BAP Digestive system part one 20161118 095438 17

BAP Digestive system part one   20161118 095438 17

– [Teacher] System. We have our two groups of organs. Again, this is completely wrong. The GI tract is down here. So this what we call the GI tract. GI tract is stomach and intestines. Now the entire thing is
called the alimentary tract. Alimentary tract. So the alimentary tract
or the digestive system, we start with the oral cavity and then we have the
pharynx, the esophagus, stomach, small intestine, large intestine. All of these are the alimentary tract or the digestive tract. But the GI tract is only the
stomach and the intestines. So that’s something that we wanna clarify and make sure you guys have that down. So GI tract is specifically stomach, small intestine, large intestine. All right, now, along with
the alimentary tract organs, we have the accessory digestive organs. Now, the accessory organs
would be like the tongue and the teeth and the salivary glands. So tongue, the teeth, the salivary glands, these are all accessory organs. They help with digestion
and metabolism of the foods. And then down here we have the liver, we have the gallbladder, and
then we have the pancreas. These are all of our accessory organs. They help with digestions,
they help with metabolism of what we ingest. We talked about this way back
at the beginning of class, but when you eat something, so something’s in your mouth
or something’s in your stomach or something’s in your intestines, is it actually in you? (inaudible) – [Student] Not until it’s digested. – [Teacher] Not until it’s digested. And what’s the next step? Okay, so digestion is
just breaking it down. But it’s not in you until what happens? All right, so you’re right. Remember what’s the next step? – [Student] Go into your blood stream. – [Teacher] All right, it
goes into your blood stream, call that absorption. When we look at the food
and the food material, the food material is not actually
in us until it’s absorbed and then metabolized by the body. So we’re gonna talk about
that and how that relates and why that might be significant. Here’s the alimentary tract, the hollow tube from mouth to anus. Now, the primary functions
here of the alimentary tract are, number one, digest the food, number two, absorb the food. Now, digestion is a breakdown process. If we remember this from back
in the first day of class, we talked about breaking things down and we called those catabolism
or catabolic reactions. Now, building things up are called what? (student speaks indistinctly)
Anabolic, okay. I think of anabolic
steroids, they build muscles. So anabolic means building things up. Now, step three is ridding the
body of undigestible waste. This isn’t from your cells,
this isn’t metabolic waste. This is just undigestible foodstuffs. So we think about defecation, all we’re doing is eliminating
the alimentary tract from what we can’t absorb. Now, the accessory organs
help with digestion and they help with metabolism. Metabolism is how we
process the food steps. The big one here is the liver. Your liver is the largest visceral organ, the largest visceral organ in your body. It’s responsible for
metabolizing everything that we absorb through
our alimentary tract. We’ll talk about that more
towards the end of the lecture. All right, now, when we look at the steps or the events of digestion, the first event is when you take some food and you put it in your mouth. We call that ingestion. You ingest some food. Now, ingestion is a
voluntary process, right? You choose. Maybe not so much when
you’re, like, an infant. An infant, you know, you pretty much just, you eat whatever is given to you, right? But as you get older, then
you choose what you wanna eat. So a two-year-old doesn’t
wanna eat those Cheerios, what happens to those Cheerios? (vocalizes flying sound)
All over the place, right? Just throw ’em everywhere. And if you have a dog, that’s even better because then you just
throw them down to the dog. Now, mechanical digestion takes place as soon as we put food in the mouth. We talk about this as mastication. Mastication is chewing. Masticating is chewing. Now, your oral cavity is designed for the mastication process. Mastication tears the
food into small pieces using your teeth. And then, at the same time, your tongue helps to
mix the food with saliva and that initiates chemical digestion. Both of these are important and they both happen together. All right, they both
happen simultaneously. As soon as you put
something in your mouth, you start to salivate. Saliva contains enzymes and water, right, mostly water, 99% water. But it does contain enzymes
that mix with the food and immediately begins chemical digestion. Now, mechanical digestion
again is extremely important because it tears apart the food, increasing the surface area so that chemical
digestion can work better. Again, increases the surface area so chemical digestion can work better. If you don’t chew it, it’s
not gonna get digested, right? Okay. You guys have a dog, anybody have a dog? Yeah? When your dog swallows something whole, it usually comes out the
other end whole, right? Very little digestion occurs
