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BIOL 3324 Human Physiology - BIOL3324_lecture21_1109
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00:05 We only need one out of the better to have two. All
00:09 y'all. Um today, what we're is we are gonna talk about the
00:13 system. And um as I um everything from the last lecture
00:18 I think is much easier to much more straightforward. And so hopefully
00:24 through this stuff won't be too Uh uh Again, I think this
00:28 is kind of fun. Um So off, what we're going to do
00:32 we are going to describe just very the tube that we're going to be
00:35 with. And so we have the tract and this is the tube.
00:40 right. And so what this it starts with the oral cavity.
00:42 you go mouth the pharynx, pharynx esophagus, esophagus, to stomach,
00:46 to the small intestine, which has areas, duodenum, Juju ilium.
00:50 then you go to the large intestine has uh four areas, three areas
00:54 which we're really concerned, which is cum the colum, the rectum and
00:57 appendix is there as well, but kind of dangles off to the
01:00 Hence the name appendix. All And then we have accessory glands or
01:07 structures that are associated with the digestive , which includes your salivary glands.
01:11 includes the pancreas and specifically the X portion of the pancreas. Um It
01:17 the biliary structures which are the liver the gallbladder. So, what we're
01:21 do over the next two days is gonna cover all of these structures and
01:25 they do. All right. And what we want to deal with is
01:28 want to ask the question of how we take something that we call food
01:32 turn it into something we call All right. So I've already tasked
01:37 person, but I'm gonna task the of you all. I want you
01:39 think about something that we can use our model meal for this class.
01:45 right. So I the, the meal needs to have all aspects of
01:50 you'd find in a meal. So the things that mom says, it
01:54 a nice roll around in meals. it needs to have carbohydrates, it
01:58 to have fats, it needs to proteins. Those are the three
02:02 right? And then of course, that is uh food is also going
02:06 have nucleic acids in it. So should we have for our meal?
02:11 had something like what? OK. gonna have a milkshake. That's not
02:15 only part of the milk because we're gluttons. So, what else
02:18 we have? Lasagna. All we're gonna lasagna. So, in
02:23 lasagna we're, is it gonna be meat lasagna or vegetarian lasagna? All
02:26 . Meat lasagna, proper lasagna. layers. Ok. She supposes.
02:33 right. So we got lasagna and milkshake. Is there anything else we
02:37 to? Uh huh. A Is that what I heard?
02:40 Ok. Well, we need to our salad on the side because,
02:43 know, we want to be regular . Ok. So in that,
02:47 we have all the components that we ? Do we have fats in our
02:51 ? Yes, we do. All . So the fats are in the
02:55 that are in that meal. It's the, uh, uh, the
02:59 and the cheese that we have in meal. So just remember and then
03:03 terms of proteins, we got meat there, we have cheese. All
03:06 . So those are gonna be And then do we have carbohydrates?
03:09 like, oh, yes, we . What type of milkshake is
03:13 Chocolate? All right. Is it a double chocolate? Extra thick?
03:17 right. We're going all the way whipped cream on the top.
03:22 Perfect. I am a happy man I haven't eaten since yesterday. I
03:28 have breakfast and I failed to have take. So I am gonna be
03:33 at the end of this one. hope you all ate. No.
03:37 . Ok. Well, good luck you all too. All right.
03:39 thing or the first thing about the system, it is outside your
03:44 All right. Now, when we about outside the body, we think
03:49 , right? But I, I I've mentioned this already is that this
03:52 surface that is hidden away. See I open up my mouth.
03:56 do you see surface? All that surface continues on down my
04:02 you down my pharynx, down my continues through these structures and finishes at
04:07 anus. In other words, it's big giant tube that goes through your
04:11 body. It's a tunnel, So it is a structure unlike the
04:17 of a donut, right? So are like a doughnut, you are
04:21 you eat. All right. So is a tube that passes through.
04:26 , how do we know apart from like, ok, well, it's
04:30 . What are some of the characteristics things that are outside versus inside?
04:34 that's what this little list here. off ph is way too low to
04:38 inside your body. If you had Ph of two inside your body,
04:42 the proteins that make up your body start dissociating and falling apart. So
04:47 we have is we have a Ph low in a very, very specific
04:53 that's outside the body. You also enzyme or Ph on the outside of
04:58 body that is there to kill all of horrible things. So your Ph
05:03 here is different than the ph, your body. What's ph, inside
05:07 body? It's roughly between 6.8 and . And so ph on the surface
05:11 the body is around five ph in stomach is around two. So outside
05:17 body, different ph second thing, in order to break things down,
05:24 have to have enzymes to do And if you had those digestive enzymes
05:29 your body, are you any different the food that you eat? In
05:33 words, are you anything other than , fats and carbohydrates and nucleic
05:40 No enzymes are specific to what they , but they're not specific to the
05:47 to which they can digest. So we put um you know, I
05:53 know, we'll just say put vegetables your stomach, it's gonna digest it
05:57 it doesn't recognize and go oh these plants and so it's OK.
06:03 If you put, let's say you're cannibal and we put human arm in
06:06 body in your stomach, would it the, the, the human
06:11 Yes. Remember we are made of . It doesn't go oh no,
06:15 , no. That's human. We touch that. It's just proteins,
06:20 and carbohydrates plus some nucleic acids. , digestive enzymes are non-specific. So
06:28 they were in your body, they digest you. We put them outside
06:33 body where they can do the Now, also on the surface of
06:36 body, you have nucleic or you nucleus that are there to destroy viruses
06:40 bacteria. You have lysozyme, all of fun stuff that are there to
06:45 . So, enzymes are there to things out here on the surface just
06:49 they are there in the center to that. All right, you've been
06:53 about this since you've been here in and probably a little bit while you're
06:55 high school, your gut is filled all sorts of fun little micro
07:00 Right. We've heard about the gut . Yay. Interesting and fun.
07:05 . You actually have more bacteria in on the surface of your body than
07:08 have your own personal cells. they control everything that I do.
07:14 . All right. So the point is that if you put a macro
07:19 organism inside your body, what would ? That's called pathology. That's where
07:26 get sick and your immune system Uh, uh, that doesn't belong
07:29 . Right. So, it would it, but we don't have an
07:33 system that goes and attacks microorganisms in gut anymore than we have an immune
07:38 that attacks microorganisms that are on the of your skin and that live in
07:41 eyebrows. I'm saying that just to you up because you do have micro
07:46 living in your eyebrows. All Lastly, uh, food, the
07:52 , the salad and the milkshake. right. If I put them inside
07:59 body, how would my body treat as foreign? And if it's foreign
08:06 , it immune system. All If I put a cheeseburger on the
08:11 of my skin, does my, the lasagna on the surface of my
08:14 does my immune system care. And same thing if I put the
08:20 in my belly, my immune system really care. Ok, it's there
08:26 be broken down. It is on surface. So what this is,
08:30 a structure external to the body, though it appears to be internal,
08:35 is the whole of a doughnut. just so that you understand this,
08:38 you take a doughnut and bite into doughnut but not bite into the
08:43 do you still have a hole through donut? Is it still on the
08:47 ? Yeah. The stuff that you in a donut is the, I'm
08:51 call it the meat of the but it's not the meat. It's
08:55 , the yummy goodness of the All right. That's the rest of
08:58 body. When you think internally, the portion that we're thinking of.
09:03 outside that tube. All right. , things about the digestive system,
09:08 gonna regulate it through the endocrine There's gonna be Perrine action, there's
09:11 be neural mechanisms that are responsible for the activities that we're gonna be talking
09:15 . It is protected by the immune , but it's a barrier between the
09:20 and the re the rest of your . So, what we have here
09:23 what is called the gut associated lymphatic . The gault, there's also a
09:27 , there's, there's all sorts of ones, but the gault is that
09:31 between the gut and the rest of body. And so it is a
09:35 line of defense to make sure that you're not living by or if you're
09:39 by the five second rule or less even if you pick up something that's
09:42 and nasty, it's probably not gonna you. All right, we have
09:47 compartments and this is far more extensive we'll ever need to know. The
09:52 you can think about this is I'm asking you what are the different
09:55 I'm almost certain. I never asked question. There's like two sphincters or
09:59 sphincters out of the group that you know the pyloric sphincter, which is
10:02 to separate the stomach from the small . So it serves as the dividing
10:05 between the upper digestive tract and the digestive tract. Um But all of
10:11 little, these sphincters are basically good to tell you something new has happened
10:17 something new will be happening. All . So we have an upper esophageal
10:21 that separates the pharynx from the That means something is happening from here
10:26 that's different from downward. Something is between the esophagus and the stomach.
