start":"01:26.360 ","End":"01:31.060","Text":"Let\u0027s start now with the mouth or the oral cavity."},{"Start":"01:31.060 ","End":"01:32.590","Text":"The oral cavity, of course,"},{"Start":"01:32.590 ","End":"01:35.830","Text":"is the point of entry of the food into the digestive system."},{"Start":"01:35.830 ","End":"01:38.470","Text":"That\u0027s where the food is first broken down into"},{"Start":"01:38.470 ","End":"01:42.405","Text":"smaller particles by chewing or mastication."},{"Start":"01:42.405 ","End":"01:43.730","Text":"That\u0027s what our teeth are for,"},{"Start":"01:43.730 ","End":"01:48.452","Text":"is to grind the food into smaller pieces,"},{"Start":"01:48.452 ","End":"01:54.200","Text":"then the chemical digestion begins by enzymes that are inside the saliva,"},{"Start":"01:54.200 ","End":"01:59.420","Text":"and that saliva is produced by the salivary glands that we\u0027ll see in a minute."},{"Start":"01:59.420 ","End":"02:00.815","Text":"Now, what is the saliva?"},{"Start":"02:00.815 ","End":"02:05.180","Text":"The saliva is a watery substance, we all know that."},{"Start":"02:05.180 ","End":"02:11.146","Text":"It\u0027s produced in glands that are just outside the mouth really,"},{"Start":"02:11.146 ","End":"02:13.159","Text":"in many different animals."},{"Start":"02:13.159 ","End":"02:17.790","Text":"Now, let\u0027s look at saliva or the saliva glands."},{"Start":"02:17.790 ","End":"02:23.430","Text":"There are 3 major saliva glands."},{"Start":"02:23.430 ","End":"02:28.870","Text":"There\u0027s the parotid, there\u0027s the submandibular,"},{"Start":"02:28.870 ","End":"02:32.195","Text":"and there is the sublingual."},{"Start":"02:32.195 ","End":"02:37.510","Text":"As you can see, each of these is found in a different place"},{"Start":"02:37.510 ","End":"02:43.775","Text":"inside the face or just around the mouth."},{"Start":"02:43.775 ","End":"02:47.885","Text":"You can see it on the front view and on the side view that we have there."},{"Start":"02:47.885 ","End":"02:51.110","Text":"The saliva that\u0027s produced in these various glands contains,"},{"Start":"02:51.110 ","End":"02:53.045","Text":"of course, a mucus that\u0027s the liquid,"},{"Start":"02:53.045 ","End":"02:55.535","Text":"it includes immunoglobulins,"},{"Start":"02:55.535 ","End":"02:58.490","Text":"those are antibodies, and lysozymes."},{"Start":"02:58.490 ","End":"03:04.800","Text":"Lysozymes are enzymes that begin to digest things like bacteria,"},{"Start":"03:04.800 ","End":"03:06.050","Text":"and cells and things like that,"},{"Start":"03:06.050 ","End":"03:07.670","Text":"begins to break them apart."},{"Start":"03:07.670 ","End":"03:12.980","Text":"There\u0027s amylase which is an enzyme that digests carbohydrates,"},{"Start":"03:12.980 ","End":"03:17.245","Text":"and lipase, an enzyme that digests lipids."},{"Start":"03:17.245 ","End":"03:20.262","Text":"Looking further down the throat,"},{"Start":"03:20.262 ","End":"03:22.860","Text":"so here\u0027s the mouth and looking further inside,"},{"Start":"03:22.860 ","End":"03:26.770","Text":"we get to the pharynx."},{"Start":"03:26.810 ","End":"03:29.382","Text":"Now, what is the pharynx?"},{"Start":"03:29.382 ","End":"03:33.620","Text":"The pharynx is this opening that is behind the mouth,"},{"Start":"03:33.620 ","End":"03:37.655","Text":"and there\u0027s a soft palate up here which"},{"Start":"03:37.655 ","End":"03:42.755","Text":"closes off this region to the sinuses or the nasal cavity."},{"Start":"03:42.755 ","End":"03:47.255","Text":"It opens going down now into 2 passageways."},{"Start":"03:47.255 ","End":"03:51.363","Text":"There\u0027s the trachea that\u0027s down this way,"},{"Start":"03:51.363 ","End":"03:54.788","Text":"that\u0027s the trachea that\u0027s going to go into the lungs,"},{"Start":"03:54.788 ","End":"03:57.545","Text":"and there is the esophagus,"},{"Start":"03:57.545 ","End":"04:02.105","Text":"that\u0027s where the food is going to go and that leads to the stomach."},{"Start":"04:02.105 ","End":"04:05.360","Text":"Now, of course, there are valves that close,"},{"Start":"04:05.360 ","End":"04:10.280","Text":"1 or the other passage so that we don\u0027t get food into our lungs,"},{"Start":"04:10.280 ","End":"04:14.560","Text":"and that is the epiglottis."},{"Start":"04:14.560 ","End":"04:18.960","Text":"Epiglottis, that\u0027s this area over here,"},{"Start":"04:18.960 ","End":"04:23.735","Text":"it can go up and down to close the glottis or"},{"Start":"04:23.735 ","End":"04:30.920","Text":"the trachea so that the food goes down into our esophagus when we swallow."},{"Start":"04:30.920 ","End":"04:34.000","Text":"Let\u0027s next look into the esophagus."},{"Start":"04:34.000 ","End":"04:39.635","Text":"A bunch of food or bolus of food can"},{"Start":"04:39.635 ","End":"04:45.605","Text":"go into this esophagus that is connected to the mouth."},{"Start":"04:45.605 ","End":"04:50.345","Text":"The mouth is on the top and the stomach is on the other side."},{"Start":"04:50.345 ","End":"04:53.990","Text":"The food passes through the esophagus after it\u0027s swallowed and"},{"Start":"04:53.990 ","End":"04:57.875","Text":"it moves by a process called peristalsis."},{"Start":"04:57.875 ","End":"05:05.360","Text":"Peristalsis is this contraction and you can see that moves the food down."},{"Start":"05:05.360 ","End":"05:10.165","Text":"The esophagus contracts above the food and relaxes below it,"},{"Start":"05:10.165 ","End":"05:15.185","Text":"moving this ball down and forward towards the stomach."},{"Start":"05:15.185 ","End":"05:18.442","Text":"This movement is involuntary,"},{"Start":"05:18.442 ","End":"05:20.600","Text":"we don\u0027t have control over this."},{"Start":"05:20.600 ","End":"05:24.530","Text":"Now once the food goes through the esophagus,"},{"Start":"05:24.530 ","End":"05:31.040","Text":"it goes into the stomach through a gastroesophageal sphincter."},{"Start":"05:31.040 ","End":"05:34.370","Text":"A sphincter, this is something which can open and close,"},{"Start":"05:34.370 ","End":"05:39.935","Text":"that can close keeping food from traveling up the esophagus."},{"Start":"05:39.935 ","End":"05:41.910","Text":"That\u0027s vomiting or throwing up,"},{"Start":"05:41.910 ","End":"05:44.970","Text":"we don\u0027t want that, normally."},{"Start":"05:44.970 ","End":"05:48.655","Text":"But we do want it open so the food can come down."},{"Start":"05:48.655 ","End":"05:54.230","Text":"The sphincter then can open to allow food down,"},{"Start":"05:54.230 ","End":"05:57.140","Text":"but should close in order to keep"},{"Start":"05:57.140 ","End":"06:01.370","Text":"the food or the material that\u0027s inside the stomach from going back up."},{"Start":"06:01.370 ","End":"06:08.470","Text":"If it doesn\u0027t do that, we get reflux or we get something called heartburn,"},{"Start":"06:08.470 ","End":"06:13.620","Text":"when the digestive juices escape into the esophagus."}],"ID":27330},{"Watched":false,"Name":"Stomach to anus in humans","Duration":"8m 28s","ChapterTopicVideoID":26424,"CourseChapterTopicPlaylistID":255409,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.053","Text":"Now we\u0027ll discuss what happens to the food when it gets into the stomach,"},{"Start":"00:06.053 ","End":"00:08.040","Text":"where of course we\u0027re talking about"},{"Start":"00:08.040 ","End":"00:12.645","Text":"the digestive systems and particularly what happens in humans."},{"Start":"00:12.645 ","End":"00:14.820","Text":"We\u0027re now in the stomach."},{"Start":"00:14.820 ","End":"00:17.685","Text":"What we see is that the stomach is"},{"Start":"00:17.685 ","End":"00:23.355","Text":"a sack-like organ that secretes various gastric digestive juices."},{"Start":"00:23.355 ","End":"00:26.520","Text":"We said before that there were some enzymes that"},{"Start":"00:26.520 ","End":"00:29.520","Text":"digest and begin to digest the food in the mouth but"},{"Start":"00:29.520 ","End":"00:36.615","Text":"this digestion continues now in the stomach and it does it at a very low pH,"},{"Start":"00:36.615 ","End":"00:40.865","Text":"between 1.5 and 2.5 it\u0027s extremely acidic."},{"Start":"00:40.865 ","End":"00:45.065","Text":"This facilitates the chemical breakdown of some of the foods,"},{"Start":"00:45.065 ","End":"00:47.465","Text":"in particular the proteins."},{"Start":"00:47.465 ","End":"00:50.360","Text":"We have the enzyme called pepsin,"},{"Start":"00:50.360 ","End":"00:54.050","Text":"which is a hydrolytic enzyme that acts on proteins,"},{"Start":"00:54.050 ","End":"00:59.105","Text":"as we said, that produces peptides that breaks down the proteins into peptides."},{"Start":"00:59.105 ","End":"01:02.360","Text":"Its first synthesized the pepsin, that is,"},{"Start":"01:02.360 ","End":"01:06.440","Text":"in the inactive form of pepsinogen that the reason for that,"},{"Start":"01:06.440 ","End":"01:10.055","Text":"that of course this enzyme digests proteins."},{"Start":"01:10.055 ","End":"01:11.685","Text":"Cells are made of proteins,"},{"Start":"01:11.685 ","End":"01:15.140","Text":"so in order to have the cells that produce them,"},{"Start":"01:15.140 ","End":"01:16.459","Text":"to be protected,"},{"Start":"01:16.459 ","End":"01:20.990","Text":"its first made in an inactive form called pepsinogen."},{"Start":"01:20.990 ","End":"01:29.300","Text":"Let\u0027s look briefly at what the lining of the stomach looks like in a larger picture here."},{"Start":"01:29.300 ","End":"01:33.950","Text":"We see that there are these channels that are inside the lining of the stomach."},{"Start":"01:33.950 ","End":"01:35.495","Text":"Each of these channels,"},{"Start":"01:35.495 ","End":"01:40.595","Text":"there are cells blown up over here and there are particular cells"},{"Start":"01:40.595 ","End":"01:46.085","Text":"called the parietal cells and there are other cells called chief cells."},{"Start":"01:46.085 ","End":"01:50.240","Text":"This chief cells make the pepsinogen,"},{"Start":"01:50.240 ","End":"01:57.289","Text":"which then is turned into pepsin as an active enzyme by the HCl,"},{"Start":"01:57.289 ","End":"02:02.210","Text":"the hydrochloric acid that\u0027s produced by the parietal cell outside the cells."},{"Start":"02:02.210 ","End":"02:09.680","Text":"Then that pepsin will move up through the epithelium of the stomach and into"},{"Start":"02:09.680 ","End":"02:12.740","Text":"the stomach cavity where it does its job"},{"Start":"02:12.740 ","End":"02:18.743","Text":"of hydrolyzing the proteins that are in the food."