unless we chew our food. Now we look at chemical digestion, water is a solvent. So water does help to break down your food to a certain degree, but then
we have all kinds of enzymes. We have lots and lots of enzymes in our saliva, in our stomach,
in our small intestine. Enzymatic breakdown is called hydrolysis. Hydrolysis is the breakdown
of food through enzymes. Enzymatic breakdown of food is imperative, especially for protein digestion. Proteins are typically
very, very large molecules. For our body to absorb them, they have to be broken
down into amino acids. You guys remember this from way back at the beginning of class, proteins are made from the
building blocks amino acids. Those are the ones that
we can actually absorb through the lining of
our alimentary tract. So we needs lots of enzymes to help break down our
food, especially proteins. Now, once we break down the food into the smallest particle, then we can absorb the nutrients through the lining of our small intestine or through the different
areas of our alimentary tract. At the very end of things we
have this process, defecation, which eliminates undigestible
food from the body. Now, propulsion is a separate event. This is not necessarily
an event of digestion, but it is a very unique process that we see along the alimentary tract. Now, the propulsion from
one place to the next is done through a very unique
movement known as peristalsis. Peristalsis helps to propel food from one place to the other. So we have this unique
specialized contraction called peristalsis that pushes the food from one point into the next. Now, the easiest way to
understand peristalsis is, think about swallowing. Swallowing is referred to as deglutition. That’s like the fancy term for swallowing. But when you swallow, you can feel it go from the back of your throat and you can kind of feel it go all the way down into your stomach. So it’s a wave-like contraction that propels food or liquid
from one point until the next. Now, we see peristalsis in
other parts of our body, we see it in the urinary and
reproductive systems, as well. But for the most part, the peristaltic activity is used extensively through the digestive system. All right, so these are
the different events. You guys have any questions on those? Not so much yet? All right, you guys all
practice ingestion today? Abby, did you have a good breakfast? No.
Did you eat any breakfast? No.
No? Man. All right. Now, when we look at the
control and regulation, the digestion is controlled and regulated through the parasympathetic
nervous system. You got your parasympathetic
nervous system, your PSNS. The parasympathetic
nervous system reaches out to all of our internal organs. The part that specifically reaches out to the digestive system is called the enteric nervous system. This is the one that directly innervates the gastrointestinal
tract plus the esophagus. Basically from your esophagus to the anus, the parasympathetic
nervous system innervates that section or those sections. Again, we call that specific part the enteric nervous system. This controls all of
the glandular secretions and the movements and hormone release. The parasympathetic
nervous system secretes a number of different hormones that help to control and regulate what goes on here in your digestive tract. Now, when we look at the
parasympathetic nervous system, parasympathetic nervous
system is primarily reflex. Now, this was proven
through the studies done by Pavlov and his dogs, right? He would condition them to expect food when he rang a little bell. So he’d ring a little
bell and feed the dogs and then the dogs would eat. He did that for a while,
then he’d ring a bell and he wouldn’t do anything and he would watch the
visceral reactions of the dog. The dog would be expecting food, the dog would start salivating. That’s a reflex action initiated through the parasympathetic
nervous system. Now, another example of
that reflex is swallowing, is that peristaltic wave. Now, do you voluntarily
initiate the peristaltic wave or does it happen all by itself? What do you think Morgan? Just happens.
It just happens, right. What about the churning of your stomach, does it just happen? It just happens, right? The churning just happens. You don’t think about it. It’s not like, “Okay, hold on. “Gotta take a break, you
gotta churn some food now.” It’s not that you have to do that. It happens automatically. It’s a reflex. When we look at reflexes, and if you guys remember
this a little bit, we had this on a quiz in
regards to the nervous system, receptors are what initiate a reflex. So we have these receptors that initiate these reflex actions of your digestive system. Now, these receptors are
sensitive to chemicals and they’re sensitive to stretching or distension of your different parts. Think about a chemical receptor that you might have in your oral cavity. What do you think, Molly? – [Molly] Can you say that again? – [Teacher] What’s a chemical receptor you have in your mouth? Chemicals? Nothing? What do you think, Jess? – [Jess] Salivary gland? – [Teacher] Well, that’s a gland. What’s a receptor, chemical receptor, on the surface of your tongue? Taste buds?