10:31 right. So use these sphincters as way to recognize change is occurring.
10:38 right. Now, the, the sphincters that I want you to be
10:41 familiar with are these two down here we'll get to them a little bit
10:45 , but I should mention them And these are the last two sphincters
10:48 the body. They're very similar to we saw in the uh uh
10:52 We have an internal sphincter, we an external sphincter. These are both
10:56 uh refer to the anus itself. so the internal one is smooth,
11:01 external one is skeletal. So we control one, we don't.
11:04 if you ever had that uh urge have a bowel movement that is pressure
11:11 uh the lower uh really the And so what you're doing is
11:16 you're moving uh feces into that en and the smooth muscle has relaxed.
11:22 if you're like, I can't go now, that's you controlling the external
11:27 sphincter. So both of them have be open in order for you to
11:33 . All right, that's the So I'm gonna time out here for
11:40 second. You don't need to write down. This is me making
11:43 One year, about eight years I was giving this lecture and my
11:47 died or I forgot my cord and whatever. All right. So I
11:51 to give an entire chalk talk choc if you don't know is when I
11:54 to go up there and just basically the pictures and explain what's going
11:58 If I can give a chalk talk the digestive system, you can give
12:02 a chalk talk on the digestive meaning that this is actually not as
12:07 as it may appear in cases. idea here is we're gonna see that
12:12 of these things can be put in . And in fact, one of
12:14 easiest charts to do is to say my structures, here's the different things
12:20 the top of the different types of activities that the uh digestive system can
12:25 and just kind of explain as you're along. What does it do
12:28 What does it do here? What it do here? This is one
12:30 those types of charts right here where like, OK, we have four
12:33 of the digestive system. Should I what these four layers are and what
12:36 do? Yeah, but it's not incredibly complex. And so these are
12:40 four layers, we have a we're gonna be working inside outward.
12:45 have the mucosa, the submucosa, muscularis and the CSA are these words
12:50 we've already seen in another system, of, we saw them in the
12:54 system, right? When we talked the, the bladder, we were
12:58 , well here, let's just talk this. All right. So these
13:01 are very, very similar to what saw when we talked about the
13:04 So tubes have all of these different . In the case of the digestive
13:09 , the mucosa exists in three the mucous membrane, which is what
13:14 seeing out here. That's the outermost . And within that mucus membrane,
13:18 gonna see a bunch of different things are kind of important. You might
13:21 exec glands, exec means to secrete , right? So if I'm secreting
13:28 and my digestive system is outside the , which way am I secreting into
13:34 digestive tract? Ok. So I that language kind of flipped things around
13:39 . But I want you to think terms of uh you can go ahead
13:43 cough as loud as you want. not interrupting me. It's terrible when
13:47 have something in your throat and you get rid of it. All
13:50 So, don't, don't feel embarrassed happens all the time. All
13:56 But the idea here is that when talking about exocrine, I'm secreting materials
14:00 the digestive tract to aid in the of digestion, that broader thing.
14:05 right. But we also have endocrine . Which way am I secreting when
14:09 doing endocrine into the body? what I'm gonna be doing is I'm
14:14 to secrete things into the bloodstream to signals to different parts of the digestive
14:19 . All right. And the last I have listed up here is I
14:22 specialized epithelial cells that are gonna play important role in absorbing materials because remember
14:27 is the purpose of the digestive system to turn that lasagna, that
14:32 that milkshake into absorbable sub units that can then use to either build my
14:39 or what I can use for energy my body. All right. So
14:44 , that's the goal here. Second that's unique about the mucosa. It's
14:48 be folded and it's gonna be folded some, some very unique ways depending
14:53 where I am and what I'm looking and in doing so what I'm I'm
14:58 is I'm probably gonna be increasing surface most of the cases, but I'm
15:03 aiding in the specific activities that are in that area. And so what
15:07 see, for example, is there folds in the mouth. In
15:11 you can feel them right now, your tongue over the roof of your
15:14 . Do you feel the bumps and like that? Yeah, those are
15:19 , right? And they're there for purpose and they don't really increase surface
15:23 for absorption or anything, but instead create these bumps and stuff so that
15:27 can grip your food and manipulate it the inside of your mouth. How
15:32 ever had a peanut butter sandwich? . Get that piece of white bread
15:39 you know, we're not mature. what we do is we go and
15:43 that big old slab of peanut you know, and, and then
15:49 do we do? We fold that boy over, put it in our
15:51 and then what is it stuck to top of your mouth? And what
15:57 you do? You can move it because it's not a smooth flat
16:03 It's bumpy. That's an example of . And that's just the example of
16:07 mouth. The esophagus folds differently than mouth, the stomach folds differently than
16:11 esophagus in the mouth. The small folds differently. The uh the large
16:16 folds differently. All of these have types of folds for different sorts of
16:22 . And we can manipulate the folds some cases, not necessarily in the
16:26 , but in other places, we contract the muscle layers of the mucosa
16:32 help increase and decrease and change the of folding. The other three
16:40 we have the submucosa that is basically uh connective tissue. It provides elasticity
16:45 dispensable or dispensable. If you like , you also like submucosa. So
16:50 what you do is you go take sheep or a pig or a cow
16:53 whatever and then you just stuff it of chopped up meat and leftover stuff
16:57 you do that, smoke it up now you've got yourself a sausage.
17:01 right. That's what casing is for most part. All right. It's
17:05 , it's the intestines of the All right. It stretches just
17:12 All right. Now, here within submucosa, you're gonna have larger blood
17:15 , large vessels. You'll, we'll talk about the, the uh submucosal
17:20 in brief here because it's part of of the things that regulates outside that
17:25 see the muscular exterra. So here are, there's a muscularis mucosa,
17:30 a sub down here. This is exter and here what we'll see typically
17:36 two layers. All right. So have a circumferential layer. So it
17:41 around the tube like this and you'll a longitudinal layer, one causes the
17:45 to squish right? Or to, get shorter, the other one squeezes
17:51 tube. OK. And we use to help move materials through the digestive
17:58 . There will also be associated with a myenteric. So the my is
18:02 to the muscle myenteric plexus, which a role in telling it when it
18:07 be contracting and then on the that's your serosa. That's that also
18:12 of the casing part that we It keeps the thing from overstretching or
18:15 distending. It also helps to prevent friction. So, uh have you
18:21 noticed that when you eat a And I did see your hand
18:23 So I'll get to you just a . So have you ever noticed that
18:26 you eat a lot? You might noises, right? You might feel
18:30 moving inside you. Has that ever ? Maybe if you ate a
18:34 really spicy meal, you might feel , your small intestines move around a
18:41 . And so there is a lot rubbing going on. So you do
18:44 that cirrhosis to prevent that from Yes, ma'am. We'll get to
18:52 in just a second. That's a question. But it's gonna be dealing
18:55 a broader question of what is So I'll get to that and if
18:58 don't answer your question, uh you tell me the answer. OK.