},{"Start":"02:18.743 ","End":"02:26.105","Text":"What\u0027s left afterwards is this mixture of food and gastric juices that we call chyme."},{"Start":"02:26.105 ","End":"02:28.425","Text":"This, after a while,"},{"Start":"02:28.425 ","End":"02:33.710","Text":"will pass from the stomach into the small intestine."},{"Start":"02:33.710 ","End":"02:40.300","Text":"Now, at the bottom of the stomach we have the pyloric sphincter."},{"Start":"02:40.300 ","End":"02:44.210","Text":"So between the stomach and the beginning of the intestine or"},{"Start":"02:44.210 ","End":"02:50.615","Text":"the duodenum is another sphincter called the pyloric sphincter."},{"Start":"02:50.615 ","End":"02:52.790","Text":"It regulates the movement of the chyme from"},{"Start":"02:52.790 ","End":"02:55.400","Text":"the stomach into the small intestine and it of course"},{"Start":"02:55.400 ","End":"03:00.680","Text":"remains closed most of the time while the stomach mixes food with gastric juices."},{"Start":"03:00.680 ","End":"03:04.220","Text":"But after the stomach has completed its digestion,"},{"Start":"03:04.220 ","End":"03:06.785","Text":"it briefly opens and permits"},{"Start":"03:06.785 ","End":"03:10.730","Text":"small amounts of chyme to pass into the small intestine and this"},{"Start":"03:10.730 ","End":"03:17.945","Text":"happens over a period of about 30 minutes to an hour after the stomach has become filled."},{"Start":"03:17.945 ","End":"03:23.050","Text":"Let\u0027s continue now to see what happens in the small intestine."},{"Start":"03:23.050 ","End":"03:30.425","Text":"So the small intestine then is the longest compartment of the alimentary canal."},{"Start":"03:30.425 ","End":"03:34.595","Text":"This is where the digestion of the proteins and the fats"},{"Start":"03:34.595 ","End":"03:39.110","Text":"and the carbohydrates that was started earlier is completed."},{"Start":"03:39.110 ","End":"03:45.500","Text":"It\u0027s responsible for most of the enzymatic hydrolysis of the macromolecules."},{"Start":"03:45.500 ","End":"03:50.110","Text":"In addition, it\u0027s also responsible for absorbing"},{"Start":"03:50.110 ","End":"03:56.945","Text":"the nutrients into the bloodstream so that they can be spread around the body."},{"Start":"03:56.945 ","End":"03:59.265","Text":"To do this, there are villi."},{"Start":"03:59.265 ","End":"04:00.725","Text":"These are called villi,"},{"Start":"04:00.725 ","End":"04:05.150","Text":"these little things that are extruded from the side of"},{"Start":"04:05.150 ","End":"04:10.055","Text":"the intestine and microvilli that are on the surface of the cells."},{"Start":"04:10.055 ","End":"04:14.840","Text":"Those increase the surface area of the intestine,"},{"Start":"04:14.840 ","End":"04:18.049","Text":"particularly so there can be better absorption."},{"Start":"04:18.049 ","End":"04:23.090","Text":"They absorbed nutrients then are carried through the bloodstream first to"},{"Start":"04:23.090 ","End":"04:28.100","Text":"the liver where they are checked and then detoxified if need be."},{"Start":"04:28.100 ","End":"04:32.270","Text":"Let\u0027s look now at the different parts of the small intestine."},{"Start":"04:32.270 ","End":"04:34.655","Text":"We mentioned already the duodenum."},{"Start":"04:34.655 ","End":"04:38.600","Text":"This is where there\u0027s a neutralization first of the gastric juices,"},{"Start":"04:38.600 ","End":"04:41.690","Text":"remember the gastric juices in the stomach were very"},{"Start":"04:41.690 ","End":"04:45.815","Text":"acidic and then there is absorption of water,"},{"Start":"04:45.815 ","End":"04:49.264","Text":"of electrolytes that\u0027s the salts, and various nutrients."},{"Start":"04:49.264 ","End":"04:54.350","Text":"This begins at the beginning of the small intestine."},{"Start":"04:54.350 ","End":"04:58.924","Text":"The next piece of the small intestine is called jejunum."},{"Start":"04:58.924 ","End":"05:03.860","Text":"That\u0027s where the bulk of the chemical digestion and nutrient absorption occurs."},{"Start":"05:03.860 ","End":"05:08.234","Text":"That\u0027s the central part of the small intestine."},{"Start":"05:08.234 ","End":"05:11.330","Text":"Finally, the last part that\u0027s"},{"Start":"05:11.330 ","End":"05:14.537","Text":"going to connect with the large intestine is called the ilium"},{"Start":"05:14.537 ","End":"05:17.360","Text":"and that\u0027s where salts and vitamins that were"},{"Start":"05:17.360 ","End":"05:21.380","Text":"in the food are absorbed into the bloodstream."},{"Start":"05:21.380 ","End":"05:29.206","Text":"What\u0027s not been digested then goes to the colon or the large intestine,"},{"Start":"05:29.206 ","End":"05:35.675","Text":"and that\u0027s where the water primarily is going to be removed from this mix."},{"Start":"05:35.675 ","End":"05:38.855","Text":"We all know that there is something called the appendix."},{"Start":"05:38.855 ","End":"05:43.280","Text":"It\u0027s a little piece here that it\u0027s the end of the cecum"},{"Start":"05:43.280 ","End":"05:48.635","Text":"and it secretes no enzymes and really has an insignificant role in immunity."},{"Start":"05:48.635 ","End":"05:52.985","Text":"It\u0027s some sort of a vestige evidently in evolutionary vestige."},{"Start":"05:52.985 ","End":"05:55.790","Text":"Finally, let\u0027s look at the large intestine."},{"Start":"05:55.790 ","End":"05:58.220","Text":"So the large intestine, as I mentioned,"},{"Start":"05:58.220 ","End":"06:02.090","Text":"reabsorbs the water from the undigested food material and then"},{"Start":"06:02.090 ","End":"06:07.385","Text":"processes the waste material eventually by pushing it out through the anus."},{"Start":"06:07.385 ","End":"06:11.060","Text":"Now, it too is divided into 3 parts."},{"Start":"06:11.060 ","End":"06:17.465","Text":"There\u0027s the cecum, the part that is closest to the ileum"},{"Start":"06:17.465 ","End":"06:23.855","Text":"of the small intestine and there is fermentation that occurs in this area,"},{"Start":"06:23.855 ","End":"06:29.045","Text":"not too different than we saw in cows or in horses."},{"Start":"06:29.045 ","End":"06:32.810","Text":"There\u0027s fermentation of plant material by bacteria"},{"Start":"06:32.810 ","End":"06:37.880","Text":"that were not digested higher up in the canal."},{"Start":"06:37.880 ","End":"06:40.630","Text":"There\u0027s the extraction of water and"},{"Start":"06:40.630 ","End":"06:45.320","Text":"the ascending colon and mineral salts and the undigested food,"},{"Start":"06:45.320 ","End":"06:50.480","Text":"and then finally, there is storage of these materials,"},{"Start":"06:50.480 ","End":"06:54.470","Text":"defecation before it is removed."},{"Start":"06:54.470 ","End":"06:57.560","Text":"Undigested is removed through the anus."},{"Start":"06:57.560 ","End":"07:01.040","Text":"Lastly, let\u0027s look at accessory organs"},{"Start":"07:01.040 ","End":"07:05.420","Text":"that produce other enzymes that we have not discussed before."},{"Start":"07:05.420 ","End":"07:08.675","Text":"There is the liver, which is the largest internal organ,"},{"Start":"07:08.675 ","End":"07:11.134","Text":"which is sits in the abdomen."},{"Start":"07:11.134 ","End":"07:14.180","Text":"It\u0027s responsible for producing enzymes that digest"},{"Start":"07:14.180 ","End":"07:18.215","Text":"fats and that detoxifies the blood, as we said before."},{"Start":"07:18.215 ","End":"07:20.300","Text":"It processes vitamins and fats,"},{"Start":"07:20.300 ","End":"07:22.280","Text":"synthesizes many plasma proteins,"},{"Start":"07:22.280 ","End":"07:25.850","Text":"and interconverts many organic molecules from"},{"Start":"07:25.850 ","End":"07:30.020","Text":"one form to another so they can be better used by the body."},{"Start":"07:30.020 ","End":"07:34.191","Text":"The pancreas which sits below the liver"},{"Start":"07:34.191 ","End":"07:39.295","Text":"secretes digestive juices that contain other enzymes,"},{"Start":"07:39.295 ","End":"07:42.640","Text":"and also high levels of bicarbonate."},{"Start":"07:42.640 ","End":"07:48.080","Text":"That bicarbonate neutralizes the acidic chyme as it comes out of"},{"Start":"07:48.080 ","End":"07:51.080","Text":"the stomach and in addition it produces a variety of enzymes for"},{"Start":"07:51.080 ","End":"07:55.085","Text":"digestion of protein and carbohydrates."},{"Start":"07:55.085 ","End":"08:00.110","Text":"Now, the liver sends its juices and they are called bile,"},{"Start":"08:00.110 ","End":"08:02.960","Text":"first through the gallbladder,"},{"Start":"08:02.960 ","End":"08:11.120","Text":"which is a sac that aids the liver by storing this bile and concentrating the bile salts."},{"Start":"08:11.120 ","End":"08:15.065","Text":"The bile, the juices from the liver,"},{"Start":"08:15.065 ","End":"08:24.290","Text":"sit in this sac and they then are secreted into duodenum when necessary."},{"Start":"08:24.290 ","End":"08:29.310","Text":"That completes our discussion of digestion in humans."}],"ID":27331}],"Thumbnail":null,"ID":255409},{"Name":"Nutrition and Energy Production","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Nutrition and Energy Production","Duration":"7m 6s","ChapterTopicVideoID":26420,"CourseChapterTopicPlaylistID":255410,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:02.640","Text":"All right."},{"Start":"00:02.640 ","End":"00:06.180","Text":"We\u0027ve discussed the digestive systems of various animals and"},{"Start":"00:06.180 ","End":"00:11.325","Text":"humans and now it\u0027s time to look into what goes into that digestive system."},{"Start":"00:11.325 ","End":"00:18.870","Text":"That is nutrition and what are the requirements for nutrition and energy production."},{"Start":"00:18.870 ","End":"00:22.290","Text":"First of all, of course we know that animal diets vary"},{"Start":"00:22.290 ","End":"00:25.760","Text":"substantially and the system has to be"},{"Start":"00:25.760 ","End":"00:32.995","Text":"able to get the right balance of nutrients in order to make the organism live."},{"Start":"00:32.995 ","End":"00:38.870","Text":"First of all it must provide chemical energy for cellular processes."},{"Start":"00:38.870 ","End":"00:42.110","Text":"It must contain the organic building blocks for"},{"Start":"00:42.110 ","End":"00:47.370","Text":"the various macromolecules that the organism needs to make like it\u0027s DNA for instance."