All right, taste buds. So we have these receptors, taste buds. Taste buds are a great example of these chemical receptors. As soon as you put something in your mouth that has any type of taste,
any type of chemical in it, you immediately start
to stimulate the actions that we see here of the
enteric nervous system. You immediately start to salivate. Even if it doesn’t taste very
good, you start salivating. Now, when your esophagus stretches, that’s a stretch or that’s a distention, and your esophagus immediately contracts and creates a peristaltic wave. Or when your stomach stretches out, you start to churn, your
stomach starts to churn and grind up the food, mix
it with acids and enzymes. So the receptors are located in the walls of the
alimentary tract organs and again sensitive to chemicals and distention or stretching. Yes, Francisco? – [Francisco] Could
you go over PSNS again? – [Teacher] All right, PSNS is parasympathetic nervous system. So parasympathetic nervous system. You guys remember the nickname of the parasympathetic nervous system? Remember that, Morgan? Fight or flight?
No, no. (student speaks indistinctly) All right, that’s the rest and digest. So sympathetic is fight or flight, and that shuts off your digestion, right? Shuts off digestion. But then we have the
parasympathetic nervous system. That’s the part called the
rest and digest system. All right.
Does that make sense? Yeah.
Okay. That’s the one that controls
all of our digestion activity. That’s what makes you tired, right? It makes you tired after you eat. So after Thanksgiving this week, you guys have Thanksgiving dinner? Or lunch, whatever you guys do? You always wanna, like, try and take a nap afterwards, right? It’s not always the turkey. How many of you guys have,
like, ham on Thanksgiving? All right, so you guys have ham? (student speaks indistinctly) All right, how many of you guys have, like, just a big, giant chicken? No? How about a turducken? (laughs) You guys know what I’m talking about? All right. – [Student] We had that once. – [Teacher] Yeah? – [Student] It was different tasting, to say the least. – [Teacher] Yeah? (chuckles) I don’t know, I’ve never had duck. But I hear you have to have
a taste for it, apparently. Either you really like it
or you really don’t like it. Any of you guys eat duck? Never have before? Yeah, yeah. My cousin, well, brother-in-law, they shoot duck all the time. So yeah, I don’t know. The only birds that I
ever really liked to eat were pheasants and quail. They tasted really good. But never had any duck. How about you, Abby? No duck? Uh-uh.
All right. When you look at the alimentary tract, there’s four distinct layers that we see. We have the mucosa. The mucosa is the internal lining. This is the lining. Now, because we’re talking
about a mucous membrane, what do we normally find
in mucous membranes? Why do we call it a mucous membrane? What do you think, Elena? – [Elena] Because it helps prevent friction? – [Teacher] Well, what does? The mucus.
The mucus, okay. Mucus is the key, right? Now, you guys remember the
cells that produce mucus in the respiratory system? Goblet cells.
Goblet cells. All right, should have had
that on the quiz, right? We look at mucosal lining, again we have all kinds
of goblet cells in here. We see those again here
in the alimentary tract. So all these goblet
cells, they produce mucus. And as mucus lubricates the
lining of the alimentary tract and it also helps to keep you from digesting yourself, really. So it protects you from digesting yourself with all of those enzymes and
the acids that we produce. Now, the second layer
is called the submucosa. The first layer, mucosa,
second layer, submucosa. Now the submucosa, this is
where we find lots of nerves and blood vessels. So nerves and blood vessels are found in the submucosal layer. Number three is the muscularis layer. We have the muscularis layer. When we look at the
muscle, the muscular layer, we have two layers. We have circular layer, number one, that’s number one. And then number two or b there is, we have a longitudinal layer. So we have two layers, a
circular layer on the inside and a longitudinal layer on the outside. Okay now, these are the two layers, this muscularis layer, these are the two layers
that create peristalsis. They contract simultaneously and this produces that wave-like motion that propels the food from
one point into the next. Now, the fourth layer, number four, is what we refer to as the serosa. Okay, the serosa is the outer covering. Now this is only found in the GI tract. We only have a serosa in
the gastrointestinal tract, in the GI tract. That mucosa, let’s just talk about the mucosa just a little bit. We look at the mucosa. We have this mucosa
starting in the oral cavity, so it starts in your mouth, and it goes all the way down to the anus. Now, the mucosa has different
jobs in different areas. The mucosa in your mouth
and your esophagus, it protects you against friction, protects you against
friction in those two areas because of the chewing and
the swallowing process. In the stomach, we see a very,
very thick, very thick mucus to protect you against
the acid in the stomach. But then we get into the