19:01 , ma'am. Um You're asking a anatomy question, I'm gonna try to
19:11 the answer to. So, with to the structures of the abdomen,
19:17 have a choa that sits partially in of and in some cases uh completely
19:24 other organisms or organs, right? we have uh uh the term we
19:30 is post peritoneal structures, I think the word and those are sitting behind
19:36 cirrhosis. So like your kidneys are peritoneal, but that cirrhosis is
19:40 but it only covers the front half the organ. All right. And
19:44 is a continuous structure within the abdomen . All right. But that's an
19:50 question. And it's like without showing a picture and how weird it
19:53 we're just gonna stay away. Now, to kind of answer your
19:58 , four basic processes. So when looking at these structures and we're going
20:02 mouth to pharynx to esophagus, yada yada, the question you should be
20:06 is of these four different types of is this structure involved in this
20:13 Some are gonna only have one, will have all four. All
20:17 So the idea here is we have and that is simply the muscular contractions
20:21 allow me to mix the materials that in the digestive tract. All
20:26 Second thing is secretion. This is I'm adding specific things from my body
20:31 aid in the processes that are gonna occurring down here, which are the
20:35 processes. All right. So we're things into the lumen so that we
20:40 digest the material digestion is simply the of these complex materials into absorbable sub
20:48 . So what we're doing is we're , hey, that milkshake where it's
20:51 and flows nice and easy through that . It is not broken down enough
20:57 me to actually get it into my . So my digestive tract is responsible
21:02 taking these complex molecules and turning them less complex molecules. That's the
21:10 And finally, absorption is taking that broken down substance. The thing
21:14 has gone through the process of digestion move across the Luminal wall so that
21:19 now in the body and then can sent to either build something or serve
21:24 a point of energy for something. right, that's the idea.
21:29 the way that we're gonna do this do this uh across, we're gonna
21:32 it either to the blood or we're add it to the lymph and
21:35 it depends on the substance that you're at and what it's doing and we'll
21:38 to it there. So, Ta da. All right. I
21:44 said you're a donut. I'm gonna trying to insult you all day
21:47 You are a conveyor belt and you a cement mixer. All right.
21:52 belt. Can you picture conveyor I put something on this end and
21:56 it just travels along and goes to end. All right. So that's
22:00 kind of motility. This is what what we'd call propulsive movement. All
22:06 . So with propulsive movement, I just trying to send from one side
22:10 the other. The other type of that's taking place uh through this process
22:16 what we would call a mixing All right. And here this is
22:20 where we're gonna be using uh the two processes to do either of these
22:26 things. All right. So first , let's deal with the tone.
22:30 what this is? I have to look to see what I wanted to
22:32 first. I got too excited to to answer your question. I'm not
22:34 there yet. All right. So it comes to tone, your digestive
22:39 has within it already a certain degree tone just like your blood vessels.
22:43 we said your blood vessels sit in middle state, they're not completely
22:47 they're not completely contracted. And it's gonna be dependent upon how much sympathetic
22:51 we get to contract and relax. , it's kind of the same
22:55 The idea here is that the digestive isn't going to be in a completely
22:58 state. It's not going to be a constricted state. Instead it sits
23:01 in between so it can modify its depending upon your need. All
23:08 One of the reasons we wanna do is because they are like really,
23:10 bad pantyhose. If you overstretch they will stay stretched and never return
23:15 to their original shape. So that's we wanna always have a certain amount
23:20 muscle, uh tension in it. terms of the propulsive movement, what
23:24 looking at here is propulsion. So can see what have I done is
23:28 am uh going through a peristaltic type squeezing. So I'm basically, I'm
23:33 that circular muscle and I'm squeezing and what I'm gonna do is I'm gonna
23:37 that muscle along the length. So idea is I'm squeezing here, then
23:41 squeezing here and I'm just doing that in doing so I'm propelling materials in
23:46 of where I'm doing the squeezing. right. So that would be an
23:50 . Now, the rate at which happens and how you're doing it is
23:54 differ from region to region. We're look at swallowing here in a little
23:59 and we're gonna see swallowing is pretty . But in other areas it's a
24:03 bit more complex, like the smallest it's a lot more complex than what
24:06 trying to accomplish. Mixing. We're take advantage but we're gonna be uh
24:13 what we did here where this, gonna be using that circular um
24:18 right? But what we're gonna do we're gonna squeeze in different areas.
24:21 , I want you to think about many of you guys are squeeze your
24:24 in the middle. Yeah. Just want to know you better find
24:29 who does the same thing because it in all sorts of horrible battles.
24:34 kind of like the which way does toilet paper supposed to fall comes off
24:38 top or let it fall underneath? . You guys know that fight.
24:45 way do you hang your toilet paper the top? Ok. That's the
24:50 way. It's in the patent. be surprised. She's like, of
24:53 . No, you'd be surprised there people who is like, no,
24:56 , see if you do it over top, then if you have a
24:58 cat, what does the cat And or if you have a
25:02 they do the same thing. it's harder to do it anyway.
25:07 right, I'm still coming to your because I know I have, you're
25:10 , why do I have to have of these muscles? Right. So
25:14 I squeeze a tube of toothpaste from middle, I am doing mixing.
25:18 about aquafresh. Aquafresh has your, know, your four bands,
25:22 And if I squeeze in the middle time, I no longer have
25:25 I now just have a mixture of gel and a paste. Have you
25:29 that? I mean, we don't care, you know, but that's
25:33 happens because when I squeeze, I'm materials towards the cap, but there's
25:39 that's also being squeezed back away from cap and it can only do,
25:43 , move in that area where there space and that's what's happening here.
25:47 I squeeze on either side, I'm the materials to each other and it
25:51 a mixing. Now, this is in terms of food. Um Do
25:58 guys like um jawbreakers? Yeah. fireballs. Yeah. Have you ever
26:07 to chew an atomic fireball or a pop? That candy? It's not
26:10 it's not like a Tootsie roll uh , right? Or Tootsie pop where
26:13 like lick, lick chew. I , you try. Jawbreakers are like
26:19 at the density of the sun, ? And you put it in it
26:23 lick lick and uh I, I do that. You have to get
26:26 down to a certain point before you even start taking chips off it.
26:29 right. So you can like lick molecule of sugar off at a
26:33 And you can imagine if my digestive didn't allow mixing what would happen is
26:37 those enzymes, all those materials that using to break down material could only
26:42 on that outer surface much like you on that atomic fireball or jawbreaker.
26:48 what happens with mixing is, is adding the materials on the outside nearest
26:54 the secretion is taking place. But because the bolus of material is loose
26:59 stuff, I am churning it over needing it in to that. So
27:03 taking the outside and pushing it inward I'm bringing the inside and moving it
27:07 and I can expose it to more . And so it speeds up the
27:12 of digestion because I'm not just doing one little molecule layer at a
27:18 If that makes sense, you guys how to need stuff, right?
27:23 . I'm just making sure, I , I, I used the word
27:27 in a classroom once and they all at me like this was some foreign
27:31 that no one had ever heard So I have to pretend sometimes that
27:35 I'm not getting a response, you know what I'm saying? Yeah.
27:42 yet. We're not, we're not there yet. So keep it in
27:45 and you can ask now, have answered the question so far or am
27:48 still like, wait a second, about these longitudinal muscles? Because I
27:51 mentioned longitudinal muscles. All right. in other areas like in the small
27:57 , the longitudinal muscles allow me to the length of the tube and then
28:04 reposition the materials and then lengthen it again. So it's kind of like
28:08 a worm moves. Did you guys to dissect worms at any point in
28:12 academic career? Yes. No, . So sad. But they,
28:19 how, how earthworms move is they extend themselves kind of grip. And
28:24 , I'm using the word grip in very loose definition way. And then
28:28 bring themselves back into a uh a position and then they stretch out the
28:33 end again and they shrink and rinse your small test and works kind of
28:40 that, right? So, motility moving the materials through for either the
28:48 of propulsion or for the purposes of secretion. What we're doing is we
28:54 going to think about um this material we're putting into the digestive system.