},{"Start":"00:47.370 ","End":"00:50.870","Text":"Of course there are the essential nutrients that are"},{"Start":"00:50.870 ","End":"00:54.824","Text":"necessary for making all other systems work,"},{"Start":"00:54.824 ","End":"00:56.450","Text":"like let\u0027s say, vitamins,"},{"Start":"00:56.450 ","End":"00:58.640","Text":"minerals, and things like that."},{"Start":"00:58.640 ","End":"01:07.370","Text":"The diet must be balanced to provide all these various components in the right amounts."},{"Start":"01:07.370 ","End":"01:09.830","Text":"What are the organic precursors?"},{"Start":"01:09.830 ","End":"01:11.570","Text":"That\u0027s organic molecules, of course,"},{"Start":"01:11.570 ","End":"01:13.685","Text":"are ones that contain carbon."},{"Start":"01:13.685 ","End":"01:18.725","Text":"Organic molecules that must come from food,"},{"Start":"01:18.725 ","End":"01:23.315","Text":"of course, are carbohydrates, proteins and fats."},{"Start":"01:23.315 ","End":"01:28.430","Text":"Different foods contain different amounts of each of them."},{"Start":"01:28.430 ","End":"01:33.680","Text":"Let\u0027s say bread or potatoes contain a large amount of carbohydrates."},{"Start":"01:33.680 ","End":"01:35.510","Text":"It\u0027s not that they don\u0027t contain any protein,"},{"Start":"01:35.510 ","End":"01:38.180","Text":"but they contain primarily those things."},{"Start":"01:38.180 ","End":"01:42.345","Text":"Milk, fish, meat contain large amounts of proteins."},{"Start":"01:42.345 ","End":"01:45.875","Text":"Again, there is overlap of some materials,"},{"Start":"01:45.875 ","End":"01:52.180","Text":"say there\u0027s beans that contain quite a few carbohydrates and proteins."},{"Start":"01:52.180 ","End":"01:58.290","Text":"There is the last group of organic molecules,"},{"Start":"01:58.290 ","End":"02:05.625","Text":"the fats and those are found in things like milk and in chocolate,"},{"Start":"02:05.625 ","End":"02:09.065","Text":"almonds and cheeses of course,"},{"Start":"02:09.065 ","End":"02:10.520","Text":"in eggs to some degree."},{"Start":"02:10.520 ","End":"02:13.940","Text":"Now there are essential nutrients that are"},{"Start":"02:13.940 ","End":"02:19.729","Text":"required materials that an animal cannot make itself."},{"Start":"02:19.729 ","End":"02:25.340","Text":"They must gather them from simpler organic molecules What are these required materials?"},{"Start":"02:25.340 ","End":"02:27.310","Text":"Of course they are the amino acids."},{"Start":"02:27.310 ","End":"02:30.124","Text":"There are 20 different amino acids that compose"},{"Start":"02:30.124 ","End":"02:34.705","Text":"the proteins and there are 8 of them that are absolutely essential."},{"Start":"02:34.705 ","End":"02:40.020","Text":"They are essential fatty acids and of course they are the vitamins and minerals."},{"Start":"02:40.020 ","End":"02:42.275","Text":"Where do the amino acids come from?"},{"Start":"02:42.275 ","End":"02:48.535","Text":"Amino acids come primarily from plants and from meat,"},{"Start":"02:48.535 ","End":"02:54.140","Text":"but you\u0027ll notice that some plants like this corn have large amounts of say,"},{"Start":"02:54.140 ","End":"02:55.810","Text":"tryptophan and methionine,"},{"Start":"02:55.810 ","End":"02:59.370","Text":"but they don\u0027t contain lots of valine,"},{"Start":"02:59.370 ","End":"03:01.950","Text":"threonine, phenylalanine, and so on."},{"Start":"03:01.950 ","End":"03:04.785","Text":"Isoleucine, lysine, they don\u0027t contain hardly at all."},{"Start":"03:04.785 ","End":"03:07.320","Text":"These are all various amino acids, yes."},{"Start":"03:07.320 ","End":"03:12.545","Text":"In order for a vegetarian to get what he needs,"},{"Start":"03:12.545 ","End":"03:17.210","Text":"then he or she is going to have to eat a combination"},{"Start":"03:17.210 ","End":"03:21.755","Text":"of different plants to make up all 20 amino acids."},{"Start":"03:21.755 ","End":"03:24.470","Text":"If people are not vegetarians,"},{"Start":"03:24.470 ","End":"03:27.275","Text":"they can get all 20 from meat,"},{"Start":"03:27.275 ","End":"03:30.345","Text":"milk, eggs and so on."},{"Start":"03:30.345 ","End":"03:33.170","Text":"As we said, vegetarians should combine plant products"},{"Start":"03:33.170 ","End":"03:35.840","Text":"to provide all the essential amino acids."},{"Start":"03:35.840 ","End":"03:37.445","Text":"In addition to that,"},{"Start":"03:37.445 ","End":"03:39.700","Text":"there are the essential fatty acids."},{"Start":"03:39.700 ","End":"03:46.270","Text":"They must be obtained as well from the diets and include certain unsaturated fatty acids."},{"Start":"03:46.270 ","End":"03:51.020","Text":"In humans, those are called Omega-3 and Omega-6 that you can"},{"Start":"03:51.020 ","End":"03:56.164","Text":"see are found in different oils in different amounts."},{"Start":"03:56.164 ","End":"03:59.720","Text":"Some animals can synthesize many of these fatty acids,"},{"Start":"03:59.720 ","End":"04:03.140","Text":"but humans can\u0027t make a lot of them."},{"Start":"04:03.140 ","End":"04:08.750","Text":"Animals typically contain ample amounts of the essential fatty acids in their diet,"},{"Start":"04:08.750 ","End":"04:11.210","Text":"humans have to watch out."},{"Start":"04:11.210 ","End":"04:13.850","Text":"Lastly, there are vitamins."},{"Start":"04:13.850 ","End":"04:16.575","Text":"Vitamins are co-factors."},{"Start":"04:16.575 ","End":"04:20.930","Text":"They are organic compounds that humans can\u0027t synthesize for"},{"Start":"04:20.930 ","End":"04:25.810","Text":"the most part and they\u0027re required in small amounts because they\u0027re co-factors."},{"Start":"04:25.810 ","End":"04:27.870","Text":"Some of them are fat soluble,"},{"Start":"04:27.870 ","End":"04:32.435","Text":"some of them are water soluble and they\u0027re given letters as we know,"},{"Start":"04:32.435 ","End":"04:34.885","Text":"vitamin E, vitamin D and so on."},{"Start":"04:34.885 ","End":"04:40.970","Text":"Cellular metabolism, the different reactions that occur inside cells,"},{"Start":"04:40.970 ","End":"04:46.440","Text":"usually require some of these vitamins for various purposes."},{"Start":"04:46.440 ","End":"04:51.665","Text":"One of them is to soak up free radicals."},{"Start":"04:51.665 ","End":"04:55.700","Text":"Free radicals are molecules that carry an extra electron and are"},{"Start":"04:55.700 ","End":"05:01.460","Text":"therefore very reactive and they can cause damage inside cells."},{"Start":"05:01.460 ","End":"05:09.185","Text":"Some of these vitamins can soak up some of these free radicals to defend the body."},{"Start":"05:09.185 ","End":"05:12.380","Text":"Examples of them would be vitamin C, E,"},{"Start":"05:12.380 ","End":"05:17.725","Text":"and A. Lastly, we\u0027ll discuss minerals."},{"Start":"05:17.725 ","End":"05:20.270","Text":"There is calcium, chlorine,"},{"Start":"05:20.270 ","End":"05:22.320","Text":"copper, iron and so on,"},{"Start":"05:22.320 ","End":"05:24.195","Text":"various minerals in the cell."},{"Start":"05:24.195 ","End":"05:28.205","Text":"They are simple inorganic nutrients, they\u0027re not carbon."},{"Start":"05:28.205 ","End":"05:30.890","Text":"They\u0027re usually also required in small amounts,"},{"Start":"05:30.890 ","End":"05:34.955","Text":"because they too are co-factors that help in"},{"Start":"05:34.955 ","End":"05:40.130","Text":"various enzymes or they help various enzymes or various proteins work."},{"Start":"05:40.130 ","End":"05:46.230","Text":"Consumption of large amounts of some of these can throw off homeostasis."},{"Start":"05:46.230 ","End":"05:49.760","Text":"They too have to be eaten in the right amounts."},{"Start":"05:49.760 ","End":"05:56.045","Text":"Animals need food to obtain energy and maintain homeostasis."},{"Start":"05:56.045 ","End":"05:59.955","Text":"Where do they get it? They get it from glucose."},{"Start":"05:59.955 ","End":"06:04.055","Text":"They get primarily energy from sugars, like glucose."},{"Start":"06:04.055 ","End":"06:06.590","Text":"That\u0027s the primary source of energy for animals,"},{"Start":"06:06.590 ","End":"06:12.265","Text":"or other digestible carbohydrates that are then converted to glucose."},{"Start":"06:12.265 ","End":"06:18.065","Text":"The energy is then stored in ATP or adenosine triphosphate."},{"Start":"06:18.065 ","End":"06:20.555","Text":"That\u0027s the primary energy currency."},{"Start":"06:20.555 ","End":"06:23.645","Text":"The energy from the glucose is transferred to"},{"Start":"06:23.645 ","End":"06:28.315","Text":"ATP and then is used later when it\u0027s required."},{"Start":"06:28.315 ","End":"06:31.385","Text":"When the amount of ATP is higher than required,"},{"Start":"06:31.385 ","End":"06:35.090","Text":"then what happens is that glycogen is made."},{"Start":"06:35.090 ","End":"06:37.370","Text":"That\u0027s another carbohydrate."},{"Start":"06:37.370 ","End":"06:43.220","Text":"It\u0027s stored in the liver and some of it in the muscles to store some of this energy."},{"Start":"06:43.220 ","End":"06:46.040","Text":"Therefore when the blood sugar drops,"},{"Start":"06:46.040 ","End":"06:52.600","Text":"the liver then can release some of the energy which is stored in the glycogen."},{"Start":"06:52.600 ","End":"06:54.884","Text":"Yes, in the form of glucagon."},{"Start":"06:54.884 ","End":"07:00.380","Text":"Then it makes glucose again and the glucose then goes back into"},{"Start":"07:00.380 ","End":"07:07.350","Text":"the bloodstream and the energy can then be used by cells."}],"ID":27327}],"Thumbnail":null,"ID":255410},{"Name":"Digestive System Processes","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Human Digestive System from Ingestion to Elimination","Duration":"9m 45s","ChapterTopicVideoID":26421,"CourseChapterTopicPlaylistID":255411,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.870","Text":"Hi. Welcome back and we\u0027ll delve more deeply in"},{"Start":"00:03.870 ","End":"00:07.650","Text":"this video into the digestive system of humans."},{"Start":"00:07.650 ","End":"00:11.580","Text":"Of course, obtaining nutrition and energy from food is"},{"Start":"00:11.580 ","End":"00:16.560","Text":"a multi-step process that we really call digestion."},{"Start":"00:16.560 ","End":"00:22.590","Text":"In this process, we have several things that must happen."},{"Start":"00:22.590 ","End":"00:24.300","Text":"Of course, first of all,"},{"Start":"00:24.300 ","End":"00:26.610","Text":"we have to have ingestion."},{"Start":"00:26.610 ","End":"00:31.380","Text":"That is, the food has to go in to our bodies."},{"Start":"00:31.380 ","End":"00:37.185","Text":"Secondly, it needs to be digested somehow through the body."