small and large intestines. The small and large intestines, the mucosa is much more porous, which allows for absorption to take place. In this picture here on the side, it shows you absorption occurring. But again, you only see
that in the small intestine or in the large intestine. In those two areas of the
body, it’s very porous, very porous, which allows
absorption to occur. Almost all absorption takes
place in your small intestine. Now, anatomy, we just talked about these. In the mouth and
esophagus, it’s protective. In the gastrointestinal tract
it’s more for absorption. And we see those goblet cells in there, very, very significant because
they produce the mucus. Then we talk about the submucosa, the muscularis layer, and then the serosa. Now, in the gastrointestinal
tract, so in your abdomen, so think about your stomach
and your intestines, they’re found in your
abdominal and pelvic cavities. Now, lining the abdominal pelvic cavity, we have another serous membrane
known as your peritoneum. The peritoneum is the serous membrane in your abdominal pelvic cavities. Now, why do we have a serous membrane in your abdominal pelvic cavity? What does serous membranes
do? You remember? Remember, Michaela? (student speaks indistinctly) Exactly. Same thing is gonna be here, right? Serous membranes reduce friction. Now, it’s not necessarily as obvious here in the abdominal and pelvic areas. But your stomach, your stomach is moving when you’re churning and
grinding up the food. Your intestines are moving a little bit. Your large intestine moves, especially when you guys defecate. So there is movement here inside your abdominal and pelvic cavity. Plus, think about all the
action that happens down here when you’re ambulating, when you’re walking or running. When you guys are running, stuff is rubbing against
each other down here, right? So we still need that
reduction in friction in your abdominal pelvic area, just like you would see
it in your chest cavity. What were the other two serous membranes? What was the serous
membrane around your heart? Do you remember that one, Jacob? The one around your heart? They all start with a p, if that helps. No? Andrew? Pericardium.
Pericardium. What’s the one around your lungs? Remember that one, Andrew? That’s all right. Logan? The pleura?
Pleura, okay. So those are the p’s. We have the pericardium around the heart, we have the pleura around the lungs, and then we have the peritoneum around the abdominal and pelvic organs. Those all help to reduce friction. Now, the peritoneum forms, as the peritoneum is wrapping
around all these organs, it helps to form some
very unique structures, like the omentum. I’m not worried about the lesser omentum, but I do want you guys to
remember about the greater omentum because it’s so great to have. So we have the greater omentum. Now, the greater omentum is an apron. It’s an apron of fat
that covers your abdomen. It’s like a big apron
of fat that kind of lies right over the top of the abdomen. Now, everybody has a greater omentum. Some are greater than others, though. Do you know anybody who
has a pretty great omentum? They have a rather
distended abdomen, right? Saw this young dude this morning. Typically I don’t
necessarily care about that. But he was a young guy. He’s probably like 25 or 26. Man alive, did he have a huge beer belly. Just a huge, gig-, I mean, it was big. I’m, like, “Dude. “You’re only like 26 years old. “What happens when you’re, like, 50? “You’re gonna be dead, you know?” (students chuckle) I didn’t say that to him, but I’m, like, yeah.
(students laugh) I’m, like, “Dude, man!” But when this greater omentum gets thick, that’s what causes that,
kind of like that paunch or that beer belly. Now, you guys never noticed
that it’s not jiggly. You ever notice that? It’s like hard as a rock. And it’s because this is internal fat. When someone has internal fat, it’s very physiologically hazardous because it means that
the body is struggling to deal with the person’s diet. Typically when someone has
a large greater omentum, we always call it the beer belly. But there’s a lot of guys that drink beer and don’t have this big gut. Typically it’s something else that they’re eating a lot of
of that causes this to happen. Now, it might be a little bit genetic to the idea that their body
handles food differently than other people’s bodies. That make sense? Now, it’s never genetic that someone just has to have a greater
omentum, a big one like that. But the genetic idea or
the understanding comes in is that maybe this person
metabolizes food differently and it just, for some reason
the body stores more of it inside that greater omentum. But what it does mean,
no matter who has it, what it means, though, is that your cholesterol
levels are skyrocketing, you’re gonna end up with
coronary artery disease and your liver is probably
gonna fail at some point. That’s what it means to someone who has that really big greater omentum. Now, I know a lot of guys
who, say, grew up on a farm. Almost all of the older farmer
guys had greater omentums. Some dudes just had a
really great one, you know? They’d always laugh about
it when asked about it. Just like, “Hey, it’s my gas
tank for my love machine.” (chuckles) Ah, so that was, like, you