29:00 what we're talking about is water, gonna add in some electrolytes, we're
29:04 add in enzymes. You're gonna see salts, all these different things
29:09 these are things that are borrowed from body to aid in the process of
29:13 . So I say borrowed from the , we're gonna take it from the
29:17 and, and again, it's not you're like bleeding into your digestive
29:20 It's materials are being moved across the walls, water and all this other
29:26 transferred to the Luminal cells and the cells then secrete that in to the
29:33 tract. Ok. Now, this a lot of energy. All
29:39 But you've probably heard the adage in to make money, I have to
29:43 money. And that's the same thing . I'm expending energy in order to
29:47 a lot of energy. All So that's the idea. And then
29:51 we're gonna do is we're gonna reabsorb things that we borrowed and we're gonna
29:55 it back into the body. When talk about the large intestine, you're
29:58 see what sort of water investment you in your digestive tract. All
30:04 Now, I've asked this question I'm just double checking. Are we
30:06 friends here? Can we get personal little bit? Yeah. Have you
30:10 had diarrhea? Yeah. OK. making sure I'm, it's, it's
30:15 a foreign concept. I know it's something we talk about around the table
30:18 dinner time, but diarrhea is simply inability to absorb the water that you've
30:25 from your body. And so part that really, really loose stool is
30:30 water that didn't go back and that's it just escapes out through um the
30:37 . All right, just as an . So that's something that you
30:42 you've experienced. So you probably know I'm talking about now. Digestion is
30:51 the process of hydrolysis and those words be foreign to you. It's
30:57 That's foreign, but hydrolysis. What we doing? We're taking water,
31:00 breaking water. We're taking a hydroxyl and a hydrogen. We're adding it
31:04 , at the site of a broken . Right? So you break the
31:07 . Now, I'm gonna add my , I'm gonna add my hydrogen.
31:10 hunky dory, that's my hydrolysis. right. The way that this happens
31:15 we're gonna be using some very specific to make this happen in some very
31:20 locations. So, what we're gonna is we're gonna take carbohydrates. Our
31:24 are in the form of polysaccharides also the form. So when we say
31:28 , don't think just the starches think also the glycogen that's in the,
31:34 the cells. So like in our , we have, are we gonna
31:38 Italian sausage or are we gonna go like hamburger, Italian sausage?
31:43 So it's still protein from an right? And you can imagine that
31:49 from which that protein was derived has in it glycogen. And so we
31:54 to break that stuff down, Is not just, oh,
31:58 there's starches and you know, the and stuff that we're eating,
32:01 it's everywhere. All right. So gonna take these complex polysaccharides and we're
32:07 to break them down first into disaccharide then secondly into monosaccharide. And so
32:13 is the process of carbohydrate digestion. gonna look at this in more detail
32:18 Tuesday. Is it Tuesday? Next ? With today's Thursday. OK.
32:24 . Simple. We're just going to them into amino acids. We're also
32:27 to digest them as polypeptides. So doesn't have to go down to the
32:34 sub units. We can, we digest some peptides up to uh pta
32:39 . We'll see this again on Finally, in terms of fats,
32:43 are primary fat that we consume is the form of triglycerides. We're going
32:47 take those triglycerides and we're going to them down into mono glycerides into free
32:51 acids and we're going to absorb So that is the goal of the
32:55 process is to turn these complex things less complex things. And I not
33:00 have appeared in the nucleic acids. am I doing with a strand of
33:03 ? What am I turning it into acids? All right. And those
33:07 being reabsorbed. All right. So absorption primarily occurs in the small
33:13 All right. And I'm putting that on there. So when you see
33:16 question like webs absorption taking place, have one choice. The answer has
33:19 to be small intestine. All Now, what we're doing is we're
33:24 all those little small sub uh absorbable units and we're absorbing those.
33:29 there's other things, we're gonna start water, we're gonna absorb vitamins,
33:33 gonna start absorbing electrolytes. Now, we get down to, to these
33:37 of components, that's where the large is playing a larger role.
33:42 But we do absorb in the small these substances. The enteric nervous system
33:54 now considered an independent structure with regards the nervous system. All right,
34:00 used to just be lumped in with autonomic nervous system. And now if
34:04 start looking at the literature, they're of keeping it as a separate
34:08 It's not just parasympathetic and sympathetic, parasympathetic, sympathetic and enteric. And
34:13 this is is the submucosal uh nerve , as well as the meter nerve
34:20 . So we're dealing with both sensory we're dealing with motor fibers that work
34:24 in a simple reflex arc to allow to digest food. And what's really
34:29 about this is it means that your has to ha doesn't need to know
34:33 or not you have food in the tract in order to digest,
34:38 In other words, your digestive system work all by its lonesome, which
34:42 kind of cool. All right. the sensory neurons are there to detect
34:48 changes like stretch or what's actually inside lu and what's the chemical makeup and
34:53 sort of mechanical stimulation that might be there? Those are the things that
34:57 detecting so that it can then signal tell the process of digestion to
35:01 And so what are we doing? , we're telling the ooth muscles to
35:05 , to create that motility. We're the epithelial cells to secrete their materials
35:09 to absorb materials and then we're also the endocrine cells to start creating other
35:15 so that we can regulate the whole , not in just one compartment,
35:18 in multiple places. We also might telling the blood vessels to dilate and
35:26 distribute the blood more towards the digestive . Instead of away from it.
35:32 can occur completely independent of the central system and its own reflex circuit.
35:41 that's kind of the big picture of things that we're going to talk about
35:43 what we're gonna do now is we're walk through these structures. We're gonna
35:46 , here's structure number one, number two. And we're gonna ask
35:49 question, what's it doing with regard motility? What's it doing with regard
35:53 secretion? What's it doing with regard absorption? What's it doing with regard
35:57 digestion? So, as we go , that's the easiest way to look
36:01 it. What is the mouth? does it do? What's the
36:05 What does it do that sort of ? All right. So here's your
36:09 . Mouth is where digestion begins? right. So we're talking about the
36:14 of digestion, breaking things down. , digestion isn't a stomach thing.
36:20 it starts here. The moment you food in your mouth is the moment
36:23 begin di digesting food. Now, are parts of the mouth. You
36:26 be aware of the palate is what the oral cavity from the nasal
36:30 It's very hard hard in the very soft in the back. That
36:34 part is there not only to create hard surface that separates the two
36:39 but it's a hard surface to which can manipulate materials, manipulate food in
36:45 mouth. All right. And I've the, the extreme example of the
36:49 butter sandwich. Do you like your butter? Crunchy or smooth,
36:54 Let's have a vote. Smooth, . Excellent. If all you have
37:00 the house is smooth and you like . Don't forget airline peanuts. Uvula
37:10 the dual dangly thing in the back your mouth. It's a 50 point
37:13 question on the MC A T. actually uh you got, see the
37:22 I get, the younger you guys . Do you, have you guys
37:25 heard of the Far side cartoon? there's huh one person. All
37:30 Gary Larson. It, it it was just a, it was
37:34 , a daily and that was actually of his cartoons. It was
37:37 what is the dangly thing in the of your mouth? It was like
37:39 T and it was like bonus What is the dangly thing in the
37:42 of your throat called purpose of the is not to just sit there and
37:47 back and make a throat look like throat. Its purpose is is when
37:51 swallow it, the UVULA pushes upward because it's attached to the soft palate
37:57 and it closes off the nasal cavity that the direction of food is downward
38:03 of upward. Have you ever laughed drinking milk? Yeah. Yeah.
38:10 had a friend who did that. the best part. If you can
38:13 someone to laugh while they're drinking a and having that soda come right out
38:16 nose and they get, not only it coming out of the nose but
38:19 burning. It's, that, that's best, best feeling ever. And
38:23 reason that happens is because when they're , you push down the uvula so
38:27 fluid can then get up in there then when you create that force it
38:31 up and out through the nose, , awful, awful, but hilarious
38:34 it happens with somebody else. All . So that's the purpose uvula is
38:38 to direct the flow of food down into the pharynx and then beyond into
38:44 esophagus. The pharynx is a fancy for your throat. All right.
38:49 your pharynx actually has three areas. has the nasopharynx, oropharynx and the
38:55 . All right. And so that's just throat. So high throat,
38:58 throat, low throat, all Um It's the passage from the mouth
39:05 the esophagus, the tongue. This uh voluntary skeletal muscles. Its job
39:10 to guide food while you're chewing and . So that's pretty obvious if
39:14 uh are chewing on food, you . No, you'll probably notice how
39:17 chew on one side and then after while I get bored, I'm tired
39:20 doing that. So what do I ? Flip the food over to the
39:23 side? So the tongue is sitting manipulating the food and changing its position
39:27 that you can chew it better. finally the teeth they are responsible for
39:31 process of mastication. Please do not this word with another one.