},{"Start":"00:37.185 ","End":"00:42.675","Text":"Thirdly, it needs to be absorbed into the bloodstream."},{"Start":"00:42.675 ","End":"00:49.810","Text":"Fourthly, whatever doesn\u0027t get absorbed has to be eliminated through the bottom."},{"Start":"00:49.810 ","End":"00:53.300","Text":"Now let\u0027s look at each of these steps in a bit more detail."},{"Start":"00:53.300 ","End":"00:55.340","Text":"Let\u0027s start with ingestion."},{"Start":"00:55.340 ","End":"00:57.410","Text":"Ingestion, as we said,"},{"Start":"00:57.410 ","End":"00:59.540","Text":"we eat through the mouth."},{"Start":"00:59.540 ","End":"01:01.965","Text":"Yes, we eat through the mouth."},{"Start":"01:01.965 ","End":"01:06.575","Text":"In vertebrates and particularly in people, the teeth,"},{"Start":"01:06.575 ","End":"01:08.930","Text":"chew up the food,"},{"Start":"01:08.930 ","End":"01:14.315","Text":"breaking it into smaller pieces in a process called mastication."},{"Start":"01:14.315 ","End":"01:21.710","Text":"The saliva provides the liquids and some of the beginning enzymes and the tongue,"},{"Start":"01:21.710 ","End":"01:29.540","Text":"of course, to move things around in order to begin the process of chemical processing."},{"Start":"01:29.540 ","End":"01:32.270","Text":"Yes, those are the enzymes that are in the saliva and"},{"Start":"01:32.270 ","End":"01:36.145","Text":"the mechanical part is primarily done by the teeth."},{"Start":"01:36.145 ","End":"01:39.965","Text":"This prepares the food for swallowing so that it can then"},{"Start":"01:39.965 ","End":"01:44.905","Text":"go through the esophagus and into the stomach."},{"Start":"01:44.905 ","End":"01:49.955","Text":"The next process is the digestion itself,"},{"Start":"01:49.955 ","End":"01:55.670","Text":"which we said begins in the mouth but continues in the stomach,"},{"Start":"01:55.670 ","End":"01:58.390","Text":"comes through the esophagus."},{"Start":"01:58.390 ","End":"02:01.955","Text":"What happens there is mechanical"},{"Start":"02:01.955 ","End":"02:05.120","Text":"because the stomach also has muscles in it and so it moves"},{"Start":"02:05.120 ","End":"02:11.360","Text":"things around and further chemical breakdown into small absorbable fragments,"},{"Start":"02:11.360 ","End":"02:17.870","Text":"molecules eventually that are going to go primarily through the wall of the intestine."},{"Start":"02:17.870 ","End":"02:24.760","Text":"Here we have to increase the surface area of the food and chemically digested."},{"Start":"02:24.760 ","End":"02:26.990","Text":"Digested the large molecules into"},{"Start":"02:26.990 ","End":"02:29.660","Text":"smaller ones so that they can pass through the membranes."},{"Start":"02:29.660 ","End":"02:33.830","Text":"The small molecules later in other parts of the body are going"},{"Start":"02:33.830 ","End":"02:38.135","Text":"to be used to build the larger molecules."},{"Start":"02:38.135 ","End":"02:46.040","Text":"Now let\u0027s look at the particular different forms of large molecules that are digested."},{"Start":"02:46.040 ","End":"02:47.300","Text":"The first, of course,"},{"Start":"02:47.300 ","End":"02:50.120","Text":"are carbohydrates and digestion of"},{"Start":"02:50.120 ","End":"02:54.320","Text":"the carbohydrates begins in the mouth with the amylase."},{"Start":"02:54.320 ","End":"02:58.790","Text":"Yes, that\u0027s the enzyme which is found in saliva breaks down polysaccharides"},{"Start":"02:58.790 ","End":"03:03.560","Text":"into smaller polysaccharides further along in the small intestine."},{"Start":"03:03.560 ","End":"03:06.380","Text":"Enzymes from the pancreas, yes,"},{"Start":"03:06.380 ","End":"03:11.330","Text":"from the pancreas break down the smaller polysaccharides"},{"Start":"03:11.330 ","End":"03:16.965","Text":"into disaccharides that it\u0027s having 2 basic sugars."},{"Start":"03:16.965 ","End":"03:18.830","Text":"Then further in the small intestine,"},{"Start":"03:18.830 ","End":"03:20.030","Text":"the lining of the intestine,"},{"Start":"03:20.030 ","End":"03:25.675","Text":"there\u0027s a further breakdown of disaccharides into monosaccharides."},{"Start":"03:25.675 ","End":"03:29.720","Text":"Those monosaccharides are then transported across"},{"Start":"03:29.720 ","End":"03:35.540","Text":"the intestinal epithelium into the bloodstream so they get absorbed."},{"Start":"03:35.540 ","End":"03:38.810","Text":"The monosaccharides are what get absorbed."},{"Start":"03:38.810 ","End":"03:42.740","Text":"The larger sugars are broken down,"},{"Start":"03:42.740 ","End":"03:48.020","Text":"starting in the stomach and then in the small intestine."},{"Start":"03:48.020 ","End":"03:49.745","Text":"Looking at protein then,"},{"Start":"03:49.745 ","End":"03:54.620","Text":"remember a protein is made up of subunits called amino acids."},{"Start":"03:54.620 ","End":"03:57.815","Text":"What first happens is that in the stomach,"},{"Start":"03:57.815 ","End":"04:01.880","Text":"yes, we have a very low pH and pepsin,"},{"Start":"04:01.880 ","End":"04:05.420","Text":"which is the enzyme that is found primarily in the stomach,"},{"Start":"04:05.420 ","End":"04:09.770","Text":"breaks down protein into smaller pieces that are called peptides."},{"Start":"04:09.770 ","End":"04:11.450","Text":"In the small intestine,"},{"Start":"04:11.450 ","End":"04:14.705","Text":"then once it moves out of the stomach into the small intestine,"},{"Start":"04:14.705 ","End":"04:20.570","Text":"there are enzymes from the pancreas which break those peptides down into"},{"Start":"04:20.570 ","End":"04:28.939","Text":"smaller ones and further enzymes breakdown the peptides into amino acids,"},{"Start":"04:28.939 ","End":"04:37.760","Text":"and they then are absorbed into the bloodstream through the walls of the small intestine."},{"Start":"04:37.760 ","End":"04:40.945","Text":"Now let\u0027s look at lipids."},{"Start":"04:40.945 ","End":"04:44.455","Text":"Lipids are first digested in the stomach,"},{"Start":"04:44.455 ","End":"04:49.425","Text":"but mostly in the small intestine where pancreatic lipase,"},{"Start":"04:49.425 ","End":"04:52.344","Text":"lipase is the enzyme that does most of the work,"},{"Start":"04:52.344 ","End":"04:56.440","Text":"break down triglycerides into glycerol,"},{"Start":"04:56.440 ","End":"04:59.530","Text":"fatty acids, and monoglycerides."},{"Start":"04:59.530 ","End":"05:03.930","Text":"Now these things don\u0027t dissolve well in water."},{"Start":"05:03.930 ","End":"05:11.725","Text":"There is a process of getting those through the membranes and into the bloodstream,"},{"Start":"05:11.725 ","End":"05:16.330","Text":"first by emulsification, making an emulsion."},{"Start":"05:16.330 ","End":"05:20.755","Text":"The bile salts that have come from the liver help with that."},{"Start":"05:20.755 ","End":"05:26.630","Text":"Then those lipids are absorbed through the intestinal wall and then they\u0027re packed"},{"Start":"05:26.630 ","End":"05:33.145","Text":"inside the bloodstream into something that are called chylomicrons."},{"Start":"05:33.145 ","End":"05:39.469","Text":"These are large structures that are floating inside"},{"Start":"05:39.469 ","End":"05:45.399","Text":"the bloodstream and they have an interior that is hydrophobic,"},{"Start":"05:45.399 ","End":"05:50.360","Text":"therefore, the fatty acids can dissolve in them,"},{"Start":"05:50.360 ","End":"05:52.670","Text":"but a hydrophilic exterior,"},{"Start":"05:52.670 ","End":"05:55.990","Text":"they\u0027re a large emulsifiers."},{"Start":"05:55.990 ","End":"06:00.545","Text":"The chylomicrons enter the lymphatic vessels and then the blood"},{"Start":"06:00.545 ","End":"06:05.675","Text":"actually through a vein called the subclavian vein."},{"Start":"06:05.675 ","End":"06:08.975","Text":"Now, what about vitamins?"},{"Start":"06:08.975 ","End":"06:16.895","Text":"Vitamins are also some of them fat-soluble, others are water-soluble."},{"Start":"06:16.895 ","End":"06:18.935","Text":"Yes, as we\u0027ve discussed before,"},{"Start":"06:18.935 ","End":"06:21.650","Text":"the fat-soluble vitamins are absorbed"},{"Start":"06:21.650 ","End":"06:26.405","Text":"in the same manner as the lipids are that we just discussed."},{"Start":"06:26.405 ","End":"06:31.475","Text":"There some amount of dietary lipid is consumed"},{"Start":"06:31.475 ","End":"06:36.305","Text":"in the process of absorption of these lipid soluble vitamins,"},{"Start":"06:36.305 ","End":"06:41.380","Text":"the water-soluble ones are simply diffuse straight into the bloodstream."},{"Start":"06:41.380 ","End":"06:42.880","Text":"That\u0027s what we see here."},{"Start":"06:42.880 ","End":"06:45.910","Text":"We see the fat soluble proteins with the bile acids,"},{"Start":"06:45.910 ","End":"06:48.040","Text":"as we\u0027ve discussed earlier,"},{"Start":"06:48.040 ","End":"06:54.135","Text":"then the chylomicrons that go into the lymph and blood."},{"Start":"06:54.135 ","End":"06:57.940","Text":"Now let\u0027s look at the absorption in more detail."},{"Start":"06:57.940 ","End":"07:00.940","Text":"The absorption in the small intestine,"},{"Start":"07:00.940 ","End":"07:02.320","Text":"here\u0027s the small intestine,"},{"Start":"07:02.320 ","End":"07:07.630","Text":"there is absorption through the wall of the intestine into the capillaries"},{"Start":"07:07.630 ","End":"07:13.625","Text":"that are in the wall of the small intestine."},{"Start":"07:13.625 ","End":"07:19.460","Text":"The small intestine has a huge surface area because of all of these invaginations?"},{"Start":"07:19.460 ","End":"07:25.805","Text":"Yes and because of all the villi and microvilli that are on its surface."},{"Start":"07:25.805 ","End":"07:30.560","Text":"They are exposed to the intestinal lumen that is the inside"},{"Start":"07:30.560 ","End":"07:35.630","Text":"of the small intestine in something called a brush border."},{"Start":"07:35.630 ","End":"07:40.475","Text":"This greatly increases the rate of nutrient absorption."},{"Start":"07:40.475 ","End":"07:45.845","Text":"Then the transport across the epithelial cells can be either passive,"},{"Start":"07:45.845 ","End":"07:48.350","Text":"if it\u0027s just straight diffusion, or active."},{"Start":"07:48.350 ","End":"07:51.890","Text":"It depends on which nutrients we\u0027re talking about."},{"Start":"07:51.890 ","End":"07:54.125","Text":"Now, what about the large intestine?"},{"Start":"07:54.125 ","End":"07:56.765","Text":"In the large intestine, you\u0027ll remember primarily,"},{"Start":"07:56.765 ","End":"07:59.290","Text":"we get rid of water."