guys didn’t think it was funny. Maybe a little bit, yeah? Gas tank for love machine,
you never hear that? No? – [Student] We always say it’s the boiler for making (mumbles). – [Teacher] There you go,
the boiler, there you go. Get that momentum going, right? – [Student] Get that big inertia– – [Teacher] Momentum. (chuckles) All right. Another couple structures to make note of is the mesentery and the mesocolon. These are layers of tissue
that hold your small intestine and large intestine in place. Let me show you what that
looks like on the next slide. Here’s a slide where we
do a mid-sagittal cut, so mid-sagittal view of
your small intestine or, I’m sorry, your abdominal pelvic cavity. We can see this stuff here holding your small intestine in place. This stuff right here, these
kinda strips of material. We call ’em the mesentery. That holds your small intestine in place. The reason that this is significant is because you have 10 to
12 feet of small intestine. The average person has 10 to
12 feet of small intestine. That’s from me to Francisco away. That’s a lot of small intestine, right? You would think it would
get twisted up, right? You know, twisted up? But it doesn’t. The mesentery holds it in place
in, like, folds or layers, like layer upon layer upon layer. And it keeps it from
getting all twisted up. That’s really important because you don’t want a twisted gut. Then it’s extremely painful and you have to have
surgery to get it fixed. Any of you guys have a horse or any, like, large animal
that had a twisted gut? It’s not good, right? They don’t feel so hot. So you gotta get the vet in there and they have to cut
it open and untwist it and kinda get the gas out of it, all that kind of stuff, right? (student speaks indistinctly) Yeah, it is interesting. But man alive, I don’t
think that cow or horse or whatever else is really
having all that much fun. The other part is the
mesocolon, the mesocolon. That holds your large intestine in place. So here’s, like, a
little strip right here. We call it mesocolon. You have four to six feet, you have four to six
feet of large intestine kinda wrapping around the outside edges of your abdominal and pelvic cavities. You don’t want that to get all twisted up because you get impacted and you get, you know, a lot of pain, lots and lots, lots of pain. Okay, so those are other membranes or other structures
produced by peritoneum, mesentery, which holds your
small intestine in place, mesocolon, which holds your
large intestine in place. And it’s just some structures
to pay attention to. Here’s what it looks like if you opened up the
abdomen from the front. If we looked at the cadaver, this is basically what you’d see. Here’s that big apron. Here’s that big apron of fat that kinda drapes across the abdomen. Here it’s kind of folded
up for the chest cavity to kinda show you the mesocolon. So here’s the mesocolon and
down here’s the mesentery. So looks like that kind
of membrane in there. Now, it is yellowish, right, because typically it’s full of fat. Now, we’ll look at another
picture of the colon. It’s very interesting. When we open up cadavers,
it’s always interesting to see how much fat
they have on the inside. We had this one guy, we had this one guy who had
a really distended abdomen. And I’m, like, “Man,
we’re gonna get to see “a great, big greater omentum. “And I’ll be able to pull that out “and show the kids and everybody.” When we opened him up, he didn’t have a great,
big greater omentum. I’m, like, “Man!” But he did have liver cancer. They don’t tell us all that stuff. But he had liver cancer and his liver was about 200% larger than
it was supposed to be. So it’s, like, two or three times as big as it’s supposed to be. It took almost all of his
entire abdominal cavity up. So I felt really bad. I felt really bad, like,
“Greater omentum, oh! “Liver cancer, man.” (students and teacher giggle and chuckle) Logan? – [Logan] Greater omentum, is that behind or in front of the liver
and abdominal muscles? – [Teacher] It’s behind the muscles but it’s in front of the intestines. Yep? – [Student] You know
who Brock (mumbles) is? – [Teacher] Yep. You see how his gut it?
Yeah. – [Student] Like, you can see his abs, but his gut, like,
protrudes out really far. That’s why (mumbles)? – [Teacher] Probably not. A lot of times, a lot of times when we look at big guys, like body builders, are into like that. They got, like, a protruding abdomen. You ever notice that? They’re really muscular but they got a protruding abdomen. There’s a few different theories on that. I’m gonna talk about one of them that is probably the most common theory, or at least the most substantial theory. Other theories is that they overtrain their abdominal muscles. So you do, like, I don’t know, you do all kinds of weights and make your abdominal
muscles really thick, but sometimes that can cause that action. But usually it’s something
with the intestines, not necessarily a great omentum but usually something in the intestines that we’re gonna talk about. Okay.
Okay? Any other questions you guys have? All right. That guy’s a beast, eh? Man alive. – [Student] Yeah, his
tattoo’s stupid, though. – [Teacher] What does his tattoo say? – [Student] It’s just a big, like– Knife.