39:38 you Yeah, there we go. , I'm, I'm sorry, I'm
39:43 having a good day today. All . The job of mastication is
39:50 It is a physical breakdown of the that you are eating. You ever
39:58 any of these things? Do you live stupid lives? Like how many
40:03 wafers can I shove in my There. She is awesome.
40:10 Don't swallow. Don't laugh very All right. So why is mastication
40:17 ? Why did mom say chew your ? All right. Because did,
40:21 , your mom, did she just your food? Chew it?
40:24 take 20 bites before you swallow that of thing? No. Yeah.
40:29 . All right. First off, is highly co ordinated. Have you
40:36 bitten the inside of your mouth or tongue while you're chewing? Like you
40:39 so excited about what you're eating Like you bite the inside of your
40:41 and then once you bite the inside your mouth, it's like you can't
40:44 biting the inside of your mouth. it is a coordinate effort. It's
40:48 idea of being able to chomp down still not bite on the other
40:53 They are the mastication center. It's in the medulla in the ponds and
40:56 it does, it ensures that as chewing, you are moving and manipulating
41:00 lips and your tongue to ensure that stuff isn't going on as long as
41:04 biting them. Now, in terms why it's important. First off,
41:07 increasing the surface area of food. I'm increasing surface area, I'm increasing
41:12 an environment where I can add more more enzymes. So that's number
41:15 That's why I want to break this down. It allows you to mix
41:20 , which we're gonna talk about here just a moment which contains a whole
41:22 of digestive enzymes with that food. it's a mixing process. All
41:29 It also helps to soften moisten food swallowing. All right. I hate
41:37 ask this question because I know the . Anyone here eating like Doritos so
41:40 that it was like sideways and you like in and it jammed up in
41:44 top of your palate. Yeah. . Just I'm, I just wanna
41:48 sure I'm not the only one that's the whole reason I come to this
41:51 . It's therapy. It's like I'm the only person that's gone through.
41:55 right. It also stimulates the taste . Have you noticed that food tastes
42:00 ? All right now. I see people looking at me like I don't
42:03 to admit that I actually dated a in college. My freshman year,
42:07 , I dated her my entire college . But my freshman year when I
42:10 her, she did not understand that had a component to it. That
42:15 pleasurable. Like, tasted good. ate food because if I don't eat
42:21 , I will die. And then started dating me and she learned the
42:25 of food. Food is awesome. we were in New Orleans. So
42:28 learned that food was awesome in New , which is the best way to
42:32 about food. All right, it the taste buds. I'm gonna show
42:36 how stupid a man I am. right, because this is where I
42:40 off on my wild tangents. All , I may have told this story
42:44 . So, um, on uh some of the instructional faculty usually
42:49 together and we have lunch and we about you all. Uh and we
42:51 say good things. We never say things. But one day, Doctor
42:55 , you know who Doctor Cheek Right? She showed up late and
42:58 was all excited. She says, , I'm so sorry, I'm
43:01 I was over in front of the and there was a red tailed hawk
43:04 a squirrel, right? And we're , oh, that's so cool
43:08 you know, we're biologists and stuff that. It's cool. And in
43:12 ignorance, I said, I can understand how animals can eat like raw
43:21 and just kind of rip them apart consume them. And she looks at
43:23 like, I'm the dumbest person on planet. And I was at that
43:26 because I wasn't thinking just because of taste buds, right? Their taste
43:30 are informing them that the things that eating are protein and that protein is
43:34 pleasurable, right? So that's what actually drives a lot of our our
43:40 is that we're getting the things that body wants. Maybe you've heard like
43:46 example, pregnant ladies like to eat stuff like ice cream and pickles,
43:50 ? And what do, why do want that? It's the fats and
43:52 in terms of the pickle of the and probably the acidity just as an
43:58 and what it is, it's the buds. And so that's important to
44:01 your taste buds so that you consume food. So there I'm I'm not
44:07 the smartest man in the room. the dumbest chewing is mostly voluntary.
44:13 a rhythmic reflex. Um uh though so once you start it, it
44:18 just go through the process. This where I look around the room.
44:21 I see anyone chewing gum? I see people chewing gum. But the
44:24 is if you watch someone chew it's like chew, chew,
44:27 you just, you don't have to . Must, you don't do
44:31 It's a reflex that happens just by down. So it's the pressure of
44:35 food in the, in the oral that allows that we're gonna learn
44:39 Now, this is applicable to the as well, what we're seeing up
44:43 . All right. So, the glands have two basic structures to
44:47 We have uh ascena, we have . So here you can see these
44:52 the duct works. The little tiny egg like structures here, those are
44:56 athena inside the are making up the of the ascena. Those are asar
45:01 making up the walls of the So they're duct cells. I'm gonna
45:04 sure I'm saying duct, not quack duck. All right. So
45:09 cells are responsible for producing a serious that contains an enzyme called amylase.
45:15 you ever heard of amylase? What amylase digest? See, carbohydrates?
45:22 . So we have a salivary amylase our mouth that breaks down carbohydrates.
45:28 let's go ahead and jam that lasagna our mouth. And what's the first
45:32 we begin doing when we start chewing lasagna start secreting the amylase when we
45:37 breaking down the carbs of the noodles whatever the carbs in, in the
45:42 stuff that's there. So when I digest begins in the mouth, it's
45:47 just about mastication. We're actually going chemical digestion as well because of the
45:51 of the amylase we also have cells are gonna produce this fluid that contains
45:56 it. Mucin, mucin is the component that makes mucous. So when
46:01 think of mucous, it has All right. So we're creating this
46:06 sticky material that contains an enzyme that me break down the sugars that are
46:12 in the mouth. All right, duct cells on the other hand,
46:17 gonna produce a hypotonic solution containing potassium . And so the person of a
46:22 the purpose of bicarbonate is to What think in terms of like,
46:29 if I have an upset stomach, do I take bicarbonate? Right.
46:34 it reduces the acidity. So most the food that we're gonna eat is
46:38 reduce the acid of the food that eating. It also contains in it
46:44 . Do you know what lysozyme does bacteria to break apart? It's a
46:52 enzyme to destroy bacteria. Five second works why we're already protected?
47:02 And then the last thing is Igaig is the immunoglobulin. It's just an
47:06 that is uh we secreted primarily on surface of the body. And so
47:11 the mouth again, I'm protecting against foreign invasion. Now, all this
47:14 gonna be regulated through the parasympathetic So we got or not parasympathetic through
47:19 A NS parasympathetic is one that increases whereas sympathetic increases flow, which seems
47:25 of like, wait a second. not sure what you're talking about.
47:28 what ends up happening is, is get less secretion while I have sympathetic
47:32 , but I keep the materials right? So think about when you
47:37 a public speech, right? If , if that makes you nervous,
47:41 system is gonna be dominant, sympathetic what is one of the characteristics of
47:47 nervous and talking besides sweating, profusely un coordinating? What's one of the
47:55 dry mouth? We noted that, you, when you talk publicly,
48:01 see people doing the lizard lips, ? It's because their mouth is drying
48:07 . They're not getting the same amount secretion, but they're still getting
48:12 It's just thicker and grosser and Now, we have different types of
48:21 glands over here on the side. are your pros you have underneath your
48:25 . That's the sublingual. You are with the sublingual. Have you ever
48:29 hi to somebody and squirted them like spitting cobra? Ok. That's the
48:34 gland. All right. And then last one is the submandibular glands.
48:39 these are back over here. They're the uh the lymph nodes. So
48:43 just sit underneath, all right. all three of them are active and
48:46 secrete different things. And I'm not I, I ask you to be
48:50 , so clear about this, but just wanted to just kind of demonstrate
48:53 we have those that are serous, are serum mucosal and those that are
48:57 , meaning that they secrete differently. , the minor salivary glands are the
49:02 ones. They're the ones that give the sticky stuff. And so they're
49:05 even labeled up here, right? the serum mucosal has watery plus sticky
49:12 it and then the serous is the . So, think about like when
49:17 have uh a lemonhead, you had lemonhead. Yeah. Or atomic
49:24 Not atomic fireball, sorry, atomic . Anything that makes you go.