},{"Start":"07:59.290 ","End":"08:02.765","Text":"The large intestine is composed of 3 different parts."},{"Start":"08:02.765 ","End":"08:05.780","Text":"First, the cecum, here\u0027s the small intestine,"},{"Start":"08:05.780 ","End":"08:09.530","Text":"the ileum, which goes into large intestine."},{"Start":"08:09.530 ","End":"08:12.304","Text":"First part is called the cecum."},{"Start":"08:12.304 ","End":"08:17.795","Text":"Then there is the colon in general that which is divided into an ascending,"},{"Start":"08:17.795 ","End":"08:20.120","Text":"transverse, and descending part."},{"Start":"08:20.120 ","End":"08:26.375","Text":"Finally, the rectum and the sigmoid colon at the end with the rectum,"},{"Start":"08:26.375 ","End":"08:30.520","Text":"which is attached to the anus where things come out the other end."},{"Start":"08:30.520 ","End":"08:35.600","Text":"The colon receives almost completely digested food from the cecum."},{"Start":"08:35.600 ","End":"08:37.850","Text":"Then water is absorbed back into"},{"Start":"08:37.850 ","End":"08:40.415","Text":"the bloodstream together with any nutrients that are left,"},{"Start":"08:40.415 ","End":"08:43.505","Text":"and then it passes waste to the rectum."},{"Start":"08:43.505 ","End":"08:46.145","Text":"The colon, as we just said,"},{"Start":"08:46.145 ","End":"08:50.570","Text":"is divided into 4 parts of the ascending, transverse, descending colon."},{"Start":"08:50.570 ","End":"08:55.445","Text":"Then there is the sigmoid colon at the very end of it."},{"Start":"08:55.445 ","End":"09:01.440","Text":"Finally, we have elimination right through the anus."},{"Start":"09:01.440 ","End":"09:04.130","Text":"There we remove the undigested food content and"},{"Start":"09:04.130 ","End":"09:06.815","Text":"waste products out of the digestive system."},{"Start":"09:06.815 ","End":"09:12.440","Text":"The undigested food material enters the colon where most of the water is reabsorbed,"},{"Start":"09:12.440 ","End":"09:18.590","Text":"as we\u0027ve said and the semisolid waste is moved from the colon and stored in the rectum."},{"Start":"09:18.590 ","End":"09:22.595","Text":"That\u0027s the area that\u0027s just before the anus."},{"Start":"09:22.595 ","End":"09:27.260","Text":"There, there are a series of these rectal valves that are very"},{"Start":"09:27.260 ","End":"09:33.380","Text":"sensitive and they control whether we poop or we don\u0027t."},{"Start":"09:33.380 ","End":"09:37.160","Text":"Yes. The rectum expansion triggers neural signals that"},{"Start":"09:37.160 ","End":"09:41.330","Text":"are felt that set up the urge to eliminate and finally,"},{"Start":"09:41.330 ","End":"09:46.020","Text":"the solid waste is eliminated through the anus."}],"ID":27328}],"Thumbnail":null,"ID":255411},{"Name":"Digestive System Regulation","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Digestive Regulation","Duration":"8m 22s","ChapterTopicVideoID":26422,"CourseChapterTopicPlaylistID":255412,"HasSubtitles":true,"ThumbnailPath":"https://www.proprep.uk/Images/Videos_Thumbnails/26422.jpeg","UploadDate":"2021-09-20T11:47:02.0700000","DurationForVideoObject":"PT8M22S","Description":null,"MetaTitle":"Digestive Regulation: Video + Workbook | Proprep","MetaDescription":"Animal Nutrition and the Digestive System - Digestive System Regulation. 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/animal-nutrition-and-the-digestive-system/digestive-system-regulation/vid27329","VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.635","Text":"Hi. We\u0027ve been discussing the digestive system,"},{"Start":"00:04.635 ","End":"00:07.470","Text":"and we\u0027ve looked at the various parts of it starting from"},{"Start":"00:07.470 ","End":"00:10.245","Text":"the mouth and ending in the anus."},{"Start":"00:10.245 ","End":"00:13.350","Text":"What we\u0027d like to do here in this video is to discuss"},{"Start":"00:13.350 ","End":"00:18.360","Text":"the regulation of the digestive system and see"},{"Start":"00:18.360 ","End":"00:26.445","Text":"what makes it start and stop and have some response to different foods that we eat."},{"Start":"00:26.445 ","End":"00:30.315","Text":"Now, it turns out that it\u0027s the brain,"},{"Start":"00:30.315 ","End":"00:36.880","Text":"which is the control center for the sensation of hunger and satiety of feeling full."},{"Start":"00:36.880 ","End":"00:38.315","Text":"But as we\u0027ll see,"},{"Start":"00:38.315 ","End":"00:42.920","Text":"there is actually a combination of both nervous activity to"},{"Start":"00:42.920 ","End":"00:48.170","Text":"the brain and hormones that do the work and the functions of the digestive system"},{"Start":"00:48.170 ","End":"00:51.560","Text":"then are regulated both through nerves to"},{"Start":"00:51.560 ","End":"00:55.865","Text":"the brain and the hormonal responses that are going to come from"},{"Start":"00:55.865 ","End":"01:01.910","Text":"the different tissues that are involved in digestion and so here you can"},{"Start":"01:01.910 ","End":"01:04.820","Text":"see different hormones that are made by"},{"Start":"01:04.820 ","End":"01:08.635","Text":"the different tissues that are related to digestion."},{"Start":"01:08.635 ","End":"01:11.750","Text":"Now let\u0027s look at neural responses to food,"},{"Start":"01:11.750 ","End":"01:14.045","Text":"that is the nervous responses."},{"Start":"01:14.045 ","End":"01:16.250","Text":"In the figure that\u0027s down below here,"},{"Start":"01:16.250 ","End":"01:21.470","Text":"you can see that when we see the food even or smell the food,"},{"Start":"01:21.470 ","End":"01:25.040","Text":"our brain tells the various organs to do different things."},{"Start":"01:25.040 ","End":"01:26.690","Text":"So one of the things, of course,"},{"Start":"01:26.690 ","End":"01:32.345","Text":"is the stomach releases gastrin which promotes production of stomach acids,"},{"Start":"01:32.345 ","End":"01:39.930","Text":"the intestine releases different substances, secretin and CCK,"},{"Start":"01:39.930 ","End":"01:42.720","Text":"which stands for cholecystokinin,"},{"Start":"01:42.720 ","End":"01:45.425","Text":"which we\u0027ll see later and this stimulate"},{"Start":"01:45.425 ","End":"01:49.625","Text":"different pancreatic juices and the bile from the liver."},{"Start":"01:49.625 ","End":"01:51.725","Text":"In any case, as you can see,"},{"Start":"01:51.725 ","End":"01:54.650","Text":"there is a neural response to the food,"},{"Start":"01:54.650 ","End":"01:59.210","Text":"and it simultaneously makes the stomach to"},{"Start":"01:59.210 ","End":"02:05.165","Text":"produce both hydrochloric acid and the appropriate enzymes."},{"Start":"02:05.165 ","End":"02:08.240","Text":"In addition to that, you\u0027ll recall that there are"},{"Start":"02:08.240 ","End":"02:11.390","Text":"peristaltic movements which move"},{"Start":"02:11.390 ","End":"02:15.215","Text":"things through the intestine and as we\u0027ll see in a few minutes,"},{"Start":"02:15.215 ","End":"02:20.420","Text":"those peristaltic movements are also affected by what we eat,"},{"Start":"02:20.420 ","End":"02:22.730","Text":"and they are under the control of the brain,"},{"Start":"02:22.730 ","End":"02:26.035","Text":"although not in a conscious way."},{"Start":"02:26.035 ","End":"02:29.015","Text":"First, we start when the stomach is full,"},{"Start":"02:29.015 ","End":"02:31.640","Text":"the brain detects that we are full,"},{"Start":"02:31.640 ","End":"02:36.065","Text":"that we have satiety and there is a signal for that as well,"},{"Start":"02:36.065 ","End":"02:40.175","Text":"which should make us want to stop eating so much."},{"Start":"02:40.175 ","End":"02:44.405","Text":"There are different phases of gastric control."},{"Start":"02:44.405 ","End":"02:48.590","Text":"There\u0027s what\u0027s called the cephalic phase, the gastric phase,"},{"Start":"02:48.590 ","End":"02:52.550","Text":"and the intestinal phase and each of these phases"},{"Start":"02:52.550 ","End":"02:58.330","Text":"requires many different enzymes and is under the neural control as well."},{"Start":"02:58.330 ","End":"03:00.855","Text":"As the neural control,"},{"Start":"03:00.855 ","End":"03:06.954","Text":"we see goes through various nerves to and back from the stomach,"},{"Start":"03:06.954 ","End":"03:13.250","Text":"and then there is the release of various hormones which make the pancreas,"},{"Start":"03:13.250 ","End":"03:19.145","Text":"for instance, and the liver excrete enzymes that digest the food."},{"Start":"03:19.145 ","End":"03:23.305","Text":"Let\u0027s start by looking at the cephalic phase."},{"Start":"03:23.305 ","End":"03:26.630","Text":"The food stimulation, that\u0027s the sight, smell,"},{"Start":"03:26.630 ","End":"03:34.370","Text":"and thought even of some of foods can stimulate our stomach to produce gastrin."},{"Start":"03:34.370 ","End":"03:37.670","Text":"Here\u0027s the gastrin over here and"},{"Start":"03:37.670 ","End":"03:42.965","Text":"those neurological signals originate in various parts of the brain,"},{"Start":"03:42.965 ","End":"03:46.730","Text":"and they reach the stomach through a particular nerve called"},{"Start":"03:46.730 ","End":"03:52.510","Text":"the vagus nerves or as a series of nerves that are together called the vagus nerves."},{"Start":"03:52.510 ","End":"03:57.575","Text":"They produce the production of the gastrin, as we said,"},{"Start":"03:57.575 ","End":"04:04.055","Text":"and also histamine, which is produced by endocrine cells."},{"Start":"04:04.055 ","End":"04:06.630","Text":"It\u0027s a conditioned reflex."},{"Start":"04:06.630 ","End":"04:08.090","Text":"This really only occurs,"},{"Start":"04:08.090 ","End":"04:09.620","Text":"we like the food that we smell."},{"Start":"04:09.620 ","End":"04:12.095","Text":"If we smell something that we really don\u0027t like,"},{"Start":"04:12.095 ","End":"04:14.030","Text":"our stomachs not going to be working."},{"Start":"04:14.030 ","End":"04:16.520","Text":"Sometimes you\u0027ll say that my stomach is"},{"Start":"04:16.520 ","End":"04:19.865","Text":"gurgling after I\u0027ve smelled some food that I want to eat."},{"Start":"04:19.865 ","End":"04:21.485","Text":"Well, that\u0027s real."},{"Start":"04:21.485 ","End":"04:28.015","Text":"That\u0027s happening because our brain is telling our stomach to get ready for food."},{"Start":"04:28.015 ","End":"04:31.520","Text":"Now, what happens once food gets into our stomachs?"},{"Start":"04:31.520 ","End":"04:36.185","Text":"First thing that happens is that there is this tension."