Like a sword? I think a sword or
something like that, right? No? – [Student] I don’t know,
it’s really dumb. (student speaks indistinctly) – [Teacher] I dare you to
tell him that. (chuckles) [student] I feel like half his muscles is steroids. What’s that, sir? – [Student] I feel like half his muscle is all steroids. – [Teacher] Maybe, maybe. – [Student] He got caught for steroids. – [Teacher] He did he did, he got kicked out of the UFC,
right, because of that? – [Student] He got suspended for a year, like, a year, six months. – [Teacher] Malcolm? – [Malcolm] When you use a cadaver, are you looking at advanced anatomy? – [Teacher] General advanced, yeah. Yeah, general advanced. If you guys wanna see ’em
towards the end of the semester, I’ll go take you guys in and show you. Okay? Yeah, I’ll totally do that for you guys. All right. So yeah, when you look at most wrestlers, most wrestlers are all doing ‘roids. – [Student] Oh yeah,
they’re all on ‘roids. All of ’em. Even, like, The Rock, and John Cena and stuff. I don’t think they– – [Teacher] They’ve all admitted it, yeah. – [Student] I think they’re
doing test for like HGH and stuff like that. They’re giving them some
sort of grow hormone. – [Teacher] Yeah, they’re all, they’re probably all doing
that to a certain degree. It’s almost impossible to get that big. I mean, you got body builders, pretty much every body builder is on it. You just can’t get that big without it. – [Student] Even the
natural guys, they arrive, until, like, three weeks
before the competition so it’s out of their systems so whenever they take the piss test or whatever test they take,
its still in there. – [Teacher] Yeah, I mean, I got a friend who does all natural body building, but he’s, like, in his 50s. So he’s, like, in the senior category. I mean, you know when the guys
are natural body builders, they’re muscular but they’re not huge. They look like muscular guys
with no body fat, right? A friend of mine, his cousin thought about
becoming a wrestler. So he was, like, he went and started
practicing with these guys. Man, he was so sore. And all these guys are,
like, laughing at him. He’s, like, “Why are you laughing?” Like, they all did ‘roids to recover. I mean, you can’t bash
somebody over the back with a metal chair,
(students chuckle) you know what I’m saying? Or throw somebody off the
top rope onto a folding table without getting hurt, really. I mean, seriously. So they all do ‘roids, every one. Even in the, like, the
ones we see around here in the bars over hunting season, you know? All those guys are on ‘roids. – [Student] You can usually tell because if you look at, like, their chest, a lot of them have
gyno, some sort of gyno, like a small case or (mumbles). – [Teacher] Yeah, usually,
you have gynomasty. But that’s usually
typically when they stop. It gets really bad when they stop. Any of you guys understand
what he’s talking about? All right, it’s like breast
development in the male. – [Student] Fatty tissue that builds up, like, underneath the pecs
so it looks like (mumbles). – [Student] Doesn’t it also cause, like, the hormones to do– – [Teacher] Oh absolutely, yeah. Yeah, you ever wanna know
if a guy’s on ‘roids, just look at his testes. Can’t find ’em, pretty much. They’re, like, raisins. – [Student] A couple
of people I talked to, they knew people that did steroids and they would have to get,
like, hormone injections, shots, stuff like that. – [Teacher] Yeah, yeah. If it’s medicinal
necessity, that’s one thing. But most guys aren’t in that way. All right. What were we talking about again? Oh yeah. (students chuckle)
Greater omentum. All right, let’s just talk a little bit about the oral cavity. We’ll go through the oral cavity and then we’ll take a break. We look at the oral cavity, we have the muscles around the face that are responsible for mastication. I’m gonna give you these muscles because we didn’t really
go through a lot of these in the muscular chapter. We have this one muscle
here called the masseter. The masseter is the main
muscle of mastication. So the masseter. Now, the masseter is the
one on the side of your jaw. When you watch somebody chew and kinda like the sides of their jaws kinda bulge out when they’re biting down, that’s what we call your masseter. Now, I like to call it mass-eater, right? The mass-eter. (mumbles) today? You betcha. So the mass-eater is the one
that helps us chew our food. Now, it’s very obvious in some dogs. You guys ever see a pit bull, or a bull dog, they have
these big muscular cheeks? That’s the masseter in
their jaw musculature. That’s the masseter, that big muscle that helps you bite down. Now, when we look at the oral cavity, this is where we see mastication. We chew up the food, we break it down, and then we allow chemical
digestion to take place. Now, we have these accessory organs, the teeth, the tongue
and the salivary glands. These are all accessory organs which help with mastication
or chemical digestion. The tongue, ounce for ounce, ounce for ounce, the tongue is the strongest
muscle in the body. Right now, the largest and
strongest muscle in the body is your gluteus maximus. Anybody know what that is? Your butt muscle? Okay, your mutt muscle is the
strongest muscle in the body. But it’s because it’s the biggest. If your tongue was as big as your butt, it would lick it every time. (fake laughs) Did you get that, right, take a licking? All right. So ounce for ounce this tongue is the strongest muscle in the body. Now, the tongue helps to taste. It’s responsible for taste. It helps you with chewing
and swallowing, as well. So taste, chewing or mastication, swallowing or deglutition, these are all functions of your tongue. Obviously your teeth are for mastication. Without your teeth you would not be able to grind up the food. My oldest son just
received braces this week. It was his birthday present. Just kidding.