49:28 . And what do you get? get that squirt of watery mucus out
49:32 side, you can actually feel your like there's someone squeezing them,
49:36 Those are your parades. All And then the ones that are down
49:40 , those are a little bit thicker terms of the type of uh,
49:43 sal saliva that they make. if you look at saliva, what
49:47 it? It's mostly water about 99.5% . But why is saliva gross?
49:53 do you think? I mean, you think saliva is gross?
49:57 it's kind of gross. Yeah, because it's somebody else's water,
50:02 Your water is gross. My water awesome, right? But relatively speaking
50:07 you. Yeah, it's exactly the . So it's almost all water plus
50:14 plus some proteins. And the key I want you to do here is
50:17 about the amylase. All right. we got the amylase check. The
50:22 enzyme that it produces is salivary lip . So we begin digesting fats in
50:30 mouth. All right. So we the process of digestion in the
50:36 We're digesting sugars, we're digesting And then the other components are the
50:40 lys I, the IJ a little of the nucleic acids. So there's
50:44 Riman nla there. Um And um, the lactoperoxidase, I can't
50:49 exactly what it does. I'm not gonna bother. But anyway, those
50:52 the key ones right there. The and Li Li Ase are the ones
50:54 I want you to walk away All right. Um The type of
50:58 and types of proteins it has are are called pro prolene lit rich.
51:02 so it just kind of shows you they do. They're antimicrobial anti
51:06 they're lubricating. Would it make sense you're wanting to lubricate food in your
51:11 before you swallow it? Ok. . Right. And they reinforce your
51:20 , think about your Oreos, Reinforce those teeth. All right,
51:26 terms of functionality, solvent for So it creates an environment where you
51:30 actually digest the materials, helps you stimulate your taste buds. Because now
51:34 little tiny micro molecules that you're creating able to bind up to the salivary
51:39 to the taste buds, aids and , we've already talked about, you
51:42 , being able to talk clearly and when you have lots of sali or
51:46 not say lots of saliva because that's you're starting doing to do the FVE
51:50 now. I, I can't do right now. But you know the
51:54 of, I don't want to spit people but normal production mouth uh and
51:59 clean. Uh Again, here's a experiment. You can go do
52:02 go get a small pack of go eat the Oreos and then look
52:06 the mirror and then go and sit and do nothing for about five
52:10 Go back and look in the mirror and you'll see that your teeth are
52:14 . It helps to wash down materials your teeth. All right, helps
52:18 to neutralize the acids. Again, was a result of the potassium bicarbonate
52:23 being produced by the duct cells. it also helps to keep your mouth
52:27 . So those are the functions of . Now, you're always producing
52:36 If you've ever been around a young , you probably have seen this much
52:41 clearly. The difference between you and very young child is that you swallow
52:45 saliva, they just let it flow they can, right? So we
52:52 what is referred to as a simple reflex. This is when the chemo
52:57 detect food in the mouth or anything in the mouth. If you ever
53:00 like a really, really dry you wanna make yourself salivate drop in
53:05 lemon head drop in a piece of and your brain will say let it
53:11 and you will get saliva, all , pressure in the mouth. So
53:17 you're doing is basically saying when the of food comes in my mouth,
53:20 begin salivating. That's the simple And then we have the condition
53:25 That's what when we talk about that's what we're referring to. We
53:29 need oral stimulation. Something else stimulates response, swallowing is an all or
53:40 reflex. In other words, you swallow or you do not.
53:46 What you're doing is you're pushing things the back of the throat. Do
53:50 like the, the Homer picture has happened to you? Yeah.
53:57 Yeah. What you're doing is you're push, push the bolus of
54:01 The thing that you've been mani manipulating in your mouth. I can't believe
54:04 have to explain this, but it's the class, right? Because we
54:06 know how to swallow right? When put food in, it goes
54:09 Um Except though I'll just give the of when it didn't. And so
54:13 see in reference to this again, learned how to eat good food in
54:17 Orleans. But the one thing I not eat, ever, ever,
54:20 are the living boogers of the universe are oysters. Uh No, not
54:26 happen. I've, I've done it it was not the most fun experience
54:31 ever had. See what happens is get that bolus of food and what
54:34 gonna do is, you're gonna push back towards the throat. So it's
54:38 in the oral cavity and you're now to the oropharynx. And then once
54:42 get it past that oropharynx, you're go and you're gonna create a,
54:47 response for the muscle, pushes it into the laryngo and then down through
54:52 esophagus, if you can get it the oropharynx, you are good to
54:57 . But if you cannot get it the Oropharynx, it isn't gonna
55:00 This is when I say all or . Right. And so you can
55:03 with these living boogers, right? just put that in there and it
55:06 , I pushed it back and it just like, it is not gonna
55:08 , it's just gonna sit there and would, I was like a little
55:11 like mm mm No. Yeah. , it, it took a long
55:18 and about a half a bottle of and probably seven beers before it.
55:22 right. And then finally it was down. I said, OK,
55:24 done it. That's it. All . So the oropharyngeal stage is that
55:30 stage? All right. It lasts a second. It's just the,
55:32 the part when you're swallowing when you and then that's how it keeps on
55:39 down. Once you get that bolus food into the esophagus, now you're
55:43 the esopha esophageal stage or the esop , esophageal stage. Um And this
55:48 what takes a little bit longer and just moving it down to the
55:51 So this is just all the different of the oropharyngeal stage. We're not
55:54 go through them all. Just if want to see, what am I
55:57 about moving here to, here, to back there manipulating the tongue.
56:02 it pushes it back, that sort stuff. That's what's in that list
56:05 the esophageal stage. Um What you're now is you're creating a peristaltic wave
56:11 is driving that bullets forward. So it gets there and then now you're
56:15 and you're just pushing that bullets downward the stomach and then when it gets
56:19 that sphincter, right? The esophageal gastric sphincter that opens up and it
56:25 allows the food to enter in. go back to that peanut butter sandwich
56:32 got stuck at the top of your . Have you ever noticed when you
56:35 just that big thick peanut butter It kind of gets stuck sometimes right
56:40 . And it's like the, you , you ever eaten food like
56:45 One person is not. Yeah, just making sure like I said,
56:48 is my therapy, you know, know I'm not the only person.
56:53 . Now, what's going on here literally that bolus is actually stuck.
56:57 what happens is that peristaltic wave goes the bolus and doesn't push and
57:01 now you have food stuck in the . And so that's not acceptable.
57:06 a bad thing. And so this when we're gonna create stronger waves.
57:10 so what you do is you actually pushing it down and you get these
57:14 waves that are just driving it That's why it will eventually move
57:18 So if you get stuck, it's stuck there permanently, you're gonna work
57:23 out through the secondary waves that takes to our first interesting structure. The
57:33 . Now, I'm gonna pause here I go into the stomach. I'm
57:35 gonna catch us up. Make sure all on the same page.
57:38 in the mouth, what are we ? Are we doing any mortality?
57:43 you moving things in the mouth? . OK. So think about the
57:47 of motility that you're doing, you're food, mixing food and saliva and
57:52 you're creating the beginning of the swallow you move things through the pharynx,
57:56 . You can say you have motility oropharynx, pharyngeal phase. All
57:59 in terms of absorption is any absorbing taking place in the mouth.
58:06 any secretion. Yes, any Yes. So remember we're digesting lipids
58:15 we're digesting sugars. All right. remember, digestion is, and we're
58:22 doing mechanical digestion. The chewing is mechanical digestion. All right,
58:29 motility. Yes, absorption, no . You can go ahead and say
58:38 . But the truth is you're secreting is to create a slip and
58:41 So that materials go down All I'm not even talking about the folds
58:45 , but the folds actually go lengthwise the esophagus. I'm not gonna ask
58:51 that. But you remember I told about folds in the mouth, the
58:54 in the esophagus are this way. you push, go down like a
58:58 instead of hitting speed bumps. Uh So we got motility, absorption
59:04 . Is there any digestion in the ? No, no, nothing
59:09 You're continuing the process of digestion that in the mouth. All right.