},{"Start":"04:36.185 ","End":"04:40.710","Text":"That is, there is stretching of the stomach and"},{"Start":"04:40.710 ","End":"04:48.510","Text":"this stretching leads to the release of hydrochloric acid by these parietal cells and,"},{"Start":"04:48.510 ","End":"04:50.935","Text":"of course, that lowers the pH of the cells,"},{"Start":"04:50.935 ","End":"04:56.930","Text":"and the lower pH in and of itself actually can break the food apart,"},{"Start":"04:56.930 ","End":"05:02.500","Text":"begin to do the digestion in and of itself because it hydrolyzes proteins to peptides."},{"Start":"05:02.500 ","End":"05:10.670","Text":"So this stimulation occurs due to the acetylcholine to the histamine and the gastrin,"},{"Start":"05:10.670 ","End":"05:12.395","Text":"as we mentioned earlier."},{"Start":"05:12.395 ","End":"05:15.169","Text":"Now, when the pH gets really low,"},{"Start":"05:15.169 ","End":"05:16.755","Text":"that is below 2,"},{"Start":"05:16.755 ","End":"05:23.060","Text":"the stomach says that\u0027s enough and then there is a decrease in the production of"},{"Start":"05:23.060 ","End":"05:27.230","Text":"hydrochloric acid and things begin to slow"},{"Start":"05:27.230 ","End":"05:32.125","Text":"down at this point because we don\u0027t want to begin digesting the stomach itself."},{"Start":"05:32.125 ","End":"05:35.290","Text":"Now we can move into the intestinal phase."},{"Start":"05:35.290 ","End":"05:42.860","Text":"Remember, the material that leaves the stomach is called chyme and the duodenum,"},{"Start":"05:42.860 ","End":"05:46.370","Text":"which is the beginning of the intestine will"},{"Start":"05:46.370 ","End":"05:51.115","Text":"then get delivered material which is below pH"},{"Start":"05:51.115 ","End":"05:55.550","Text":"2 and there could be lipids in there as well that were not"},{"Start":"05:55.550 ","End":"06:01.225","Text":"digested in the stomach because the stomach digest primarily proteins."},{"Start":"06:01.225 ","End":"06:04.350","Text":"Now, this chyme that\u0027s in"},{"Start":"06:04.350 ","End":"06:10.620","Text":"the duodenum inhibits gastric secretions and there are 3 ways that it does that."},{"Start":"06:10.620 ","End":"06:13.700","Text":"There are chemoreceptors in the duodenum;"},{"Start":"06:13.700 ","End":"06:15.418","Text":"they are stimulated by the low pH,"},{"Start":"06:15.418 ","End":"06:19.325","Text":"and then you get nervous signal that goes back to the brain and says,"},{"Start":"06:19.325 ","End":"06:23.840","Text":"stop making the stomach produce so much."},{"Start":"06:23.840 ","End":"06:30.044","Text":"There are local reflexes that don\u0027t have to go to the brain that are also see low pH."},{"Start":"06:30.044 ","End":"06:34.250","Text":"Lipids can do the same thing and then that means then that"},{"Start":"06:34.250 ","End":"06:40.040","Text":"the secretin and the CKK that we discussed before that are produced in the duodenum,"},{"Start":"06:40.040 ","End":"06:44.165","Text":"it decrease gastric secretions in the stomach."},{"Start":"06:44.165 ","End":"06:48.995","Text":"Finally, there is stimulation of the juices of by"},{"Start":"06:48.995 ","End":"06:54.580","Text":"the endocrine system of the liver and the pancreas."},{"Start":"06:54.580 ","End":"06:59.660","Text":"We said before that gastrin is produced in the stomach,"},{"Start":"06:59.660 ","End":"07:02.180","Text":"then an hydrochloric acid is made and"},{"Start":"07:02.180 ","End":"07:04.640","Text":"that aids in protein digestion, as what we said before."},{"Start":"07:04.640 ","End":"07:09.360","Text":"But the CKK and secretin stimulation, what do they do?"},{"Start":"07:09.360 ","End":"07:13.520","Text":"They neutralize the acidic chyme in that\u0027s now in"},{"Start":"07:13.520 ","End":"07:17.900","Text":"the duodenum because there is carbonate,"},{"Start":"07:17.900 ","End":"07:23.345","Text":"which is basic alkaline bicarbonate solution,"},{"Start":"07:23.345 ","End":"07:26.460","Text":"which is delivered from the pancreas,"},{"Start":"07:26.460 ","End":"07:28.735","Text":"and there is the CKK,"},{"Start":"07:28.735 ","End":"07:33.830","Text":"which stimulates the pancreas to produce the pancreatic juices,"},{"Start":"07:33.830 ","End":"07:35.885","Text":"and also the gallbladder."},{"Start":"07:35.885 ","End":"07:40.310","Text":"Then remember the gallbladder collects bile from the liver and"},{"Start":"07:40.310 ","End":"07:45.160","Text":"that induces the gallbladder to release bile into the duodenum."},{"Start":"07:45.160 ","End":"07:51.875","Text":"These are endocrine systems really that are in the duodenum."},{"Start":"07:51.875 ","End":"07:58.635","Text":"This then allows foods that are high in lipids to begin to be digested,"},{"Start":"07:58.635 ","End":"08:04.670","Text":"and it slows down the stomach peristalsis so there will be time,"},{"Start":"08:04.670 ","End":"08:08.075","Text":"the beginning of the small intestine to begin"},{"Start":"08:08.075 ","End":"08:12.770","Text":"the digestion in this area called the duodenum and this"},{"Start":"08:12.770 ","End":"08:15.980","Text":"allows the fatty foods more time to be"},{"Start":"08:15.980 ","End":"08:23.130","Text":"digested and absorbed as they move down through the small intestine."}],"ID":27329}],"Thumbnail":null,"ID":255412},{"Name":"Exercises","TopicPlaylistFirstVideoID":0,"Duration":null,"Videos":[{"Watched":false,"Name":"Exercise 1","Duration":"1m 16s","ChapterTopicVideoID":26922,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.340","Text":"Which of the following is a pseudo-ruminant?"},{"Start":"00:07.400 ","End":"00:10.799","Text":"Is it a cow, pig, crow,"},{"Start":"00:10.799 ","End":"00:15.045","Text":"or horse? Let\u0027s see."},{"Start":"00:15.045 ","End":"00:18.510","Text":"We remember that the cows are ruminants,"},{"Start":"00:18.510 ","End":"00:22.095","Text":"so it\u0027s not going to be a pseudo-ruminant."},{"Start":"00:22.095 ","End":"00:24.525","Text":"Pig is not a ruminant at all."},{"Start":"00:24.525 ","End":"00:26.235","Text":"A crow, well,"},{"Start":"00:26.235 ","End":"00:28.070","Text":"a crow is certainly not it,"},{"Start":"00:28.070 ","End":"00:30.120","Text":"it\u0027s a bird, so it\u0027s certainly not a ruminant,"},{"Start":"00:30.120 ","End":"00:31.785","Text":"so it must be a horse."},{"Start":"00:31.785 ","End":"00:38.490","Text":"Remember this slide in which the horse is a pseudo-ruminant,"},{"Start":"00:38.490 ","End":"00:45.373","Text":"which means that it has a 3-chambered stomach, a cecum,"},{"Start":"00:45.373 ","End":"00:48.785","Text":"a large intestine containing many microorganisms,"},{"Start":"00:48.785 ","End":"00:52.625","Text":"and the site where the roughage is fermented and digested."},{"Start":"00:52.625 ","End":"00:57.650","Text":"It\u0027s a pseudo-ruminant because it doesn\u0027t have"},{"Start":"00:57.650 ","End":"01:05.885","Text":"these other parts of the rumin area that cows, for instance, have it."},{"Start":"01:05.885 ","End":"01:09.545","Text":"An examples of those pseudo-ruminants are camels,"},{"Start":"01:09.545 ","End":"01:12.605","Text":"horses, or donkeys."},{"Start":"01:12.605 ","End":"01:16.920","Text":"Of course, our answer then is horse."}],"ID":28004},{"Watched":false,"Name":"Exercise 2","Duration":"1m 16s","ChapterTopicVideoID":26923,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.185","Text":"Which of the following statements is untrue?"},{"Start":"00:04.185 ","End":"00:06.030","Text":"Untrue, not true."},{"Start":"00:06.030 ","End":"00:09.960","Text":"That roughage takes a long time to digest?"},{"Start":"00:09.960 ","End":"00:15.465","Text":"That birds eat large quantities at one time so they can fly long distances?"},{"Start":"00:15.465 ","End":"00:18.660","Text":"That cows do not have upper teeth?"},{"Start":"00:18.660 ","End":"00:21.300","Text":"Or that in pseudo-ruminants,"},{"Start":"00:21.300 ","End":"00:24.540","Text":"roughage is digested in the cecum?"},{"Start":"00:24.540 ","End":"00:28.245","Text":"Roughage does take a long time to digest."},{"Start":"00:28.245 ","End":"00:30.345","Text":"That\u0027s not the answer."},{"Start":"00:30.345 ","End":"00:33.130","Text":"Cows do not have upper teeth."},{"Start":"00:33.130 ","End":"00:35.645","Text":"Remember in cows,"},{"Start":"00:35.645 ","End":"00:39.365","Text":"yes the upper teeth are absent and they use lower teeth,"},{"Start":"00:39.365 ","End":"00:40.775","Text":"tongue, and lips."},{"Start":"00:40.775 ","End":"00:43.053","Text":"That is true."},{"Start":"00:43.053 ","End":"00:45.815","Text":"Then so C is the wrong answer."},{"Start":"00:45.815 ","End":"00:48.230","Text":"Finally, in pseudo-ruminants,"},{"Start":"00:48.230 ","End":"00:50.179","Text":"roughage digested and the cecum,"},{"Start":"00:50.179 ","End":"00:53.840","Text":"that is true as well."},{"Start":"00:53.840 ","End":"00:58.700","Text":"In the cecum, large intestine containing many microorganisms digest plant materials and"},{"Start":"00:58.700 ","End":"01:04.025","Text":"that is the site where roughage is fermented and digested. That is true."},{"Start":"01:04.025 ","End":"01:05.795","Text":"That\u0027s the wrong answer."},{"Start":"01:05.795 ","End":"01:09.140","Text":"It must mean that our answer is B."},{"Start":"01:09.140 ","End":"01:16.080","Text":"Birds eat large quantities at one time so they can fly long distances."}],"ID":28005},{"Watched":false,"Name":"Exercise 3","Duration":"59s","ChapterTopicVideoID":26924,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.880","Text":"The acidic nature of chyme is neutralized by what?"},{"Start":"00:05.880 ","End":"00:12.390","Text":"Remember, chyme is what\u0027s produced in the stomach and it\u0027s very acidic."},{"Start":"00:12.390 ","End":"00:14.550","Text":"What\u0027s it going to be neutralized?"},{"Start":"00:14.550 ","End":"00:16.920","Text":"Is it by potassium hydroxide,"},{"Start":"00:16.920 ","End":"00:21.000","Text":"sodium hydroxide, bicarbonates, or vinegar?"},{"Start":"00:21.000 ","End":"00:28.665","Text":"Let\u0027s recall this slide in which we have the accessory organs,"},{"Start":"00:28.665 ","End":"00:32.460","Text":"in particular the pancreas and liver,"},{"Start":"00:32.460 ","End":"00:36.300","Text":"that are going to go into the duodenum,"},{"Start":"00:36.300 ","End":"00:39.480","Text":"which is the exits of the stomach."},{"Start":"00:39.480 ","End":"00:41.070","Text":"That\u0027s where the chyme is."},{"Start":"00:41.070 ","End":"00:43.805","Text":"Let\u0027s look at the pancreas."