(students chuckle) But he got braces on Wednesday and his teeth are really sore. How many of you guys had braces? Any of you guys have braces? Yeah? All right, is it typically normal for your teeth to be really sore so can’t, like, really
chew very well at first? How many days? Like, the first week? – [Student] I couldn’t eat
anything for the first week. It was, like applesauce
and Jell-O and ice cream. – [Teacher] Okay. – [Student] Lots of cold stuff. – [Teacher] Yeah, all right. (student speaks indistinctly) All right. And every time you got your band changed. That kinda hurts, too? Hurts a lot, too, yeah? – [Student] I always wanted braces. – [Teacher] You always wanted braces? (students chatter) Well, hey. (students laugh) Honestly, I would think
about getting braces at my age even, because my
teeth are shifting a lot, kinda stuff, it’s just
(vocalizes disgusted sound). I don’t think they do retainer any more. I don’t know, I’ll have to ask. They have like the invisible one. Oh yeah? I’ll have to see, see if it works out. All right. Teeth. Now, around your teeth we have this mucosa called the gingiva, that’s your gum. Your gums, your gingiva, your gums. Now, did you know your gingiva is extremely important to your health, even your heart? Do you guys know that, that your gingiva can affect your heart? You’re shaking your head Andrew can you tell us why? – [Student] I don’t know
why, all I know is leader of heart disease
was, like, gingivitis, or gingivitis caused heart disease. – [Teacher] Yeah, yeah. Any of you guys remember those
commercials that were on, I don’t know if they still run ’em? But every once in a while,
like, this dentist will show up and say, “You’re going a great job “taking care of your muscles,
but what about your heart?” And the guy’s, like, “Well yeah,
of course I’m doing that.” He’s, like, “No, you got cavities.” When you look at the gingiva, if you get gingivitis
or if you have cavities, that can lead to a very serious infection that can affect your heart
and cause heart disease. Now, in America it’s not
necessarily as common as other parts of the world. Other parts of the world,
60% of the population will be affected by that, where they have cavities
or problem with their mouth that lead to heart disease. In America not so much because we have all kinds of antibiotics
and stuff like that that’s very readily available, right? Just walk downstairs to the free clinic and get some antibiotics if you want to. So there’s a lot of that going on. Now, when we look at the teeth, we have 20 baby teeth. We have 20 deciduous or baby teeth. Alright; twenty deciduous or what we call baby teeth. Then we have 32 permanent or what we call adult teeth. So about 20 baby teeth and
those fall out, typically, and then your adult teeth come in. But this is a weird thing. When you look at teeth,
teeth are very weird. How many of you guys
still have baby teeth? Like, maybe some of your
premolars are still there? No, everybody’s got those out? I’ve had a number of students that have still had, like,
one or two of their baby teeth still left in there. Or how many of you guys have only, like, two of your wisdom teeth? Only two of ’em came in? (student speaks indistinctly) What’s that? None of yours came in, none at all, yeah? Well, that’s good ’cause you haven’t had to have ’em pulled out. – [Student] I only got
three of mine taken out. – [Teacher] So you still got one left, or it never came in? (student speaks indistinctly) It never really moved all that much, yeah? It’s kind of weird, right? I’ve had students that they’ve
had wisdom teeth taken out and then they’ve had a second set grow in. That’s wicked, that’s
just terrible, right? That’s torture. – [Student] Girl, and her front tooth, she had, like, an extra one– – [Teacher] Are you serious? Did she have to get it pulled out? Um-hm.