59:14 when you arrive in the stomach, now dealing with a different structure.
59:17 moved past the sphincter. So we have a sphincter here. That's why
59:21 say what happens in the esophagus. go out of the esophagus, we
59:24 into the stomach, the stomach anatomically four areas. We have the
59:28 That's where you enter in to the or into the stomach. You don't
59:32 any acid producing cells there. So not really going to do a lot
59:37 digesting digestion in the cardia, then have this region. So if you
59:41 at where the esophagus enters in, to where that sphincter is located,
59:45 region of the stomach that extends upward called the fungus. So the fungus
59:50 a storage area, lack of a term for it. All right,
59:53 basically is responsible for taking food and of putting it over here to the
59:59 until the process of digestion begins. right. On my slide, I
60:03 the smooth muscle here is, is thin. This is gonna become important
60:07 just a moment. We have the , the body is really the majority
60:13 the stomach. And here the smooth which start off thin and the fungus
60:17 becoming thicker and thicker along the All right. And then you get
60:22 to the Antrim and the Antrim is region nearest the pyloric, the pylori
60:27 the pyloric sphincter. And here the is gonna be the thickest. So
60:32 start off very thin and then you out this way and you get thicker
60:35 thicker until you're down here at the where it's the thickest. Now,
60:39 regard to the stomach, the stomach multiple rolls, it stores up food
60:42 it can be emptied out into the intestine for absorption and digestion. The
60:48 plays a role in digestion. It hydrochloric acid and a couple of enzymes
60:56 are going to begin the process of digestion and going to aid in the
61:01 of some digestion here in a little here. And lastly, it plays
61:05 role in mechanical digestion because you're gonna pulverizing food. It has a role
61:09 motility by mixing food with the materials it's secreting. And ultimately, it's
61:14 move that food that is broken down its almost smallest components into the small
61:19 to finish the process of digestion before takes place. So it has a
61:24 in secretion. It has motility, has no absorption, but it does
61:29 digestion. Yeah. OK. This sphincter right here. Yes.
61:36 both of them. Yeah. So of these are going, are going
61:39 be stretched in response to some sort motility or some other sort of external
61:45 . All right. So the first we need to know about the
61:51 especially since Thanksgiving is coming up, should know this about ourselves that it
61:57 uh responsive to um food by relaxing . What we refer to as receptive
62:04 . So when you put food in stomach, the stomach doesn't go oop
62:07 squeeze on it. It says uh allows you to put more and more
62:12 in it. So it allows for entry of food into the stomach.
62:15 is what is controlled through what the vagal resets or reflex. So it's
62:22 see the vagus nerve and how it responsible for controlling this through the autonomic
62:27 system. Now, what you can here and this is the danger of
62:36 is that you can increase volume without pressure. If you notice that plate
62:42 one is not too bad. Plate two, I can do that and
62:47 number three is now I'm praying for , right? Does that sound about
62:52 ? I'm the only one that eats plates of food at Thanksgiving.
62:56 Get my stretchy pants. You never dress up for Thanksgiving. You
63:01 , you may go over someplace nice make sure you've got the skirt.
63:03 you have to dress up, you the skirt with the stretch in
63:07 right? In terms of accommodation, we're gonna do is we're gonna dilate
63:14 the fungus. So that's what you're is you're basically allowing the food
63:18 uh, uh, show up there it will be stored there and slowly
63:23 into the body and then ultimately to Antrim. Now, remember this is
63:28 hollow structure. This is not like compartmentalized structure. It's not like a
63:33 where we have four chambers. It one big giant open area. But
63:38 way that food is managed in there that it actually holds materials off to
63:42 side and delivers materials from area to . It's kind of cool. All
63:49 . Now, if you get too food in there, um you'll get
63:52 rapid increase of pressure. Um Have ever heard of the gallon milk
63:56 Please don't if you ever see do not ever accept, you know
63:59 the gallon milk ch do not ever this. Do not ever do
64:02 You'll be hating life for about I don't know, six or eight
64:06 . All right. So the reason is that you put this liquid in
64:09 stomach. If you put a gallon water in your stomach, your water
64:12 stomach expands and then it goes down your bloodstream. But if you put
64:15 gallon of milk into your stomach, it is mostly uh uh proteins.
64:20 what will happen is the rennin in stomach will cause that milk to
64:25 And so that liquid becomes solid. now you feel that horrible pressure inside
64:30 belly and there's only two things you do with that. You can pass
64:34 out through the pylos which is gonna some time or you can return it
64:38 whence it came and there's nothing worse throwing up curdled milk. All
64:46 Actually, that's where we discovered Not from throwing up milk. Now
64:50 no, um, someone took a of an animal and said, I'm
64:56 milk in the stomach because I want carry it off to my family or
65:00 . And then they got there and was all curdled and they probably let
65:02 sit there for a while and then was like, hm, this tastes
65:06 . Oh, come on. We like cheese. Most of us like
65:10 . We have it in our All right, in the stomach,
65:15 the body and in the Antrim, you will see are these deep structures
65:19 go up and down. Do I it on the previous slide?
65:22 I don't. Ok. And so is what is referred to as the
65:25 pit. So remember how we talked different folding. So this is how
65:29 mu cosa of the stomach is It creates these pits and within these
65:33 , we have specialized cells and on surface of the mucosa, we have
65:37 specialized cells that play an important role secreting the materials and protecting the stomach
65:43 the secretions that you're actually producing. these are the cells you need to
65:48 you have the mucus neck cells. MS neck cells are located in the
65:53 of the gastric pit. What do think they produce mucus? That's why
65:58 called mucous neck cells. All Now, the type of mucus that
66:01 producing is very, very thin and . All right. So it's more
66:06 a watery type of mucus than a gooey mucus. We have chief
66:11 they're called chief cells because they're the cell, the most common cell.
66:15 right. Whenever I see chief my bigoted brain goes to Indian chiefs
66:19 headdresses. But right, but what do is they produce an enzyme called
66:26 . And pepsinogen is released in its form and secreted into the stomach.
66:31 also secretes gastric lipase. So, role, what job does the stomach
66:37 in digestion? Well, right it just tells you lipase, four
66:47 , the pepsinogen, we didn't really it. So I apologize. It's
66:51 . So, proteins and fats. that's that sugar that we began
66:57 We no longer gonna digest. We're a unique environment because the parietal cells
67:01 producing hydrochloric acid and that ph change the activity of the amylase. But
67:08 continue the process of the fat Because of the um the gastric lipase
67:13 we're producing, we have stem stem cells do what produce other
67:18 So they're responsible for making the other . We have these epithelial cells.
67:22 job is to produce a very thick mucus. And then we have endocrine
67:27 , a variety of different types that gonna be secreting back towards the blood
67:32 so that we can send signals to to the digestive system. What is
67:37 on? Now, this is where gonna be in the body and the
67:41 , when you get down to the region, the Antrim lacks um the
67:47 cells. Actually, I think it a parietal cells that just doesn't produce
67:50 acid. So um the other thing there is intrinsic factor, which
67:54 is important for uh vitamin B one , but I don't think I ever
67:59 that. All right. So let's about what these things are and why
68:04 have them. Why do we care hydrochloric acid? What you're doing is
68:07 changing the ph of the stomach and changing the ph what you're doing is
68:11 telling proteins, what you've already begun apart through mechanical means is you're now
68:17 an environment for them to dissociate and up. And when, if I
68:21 a, a globular protein that's like and I open it up. I've
68:25 revealed its secondary structure. Right. , it's primary structure. Excuse
68:31 And if I have primary structure, means my enzymes can now cleave at
68:37 locations wherever it's where it's meant to . All right. So how do
68:44 make this? Well, I use anhydrase. Let's see. Where do
68:48 see carbonic anhydrase before? Have we this yet? Oh, we have
68:54 . What do we do? We carbon dioxide plus hydrochloro or plus
68:58 Carbonic anhydrase makes carbonic acid. It and we end up with bicarbonate and
69:05 end up with hydrogen. Hydrogen goes the stomach, bicarbonate goes into the
69:14 . Uh That's why I've got basic , not just the respiratory system involved
69:19 that. All right. So also ph kills micro organisms. It takes
69:25 tissue, it doesn't break, break down, but it causes it to
69:30 bonds like hydrogen bonds with other So it opens everything up. So
69:35 makes it easier to digest the Pepsinogen is an inactive enzyme and the
69:42 it's inactive because it is a peptidase is break down peptides. Or
69:49 it a pro prose? I can't what I call it here. It's
69:52 pepto dase. All right. Peptidase little bits and pieces of protein.