},{"Start":"00:43.805 ","End":"00:50.445","Text":"The pancreas secretes digestive juices that contain high levels of bicarbonate."},{"Start":"00:50.445 ","End":"00:56.615","Text":"What does that do? It neutralizes the acidic chyme that comes out of the stomach."},{"Start":"00:56.615 ","End":"01:00.000","Text":"Bicarbonates are our answer."}],"ID":28006},{"Watched":false,"Name":"Exercise 4","Duration":"1m 11s","ChapterTopicVideoID":26911,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.900","Text":"What is the primary fuel for the body?"},{"Start":"00:05.180 ","End":"00:07.815","Text":"Is it carbohydrates?"},{"Start":"00:07.815 ","End":"00:11.955","Text":"is it lipids, proteins, or glycogen?"},{"Start":"00:11.955 ","End":"00:14.475","Text":"Well, if you remember,"},{"Start":"00:14.475 ","End":"00:16.680","Text":"animals need food, of course,"},{"Start":"00:16.680 ","End":"00:19.230","Text":"to obtain energy and maintain homeostasis,"},{"Start":"00:19.230 ","End":"00:24.315","Text":"and it is glucose which is the primary source of energy for animals."},{"Start":"00:24.315 ","End":"00:30.570","Text":"The answer to our question clearly is going to be glucose,"},{"Start":"00:30.570 ","End":"00:31.995","Text":"is the primary source."},{"Start":"00:31.995 ","End":"00:36.170","Text":"Remember that the glucose comes"},{"Start":"00:36.170 ","End":"00:40.820","Text":"directly from the blood vessels into the various organs we need,"},{"Start":"00:40.820 ","End":"00:42.610","Text":"or if there\u0027s not enough there,"},{"Start":"00:42.610 ","End":"00:45.725","Text":"then one of the major sources is in the liver where"},{"Start":"00:45.725 ","End":"00:49.699","Text":"glycogen that is stored can be made into glucose,"},{"Start":"00:49.699 ","End":"00:52.400","Text":"which then goes into the blood vessels."},{"Start":"00:52.400 ","End":"00:56.905","Text":"The answer to our question then will be carbohydrates."},{"Start":"00:56.905 ","End":"01:00.315","Text":"Of course, our answer therefore is carbohydrates,"},{"Start":"01:00.315 ","End":"01:04.715","Text":"since glucose is the primary carbohydrate,"},{"Start":"01:04.715 ","End":"01:11.190","Text":"all other carbohydrates are metabolized into glucose."}],"ID":28007},{"Watched":false,"Name":"Exercise 5","Duration":"47s","ChapterTopicVideoID":26912,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.240","Text":"Excess glucose is stored where and it\u0027s stored how?"},{"Start":"00:06.240 ","End":"00:08.685","Text":"Is it stored as fats,"},{"Start":"00:08.685 ","End":"00:16.000","Text":"as glucagon or glycogen or it\u0027s not stored at all in the body?"},{"Start":"00:16.040 ","End":"00:27.165","Text":"Let\u0027s recall that glycogen is the storage of energy in the liver."},{"Start":"00:27.165 ","End":"00:32.855","Text":"Yes, animals need to obtain energy and to store it if they need it and of course,"},{"Start":"00:32.855 ","End":"00:36.590","Text":"glucose is the primary source of energy for the animals."},{"Start":"00:36.590 ","End":"00:38.765","Text":"Where is it stored?"},{"Start":"00:38.765 ","End":"00:40.400","Text":"We see it\u0027s stored in the liver,"},{"Start":"00:40.400 ","End":"00:43.325","Text":"as I just said, as glycogen."},{"Start":"00:43.325 ","End":"00:47.580","Text":"So, our answer is going to be glycogen."}],"ID":28008},{"Watched":false,"Name":"Exercise 6","Duration":"52s","ChapterTopicVideoID":26913,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.670","Text":"The digestive juices from the liver are delivered to where?"},{"Start":"00:05.670 ","End":"00:08.190","Text":"To the stomach? To the liver?"},{"Start":"00:08.190 ","End":"00:10.065","Text":"Well, it\u0027s from the liver to the liver, that can\u0027t be."},{"Start":"00:10.065 ","End":"00:12.840","Text":"To the duodenum or the colon?"},{"Start":"00:12.840 ","End":"00:21.525","Text":"Let\u0027s recall this figure in which we have the liver delivering its juices where?"},{"Start":"00:21.525 ","End":"00:26.055","Text":"To the duodenum via the gallbladder."},{"Start":"00:26.055 ","End":"00:29.955","Text":"Yes. Our answer is going to be duodenum."},{"Start":"00:29.955 ","End":"00:35.510","Text":"Remember that the chemical digestion breaks down large molecules into"},{"Start":"00:35.510 ","End":"00:41.600","Text":"small ones so that it can pass through the membranes of the intestine."},{"Start":"00:41.600 ","End":"00:42.800","Text":"But in any case,"},{"Start":"00:42.800 ","End":"00:46.970","Text":"the place where this happens for the bile that"},{"Start":"00:46.970 ","End":"00:52.500","Text":"comes out of the liver is in the duodenum. That\u0027s our answer."}],"ID":28009},{"Watched":false,"Name":"Exercise 7","Duration":"1m 43s","ChapterTopicVideoID":26914,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.855","Text":"A scientist dissects a new species of animal."},{"Start":"00:03.855 ","End":"00:11.360","Text":"If the animal\u0027s digestive system has a single stomach with an extended small intestine,"},{"Start":"00:11.360 ","End":"00:16.020","Text":"we\u0027re talking about a single stomach and an extended small intestine."},{"Start":"00:16.020 ","End":"00:20.325","Text":"To which animal could the dissected specimen be closely related?"},{"Start":"00:20.325 ","End":"00:21.555","Text":"Would it be a lion,"},{"Start":"00:21.555 ","End":"00:24.240","Text":"a snowshoe hare, an earthworm, or an eagle."},{"Start":"00:24.240 ","End":"00:26.280","Text":"We need to remember what"},{"Start":"00:26.280 ","End":"00:32.415","Text":"the different digestive systems look like in these various organisms."},{"Start":"00:32.415 ","End":"00:35.615","Text":"Let\u0027s start out with an earthworm."},{"Start":"00:35.615 ","End":"00:39.840","Text":"Remember, an earthworm has this digestive system that goes through."},{"Start":"00:39.840 ","End":"00:42.345","Text":"It doesn\u0027t have much of a stomach,"},{"Start":"00:42.345 ","End":"00:45.790","Text":"so an earthworm is not going to be really the answer."},{"Start":"00:45.790 ","End":"00:50.555","Text":"The elementary canals remember always has 2 openings right on either end,"},{"Start":"00:50.555 ","End":"00:53.504","Text":"but it doesn\u0027t have much of a stomach."},{"Start":"00:53.504 ","End":"00:54.830","Text":"The earthworm\u0027s not going to be the answer."},{"Start":"00:54.830 ","End":"00:55.955","Text":"What about the bird?"},{"Start":"00:55.955 ","End":"00:58.820","Text":"Remember that was one of the possibilities, the eagle."},{"Start":"00:58.820 ","End":"01:04.520","Text":"Well, it has several different structures over here,"},{"Start":"01:04.520 ","End":"01:09.760","Text":"remember, and those are not just one stomach."},{"Start":"01:09.760 ","End":"01:12.920","Text":"It\u0027s not going to be the bird either."},{"Start":"01:12.920 ","End":"01:16.215","Text":"It\u0027s got these 2 different chambers,"},{"Start":"01:16.215 ","End":"01:18.645","Text":"so it\u0027s not going to be that."},{"Start":"01:18.645 ","End":"01:24.305","Text":"It could be either the lion or the snowshoe hare."},{"Start":"01:24.305 ","End":"01:26.090","Text":"But if you remember,"},{"Start":"01:26.090 ","End":"01:29.950","Text":"it has an extended small intestine,"},{"Start":"01:29.950 ","End":"01:34.235","Text":"it means that it\u0027s going to be digesting probably a lot"},{"Start":"01:34.235 ","End":"01:38.855","Text":"of roughage and a lot of vegetable material,"},{"Start":"01:38.855 ","End":"01:43.230","Text":"so it\u0027s more likely to be the snowshoe hare."}],"ID":28010},{"Watched":false,"Name":"Exercise 8","Duration":"1m 39s","ChapterTopicVideoID":26915,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.380","Text":"Which of the following statements is not true?"},{"Start":"00:04.380 ","End":"00:07.920","Text":"Essential nutrients can be synthesized by the body."},{"Start":"00:07.920 ","End":"00:11.020","Text":"Is that true or not true?"},{"Start":"00:11.600 ","End":"00:14.535","Text":"Well, let\u0027s see. Remember that,"},{"Start":"00:14.535 ","End":"00:18.750","Text":"required materials that an animal cannot gather"},{"Start":"00:18.750 ","End":"00:23.400","Text":"from simple organic materials are called essential nutrients."},{"Start":"00:23.400 ","End":"00:28.905","Text":"Essential nutrients are required materials that it cannot gather."},{"Start":"00:28.905 ","End":"00:31.890","Text":"It said here that they can be synthesized."},{"Start":"00:31.890 ","End":"00:33.930","Text":"Is that not true?"},{"Start":"00:33.930 ","End":"00:37.210","Text":"Well, it\u0027s not true."},{"Start":"00:37.210 ","End":"00:41.240","Text":"Therefore, that will probably be our answer."},{"Start":"00:41.240 ","End":"00:42.620","Text":"Let\u0027s look at the other ones."},{"Start":"00:42.620 ","End":"00:46.175","Text":"Vitamins are required in small quantities for bodily function."},{"Start":"00:46.175 ","End":"00:48.560","Text":"Remember about vitamins,"},{"Start":"00:48.560 ","End":"00:51.485","Text":"they are required in a very small amount."},{"Start":"00:51.485 ","End":"00:54.665","Text":"That is true, so that will not be our answer."},{"Start":"00:54.665 ","End":"00:57.680","Text":"What about some amino acids can be synthesized by"},{"Start":"00:57.680 ","End":"01:00.530","Text":"the body while others need to be obtained from the diet?"},{"Start":"01:00.530 ","End":"01:07.595","Text":"Well, if remember, the essential amino acids must be provided from outside,"},{"Start":"01:07.595 ","End":"01:10.320","Text":"the foods must provide them all."},{"Start":"01:10.320 ","End":"01:13.580","Text":"They are not made by"},{"Start":"01:13.580 ","End":"01:17.570","Text":"the body and must be obtained for the diets so that\u0027s not the answer."},{"Start":"01:17.570 ","End":"01:20.120","Text":"What about vitamins coming together categories,"},{"Start":"01:20.120 ","End":"01:21.905","Text":"fat-soluble, and water-soluble?"},{"Start":"01:21.905 ","End":"01:23.165","Text":"Well, that is true."},{"Start":"01:23.165 ","End":"01:26.375","Text":"They do come in both fat and water-soluble."},{"Start":"01:26.375 ","End":"01:28.025","Text":"That\u0027s not our answer either."},{"Start":"01:28.025 ","End":"01:35.350","Text":"Therefore, our answer must be that essential nutrients can be synthesized by the body,"},{"Start":"01:35.350 ","End":"01:39.430","Text":"and that is not true."}],"ID":28012},{"Watched":false,"Name":"Exercise 9","Duration":"36s","ChapterTopicVideoID":26916,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:04.335","Text":"Which of the following is a water-soluble vitamin,"},{"Start":"00:04.335 ","End":"00:05.655","Text":"A, E,"},{"Start":"00:05.655 ","End":"00:07.875","Text":"K, or C?"