Ew, yeah. (student and teacher
speak over each other) – [Student] My younger brother had a tooth growing out of the roof of his mouth. It was just like an extra tooth and they had to go and remove it. – [Teacher] Yeah, that’s really weird. – [Student] My sister
had, like, her mom’s crazy. She has a tooth growing
on the side of the gums, but one over here, like,
a couple down here. – [Teacher] Oh, man. She’s like a shark. – [Student] Yeah, I know. – [Teacher] Just pull those suckers out and new ones come in. Wow, that’s gotta be painful, though. Yeah, kind of irritating, painful. But it’s weird, it’s just weird how the teeth just kind of … there’s this standard
but then there’s so many, it’s actually very common to have all these different anomalies. All right, so your teeth. The other accessory organs
are these salivary glands. We have three sets of salivary glands. We have these big parotid glands. There’s the parotid gland. Now, here is the masseter. So you see this muscle right here on the side of the face? This guy right there, that’s the masseter. Now we have these other salivary glands. We have this sublingual salivary gland just below your tongue. And then just below the mandible, we have these submandibular glands. So sublingual salivary glands, set of submandibular salivary gland. So these are the three
sets of salivary glands. Now, these guys are very important because they produce lots of saliva. Now, is it better to
produce lots of saliva or not much saliva? What do you think, Jess? [jess] Can you have too much problems if you have too much saliva? Not really. So obviously the answer is,
you wanna produce a lot. Lots of saliva is good because it helps to clean your mouth. Saliva cleanses the mouth and it prevents bacterial growth. That’s the reason right
there that research shows that dogs have cleaner
mouths than humans do. You guys have heard that before, right? Dogs have cleaner mouths than humans do. How could that be true? If you guys have a dog, you
know that dogs are not clean. They lick themselves, they eat poop. I mean, whatever it is, they’ll eat it. So how can they have
cleaner mouths than we do? It’s all about the saliva. They produce saliva constantly. And that saliva cleans their mouth of all the junk that they’re ingesting. Okay, so we talked
about these, taste buds. And then we have the
salivary glands, so saliva. Cleans the mouth, cleans your
palate, cleans your mouth. It helps to soften and compact
your food into a bolus. It begins chemical digestion. Now I’m gonna tell you the enzymes here. We have amylase, and that is for starch. Then we have one called lipase, and that is for fats. So we have these enzymes in saliva. We have enzymes. One’s for carbohydrates. We call that amylase. And then there’s one for
lipase, that one’s for fats. Now, the fun thing about amylase, because it’s for starch, what are forms of starch? Potatoes.
Potatoes. Pasta. White rice.
Rice. Yep, and? Bread.
Breads, okay? Now, if you guys wanna try this, it’s kind of interesting. If you take a cracker, the
more processed the better. So if it’s like a Saltine,
they work the best. You put a Saltine in your mouth and don’t masticate it, don’t chew it up. Just let it sit there. After about 90 seconds, if you can hold it there for 90 seconds, it’ll start tasting sweet. It’ll start tasting like sugar because carbohydrates
or starch are all what? It’s just basically sugar, right? And amylase breaks down the bread, it breaks down the cracker into glucose and you start to taste that
after about 90 seconds. That’s interesting. Have you guys ever done that? Have you done that before, yeah? All right. Try it over the weekend, right? Okay, so we produce about one and a half
liters of saliva a day. That’s a lot, right? One and a half liters of saliva. But again, like I said, it sounds gross but it cleans your mouth and it’s good. Now, teeth, we talked about the baby teeth and the adult teeth. Now, the tooth is covered with
a substance called enamel. Enamel is the second hardest substance that is naturally occurring. Some of us have a lot
of enamel on our teeth and some of us have not as much enamel. The more enamel, the harder your tooth and the less cavities you probably have. If you have soft enamel
or not as much enamel, you probably get cavities a lot. That’s just how much
enamel your body produces. But the funny thing is that
it’s the second hardest naturally occurring substance. What is the hardest naturally
occurring substance? What do you think? What do you think, Logan? – [Logan] Uh, it’s just a
guess, but is it diamonds? – [Teacher] It is, it is. Your teeth are second only to diamond. Isn’t that crazy? That’s pretty cool. Maybe we should put those on a ring. “Here, honey.” (students and teacher chuckle) What’s that? (student speaks indistinctly) So like their eye tooth, yeah? Oh, that’s kinda weird. But hey, it’s really hard. It’s never going anywhere, right? Just put it around a necklace. Like a shark tooth or a bear tooth or a lion’s tooth or some, you know, exciting, I don’t know. (student speaks indistinctly) As long as it’s not
your baby teeth, right? Make a necklace of your baby teeth? (teacher and students laugh) That’s gross. Okay. (students giggle) All right, why don’t we take a break and then we’ll finish up
here the second lecture.

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