69:58 are you made up of proteins? , if I have it in my
70:02 that made it right? If it's the chief cell and it made
70:06 and it's filled with proteins. Then active enzyme would just destroy the chief
70:12 . So I have to create it an inactive form, release it and
70:15 let it be converted into its active . So, pepsinogen is inactive,
70:20 released and the environment that Ph causes to self lice and it turns the
70:28 into pepsin and then Pepsin can break other things. But the other thing
70:32 it does is it creates a positive back loop to activate more pepsinogen into
70:38 . All right. And what it is you start breaking things down and
70:44 things that are called pep toes. my mind. When I hear a
70:48 , it sounds like a singing No, the peptone does not sound
70:54 gav from the fifties, maybe. . So these pep tos are,
71:01 important because it's in, it's an of the activity of the stomach,
71:07 things down. And so it's used a signaling system or a a,
71:12 molecule that we're gonna be detecting in to activate a couple of other
71:16 So, what are we going to ? We're going to stimulate the production
71:19 gastro gastric is produced by one of endocrine cells called a G cell.
71:26 not too hard. Is it G gastric and it's releasing gastric into the
71:32 so that we can signal to a of different places. We're gonna be
71:36 back to the stomach, but we're gonna be signaling to the small
71:40 Second thing it's gonna do is it's to signal the presence of uh peptone
71:46 that KK is the name that we the fluid that's water. Plus the
71:51 that we're digesting when it arrives in duodenum. There are cells called eye
71:56 and they produce a uh uh endocrine or a signaling molecule called cholecystokinin CCK
72:04 its abbreviation cholecystokinin. All right. it does very much the same thing
72:09 gastro does, but it's acting from duodenum. So the duodenum is basically
72:14 , hey, we have peptone, the process of digestion going. And
72:19 we also are going to promote hydrochloric secretion because we need to have environment
72:23 order to ensure that the digestion is place and that the proteins are opening
72:27 so that I can digest. So of the signal here, the presence
72:31 these peptone is ensuring that the uh only the chief cells, but the
72:35 cells are being functional when Pepsin gets environment that has a much higher.
72:42 7.5 I turn off my Pepsin. what do you think is happening in
72:47 Dewana? What do you think a in the Du Aum is it's
72:52 So what am I doing in the autumn? I'm turning off the
72:56 OK. So notice, remember what said is we're dealing with different compartments
73:02 these different sphincters. So as I from one compartment to the next,
73:06 doing something new. So anything that turned on, I'm also turning
73:09 So I turned off the Amylase when arrived in the stomach, right by
73:13 a Ph, that was different. then now the time has a
73:16 much lower ph and then when it to the duodenum, it has a
73:20 higher ph. So the Pepsin gets off and we're going to introduce new
73:25 to it. Now, if you been paying attention, maybe the question
73:32 might have should have asked. Maybe you were like following along,
73:36 wait a second, I'm creating a , really acidic environment. I'm introducing
73:40 that like to break things and I'm thing. And why isn't it breaking
73:45 from the digestive system? Right? , why not eating my way uh
73:50 inward? And the answer is because producing mucus. And we said there
73:54 two different types of mu mucus and was water mucus and thick mucus.
73:59 if you're like me, you start , wait a second, how is
74:02 barrier? If I've got to you know, hydrochloric acid and Pepsin
74:07 have to get through this protective barrier go do its job. Why isn't
74:10 sitting there right next to those cells up the cells? You see
74:17 Do you see the problem? Did not occurred or is, everyone was
74:21 with that. I, OK. , sometimes you, like, maybe
74:26 you're studying late at night, that's you're like, wait a second.
74:29 , the reason that doesn't happen is these cells, these chief cells act
74:36 geysers. All right. And what do is they build up their hydrochloric
74:41 and then they squeeze themselves and they that hydrochloric acid in a little tiny
74:47 through the mucus so that it squirts on the outer side. This is
74:53 we refer to as viscous. Fingering worst naming ever. All right.
75:00 that's what it does. So what trying to show you is like you're
75:03 producing and it goes and little And so what you're doing is that
75:09 might create a little tiny pathway through mucus. But you're getting the majority
75:14 that hydrochloric acid un neutralized to the where it needs to do its
75:19 So that's the idea. So the that you're producing is a diffusion
75:25 In other words, it prevents the acid and the pepsinogen from getting down
75:31 it. It neutralizes the hydrochloric acid the Pepsin can't get down to digest
75:36 cells because of the layers of the that are in place. One of
75:46 favorite pictures I ever found on the . This is a series of three
75:51 pictures on someone's Facebook page or I don't know where I found it
75:55 they, they had a title for . It says bathing in the blood
75:58 your enemies. Love it. If ever had again, if you have
76:05 little sibling or a cousin, this happen when we fed our babies at
76:11 time. The first time they ever sugar. The look on their
76:15 I mean, it was like they like the cupcake and they were
76:18 and then they were like just shoving and their whole face was like
76:21 So, yeah, so how do regulate all these processes? All
76:27 So we have pacemaker cells. So we're doing is when we're talking about
76:32 , they're basically creating a rhythm of and a regu regu regular contraction in
76:39 digestive tract. So there are gonna some nervous reflex that are gonna alter
76:43 force but not the rate of All right, that's constant. So
76:49 can think of it like this. stomach is always doing this and if
76:54 want to make it work more, I'm really doing is I'm just making
76:58 contractions. All right. There are phases, two gastric regulation. There's
77:05 before and during meals, the two during meals are cephalic phase and the
77:09 phase. And this is followed by after meal, which is the intestinal
77:14 , the hormones of which there are , we're looking at three gastric we've
77:20 mentioned is secreted by the G It goes into the blood and acts
77:25 the body and on the fungus of stomach. Its job is to promote
77:30 by acting on the parietal and the cells. Ok. So they're promoting
77:35 activity. How do we stimulate this from the nervous system? We're gonna
77:41 uh GRP which is gastro releasing peptide a uh signaling molecule. And also
77:48 presence of those peptides in the stomach what causes the release of uh gastric
77:54 two is histamine. We all heard histamine histamine. In this case is
77:58 signaling molecule. It's produced by these cells, these intero chromo fin like
78:04 um and what they do is they promoting the process of digestion. All
78:10 . So two promoters see them gastro , it increases hydrochloric acid secretion.
78:19 it's acting on the chief cells. one is somatostatin. There's a third
78:27 , another type of cell here called cell. The D cell is what's
78:29 producing the somatostatin. This is the regulator of the gas pedals. So
78:35 your break. These two are gas really what these are doing are just
78:44 you how we go about doing So if you look at the picture
78:47 , here you can see here is enteric nervous system. I am releasing
78:52 , acetylcholine is acting on the uh cells here, the parietal cells producing
78:57 hydrochloric acid. All right. What I doing? Oh I'm releasing
79:02 histamine is acting on the receptors causing production of hydrochloric acid. Oh What
79:08 uh the gastric? Well, gastric coming from the G cells, the
79:13 cells or uh the inter chromo fin , they can act on either way
79:18 it's promoting production of hydrochloric acid. these are direct pathways if I'm acting
79:24 the cell directly, if I'm acting like the E cell cells, that
79:29 cause that production, that would be , that should be pretty straightforward.
79:34 when it comes to cephalic, which really the key thing and then we
79:38 , I, I'll just leave this . I will because we'll do
79:42 we'll do gastric, we'll do intestinal it'll all make sense because it's all
79:47 . Right. So, have a weekend. What weekend is this
79:54 Paint yourself red, behave uncontrollably, , uncontrollably. Oh. Also,
80:04 to
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