},{"Start":"00:07.875 ","End":"00:11.175","Text":"You want a water-soluble vitamin."},{"Start":"00:11.175 ","End":"00:16.020","Text":"Here we just need to remember which are soluble and which are not."},{"Start":"00:16.020 ","End":"00:18.870","Text":"If remember the various vitamins,"},{"Start":"00:18.870 ","End":"00:22.035","Text":"then some are soluble and some are not."},{"Start":"00:22.035 ","End":"00:26.310","Text":"The water-soluble ones are C and B,"},{"Start":"00:26.310 ","End":"00:29.070","Text":"so of the answers that we had there,"},{"Start":"00:29.070 ","End":"00:30.915","Text":"what are the possibilities?"},{"Start":"00:30.915 ","End":"00:36.990","Text":"C. Vitamin C will be our answer."}],"ID":28011},{"Watched":false,"Name":"Exercise 10","Duration":"1m 54s","ChapterTopicVideoID":26917,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:07.020","Text":"Where does the majority of protein digestion take place?"},{"Start":"00:07.020 ","End":"00:09.360","Text":"Is it in the stomach, the duodenum,"},{"Start":"00:09.360 ","End":"00:12.390","Text":"the mouth, or the jejunum?"},{"Start":"00:12.390 ","End":"00:17.460","Text":"Let\u0027s consider what the stomach does."},{"Start":"00:17.460 ","End":"00:21.195","Text":"If you\u0027ll remember, the stomach is a sack like"},{"Start":"00:21.195 ","End":"00:25.200","Text":"organ that contains gastric digestive juices."},{"Start":"00:25.200 ","End":"00:28.470","Text":"Gastric just means that it\u0027s inside the stomach."},{"Start":"00:28.470 ","End":"00:35.189","Text":"There\u0027s a low pH that facilitates actually breakdown of proteins primarily and pepsin,"},{"Start":"00:35.189 ","End":"00:40.654","Text":"which also interacts or it digests proteins."},{"Start":"00:40.654 ","End":"00:43.925","Text":"Stomach is probably going to be our answer."},{"Start":"00:43.925 ","End":"00:50.900","Text":"Producing a mixture of ingested food that is called chyme."},{"Start":"00:50.900 ","End":"00:53.245","Text":"Stomach it could be."},{"Start":"00:53.245 ","End":"00:57.680","Text":"Duodenum it\u0027s not really because the duodenum is"},{"Start":"00:57.680 ","End":"01:03.965","Text":"where the chyme leaves the stomach and goes into the small intestine,"},{"Start":"01:03.965 ","End":"01:05.810","Text":"and that area is called the duodenum."},{"Start":"01:05.810 ","End":"01:08.690","Text":"It\u0027s certainly not the mouth because it\u0027s past the mouth."},{"Start":"01:08.690 ","End":"01:10.625","Text":"Remember what the jejunum is?"},{"Start":"01:10.625 ","End":"01:12.565","Text":"Well, the jejunum,"},{"Start":"01:12.565 ","End":"01:14.625","Text":"here\u0027s the jejunum,"},{"Start":"01:14.625 ","End":"01:19.969","Text":"is actually the majority of the small intestine."},{"Start":"01:19.969 ","End":"01:28.715","Text":"The jejunum is the bulk where the bulk of chemical digestion takes place and absorption,"},{"Start":"01:28.715 ","End":"01:31.415","Text":"but primarily not of proteins."},{"Start":"01:31.415 ","End":"01:34.580","Text":"At least those absorption of amino acids there,"},{"Start":"01:34.580 ","End":"01:37.190","Text":"but not of the proteins themselves."},{"Start":"01:37.190 ","End":"01:40.325","Text":"Jejunum is not going to be our answer either."},{"Start":"01:40.325 ","End":"01:43.850","Text":"They are the other parts of the intestines that we\u0027re on"},{"Start":"01:43.850 ","End":"01:47.600","Text":"this slide and so it was not the jejunum either."},{"Start":"01:47.600 ","End":"01:54.570","Text":"The answer to where the majority of protein digestion takes place is the stomach."}],"ID":28013},{"Watched":false,"Name":"Exercise 11","Duration":"53s","ChapterTopicVideoID":26918,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.720","Text":"Lipases are enzymes that break down what?"},{"Start":"00:03.720 ","End":"00:08.115","Text":"Do they break down disaccharides or lipids?"},{"Start":"00:08.115 ","End":"00:10.245","Text":"That\u0027s probably going to be our answer."},{"Start":"00:10.245 ","End":"00:12.435","Text":"Lip, lipase, yes."},{"Start":"00:12.435 ","End":"00:15.120","Text":"Proteins or cellulose."},{"Start":"00:15.120 ","End":"00:19.800","Text":"Well, let\u0027s recall what the lipids do."},{"Start":"00:19.800 ","End":"00:24.524","Text":"The lipids, they begin in the stomach."},{"Start":"00:24.524 ","End":"00:26.460","Text":"The digestion begins in the stomach,"},{"Start":"00:26.460 ","End":"00:29.400","Text":"but mostly, it occurs in the small intestine."},{"Start":"00:29.400 ","End":"00:30.540","Text":"In the small intestine,"},{"Start":"00:30.540 ","End":"00:33.450","Text":"there is the pancreatic lipase."},{"Start":"00:33.450 ","End":"00:35.790","Text":"Well, that was our question, wasn\u0027t it?"},{"Start":"00:35.790 ","End":"00:39.830","Text":"Yes, where there is the breakdown of the triglycerides into glycerol,"},{"Start":"00:39.830 ","End":"00:41.965","Text":"fatty acids, and monoglycerides."},{"Start":"00:41.965 ","End":"00:45.845","Text":"Certainly, the answer to our question is going to be"},{"Start":"00:45.845 ","End":"00:53.730","Text":"lipase is in charge of breaking down lipids. That\u0027s our answer."}],"ID":28014},{"Watched":false,"Name":"Exercise 12","Duration":"53s","ChapterTopicVideoID":26919,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:05.955","Text":"Which hormone controls the release of bile from the gallbladder?"},{"Start":"00:05.955 ","End":"00:08.595","Text":"We\u0027re looking now for a hormone."},{"Start":"00:08.595 ","End":"00:11.775","Text":"Pepsin, is that a hormone? No, it\u0027s not."},{"Start":"00:11.775 ","End":"00:13.860","Text":"Amylase, that\u0027s not either."},{"Start":"00:13.860 ","End":"00:15.855","Text":"These 2 are enzymes."},{"Start":"00:15.855 ","End":"00:20.700","Text":"What about CCK or gastrin?"},{"Start":"00:20.700 ","End":"00:24.950","Text":"Well, let\u0027s remember what CCK is."},{"Start":"00:24.950 ","End":"00:30.315","Text":"If you remember, CCK is going to be"},{"Start":"00:30.315 ","End":"00:37.020","Text":"something that stimulates the pancreas to produce the requisite pancreatic juices."},{"Start":"00:37.020 ","End":"00:41.445","Text":"It acts in tandem with secretin."},{"Start":"00:41.445 ","End":"00:47.295","Text":"Remember CCK acts together with secretin, those are hormones."},{"Start":"00:47.295 ","End":"00:52.930","Text":"Therefore, CCK is going to be our answer."}],"ID":28015},{"Watched":false,"Name":"Exercise 13","Duration":"1m 24s","ChapterTopicVideoID":26920,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:06.320","Text":"Which hormone stops acid secretion in the stomach?"},{"Start":"00:08.750 ","End":"00:11.250","Text":"We\u0027re looking again for a hormone."},{"Start":"00:11.250 ","End":"00:13.615","Text":"Is it gastrin, somatostatin,"},{"Start":"00:13.615 ","End":"00:19.005","Text":"gastric inhibitory peptide, or CCK?"},{"Start":"00:19.005 ","End":"00:24.100","Text":"It\u0027s not going to be gastrin. That\u0027s for sure."},{"Start":"00:24.100 ","End":"00:31.000","Text":"Why? Because gastrin is something that increases the gastric juices,"},{"Start":"00:31.000 ","End":"00:35.555","Text":"it stimulates the gastric juices and that we were asked about inhibition."},{"Start":"00:35.555 ","End":"00:38.170","Text":"That\u0027s clearly not it."},{"Start":"00:38.170 ","End":"00:41.500","Text":"Yes, gastrin stimulates the release of"},{"Start":"00:41.500 ","End":"00:47.498","Text":"hydrochloric acid in the stomach and it does aid in digestion,"},{"Start":"00:47.498 ","End":"00:49.220","Text":"but that\u0027s not we were asked."},{"Start":"00:49.220 ","End":"00:56.430","Text":"We were asked which one stops acid secretion and this actually does quite the opposite."},{"Start":"00:56.620 ","End":"00:59.510","Text":"What might it be?"},{"Start":"00:59.510 ","End":"01:02.150","Text":"Is it gastric inhibitory peptide?"},{"Start":"01:02.150 ","End":"01:03.680","Text":"No, it\u0027s not."},{"Start":"01:03.680 ","End":"01:06.905","Text":"Let\u0027s leave somatostatin aside for the moment."},{"Start":"01:06.905 ","End":"01:16.550","Text":"If you remember, CCK or cholecystokinin is also stimulates the pancreas,"},{"Start":"01:16.550 ","End":"01:18.620","Text":"so that\u0027s not going to be the answer."},{"Start":"01:18.620 ","End":"01:23.670","Text":"Therefore, our answer must be somatostatin."}],"ID":28016},{"Watched":false,"Name":"Exercise 14","Duration":"1m 12s","ChapterTopicVideoID":26921,"CourseChapterTopicPlaylistID":261503,"HasSubtitles":true,"ThumbnailPath":null,"UploadDate":null,"DurationForVideoObject":null,"Description":null,"MetaTitle":null,"MetaDescription":null,"Canonical":null,"VideoComments":[],"Subtitles":[{"Start":"00:00.000 ","End":"00:03.060","Text":"In the famous conditioning experiment,"},{"Start":"00:03.060 ","End":"00:08.880","Text":"Pavlov demonstrated that his dogs started drooling in response to a bell sounding."},{"Start":"00:08.880 ","End":"00:13.380","Text":"What part of the digestive process that he stimulate?"},{"Start":"00:13.380 ","End":"00:17.730","Text":"Was it the cephalic phase, the gastric phase,"},{"Start":"00:17.730 ","End":"00:22.170","Text":"the intestinal phase, or the elimination phase?"},{"Start":"00:22.170 ","End":"00:27.495","Text":"Well, let\u0027s recall what the cephalic phase is."},{"Start":"00:27.495 ","End":"00:29.864","Text":"In the cephalic phase,"},{"Start":"00:29.864 ","End":"00:32.940","Text":"there is food stimulation, sight,"},{"Start":"00:32.940 ","End":"00:38.135","Text":"smell, thought, and tactile stimulations that stimulate the gastric secretion."},{"Start":"00:38.135 ","End":"00:39.350","Text":"Now think about Pavlov,"},{"Start":"00:39.350 ","End":"00:41.570","Text":"what did he do? He rang the bell."},{"Start":"00:41.570 ","End":"00:47.595","Text":"It made the dog think, yes about digestion."},{"Start":"00:47.595 ","End":"00:52.555","Text":"The answer must be the cephalic phase to our question."},{"Start":"00:52.555 ","End":"00:57.275","Text":"Those are neurological signals that originate in the cerebral cortex."},{"Start":"00:57.275 ","End":"01:03.290","Text":"Yes, that make our brain control what goes on in our stomach,"},{"Start":"01:03.290 ","End":"01:05.980","Text":"and this can be a conditioned reflex."},{"Start":"01:05.980 ","End":"01:10.320","Text":"The cephalic phase was the answer to our question."}],"ID":28017}],"Thumbnail":null,"ID":261503}]

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