 All right, let's look at the anatomy of the oral cavity. First of all, we should probably define the oral cavity, and we'll do that in a second. But in the oral cavity, you are going to have both mechanical and chemical digestion taking place. So mechanical and chemical. And the mechanical digestion happens because of whom? The teeth. Chemical digestion happens because of whom? Saliva. So there are actually digestive enzymes, digestive chemicals in your saliva that begin chemically breaking down your food in your mouth. So if you took a bunch of food and smashed it up so that there was a lot of surface area, added some fluid to it and then spit in it, you could actually witness your digestive enzymes in action. In fact, I made my online general bio students make cornstarch pudding and then spit in it. And they totally found that the saliva made the cornstarch pudding super watery because there's salivary amylase that breaks down the cornstarch bonds. So you can try that out at home if you want to. Spit in your pudding and you'll be amazed at the outcome. So let's look at what is this oral cavity because you would think, dude, oral cavity, how hard can that be? But of course, it's anatomy and so there are some distinguishing characteristics here, defining characteristics that we probably should take the time to define. So oral cavity is inferior to both the hard and soft palates in your face. So think about it. Feel the roof of your mouth and you can feel that that's a bone and it's actually a bone that we will know and name when we do the skull. But that bone is your hard palate and I'm just going to color it in here in yellow. This is my hard palate and I'm going to color in green because it is posterior to the hard palate and culminates in the uvula. That's your soft palate. Now the soft palate, the uvula is that little wormy thing in the back of your throat. I don't know if you can see mine. You totally can see it. I had a student once who had a forked uvula. It was super cool to look at. So the uvula is like just the extension or the end of the soft palate. So feel back up in there again and you can feel where the hard palate ends and where the soft palate begins and it's squishy and then I guess if you're awesome you could feel your uvula. But if I tried to feel my uvula I would definitely vomit in front of all of you and friendship only goes so far. I'm not going to do that. All right, ready? Because why are we talking about vomiting uvulas? Because inferior to the hard and soft palates is the oral cavity. Now, if you check this out, this is a space. That's my oral cavity. Oh, good lord. That says oral cavity in a very light color. Now, I just have to outline this thing because this is marking the inferior border. What is that giant thing? Dude, yes it is the tongue. What? I mean, seriously, that's huge. Do you really feel like my tongue is that big? Look how dainty and tiny my tongue is. But if you cut my head in half and looked at it like my tongue would take up a massive amount of space in my oral cavity. So my oral cavity becomes the space becomes kind of small because it's crowded by the tongue. In the oral cavity, let's see, we might have to come back to this drawing to see some of our structures, but let's go back to this guy and let's do some anatomy of, let's do the teeth first, the guys who are responsible for mechanical digestion. So there are four flavors of teeth in your mouth and I'm going to color code these puppies and they're the same on the top and the bottom. So you actually have, and I'm going to give you numbers for half of your face on top or on bottom. So on half your face on the top, you have two incisors. How many total incisors do you have? Well, you have two in one quarter of your mouth. So two, four, six, eight. You actually have eight total incisors, but when I say two, it's because we're just talking about one quarter. These guys are your incisors on the bottom as well. Now the incisors are teeth responsible for like cutting and slicing your food, whether it be vegetable or animal. You also have, let's see, we'll do this color, one canine. Canines tend to be pointy. They don't look super pointy in this picture. Everybody's canines are different. Some people's canines are super pointy and they're for puncturing and piercing and like slashing and piercing things. How many total canines do you have? You have four. You also have two, four, six, eight premolars. And interestingly, those premolars are baby molars. I don't know if that makes sense. When you are a little slime, you actually have like your baby teeth come in and the premolars that come in when you're a baby are considered baby molars. And then when they fall out, they grow back as these premolars. And then kids get their molars and there's actually three molars on a side, top and bottom. And one of those molars is the wisdom. One, four of them are wisdom teeth. And wisdom teeth are molars that often don't even fit in your face. And if they don't fit, then you actually have those wisdom teeth pulled. Feeling good about that, right? So those guys, your chompers, your premolars and your molars are responsible for grinding up your food. They're a little bit flatter. They have more roots to anchor themselves into your jaws, bones, into your mandible and your mandible and your maxilla. Again, we'll do those when we talk about the skull. But they're mechanically breaking stuff up. Let's look at our salivary glands. Now, there's a couple more structures that are labeled here in this diagram. But salivary glands, and I think I've got an image over here of salivary glands, but you actually have three sets of salivary glands. Three pairs of salivary glands. Now think about this a second. What kind of glands are salivary glands? You're treating substances into your mouth, which is outside of the body, so they're hexacrine glands. And these hexacrine glands come in pairs. So you have the parotid gland. And the parotid gland, para, means near. And ought means ear. So the parotid glands are actually in the front of the ear. It's the biggest salivary gland in your body, but it only produces about 30% of all of your saliva. The submandibular glands produce most of your saliva. They actually produce about 65% of all of the saliva. And the submaxillary, no, sublingual. I think submaxillary is fair game, but sublingual makes more sense. They're beneath the tongue, and they actually are. And they're just little weenie guys. They only produce about 5% of your saliva. So the parotid gland actually has a duct that you can feel on the inside of your cheek. So you can stick your tongue up there. It's in the upper between your cheek. It's embedded on the inner layer of your mucous membrane. It's a little bump. And if you kind of squiggle it with your tongue, you can actually feel the saliva coming out of it. And there's a duct between that and the gland itself. So if I were to draw this duct, I mean this is terrible because I can't really get up in there, but somewhere up in your cheek by your teeth, cool? Submandibular, this gland, let's see, let's do it. Oh, gosh, what color should it be? Submandibular gland has two, two ducts, one duct per gland. And the ducts are found underneath the tongue on either side of the lingual frenulum, lingual frenulum. And the lingual frenulum is this thing. So take a look at under my tongue. See that thing? It looks like a line. And you can feel it, like feel it on yourself. It's like a piece of tissue that attaches to your tongue and sort of keeps your tongue from flipping back into the back of your throat. Super handy, don't let that happen. So lingual frenulum is down the midline of your tongue and on either side of that thing are two little ducts from your submandibular glands. Now, those ducts actually allow a lot of saliva through. In fact, if you have any skills at all as a gleeker, which I do, oh yeah. And I just practiced because I was like, dude, I don't know when the last time was that I gleeked. I got to know if I can still do this incredible feat and I totally can. You can actually pull back, like flex your, like retract your tongue like this and then you can like squish your tongue forward and you can contract something that squeezes your submandibular glands and squirts saliva out of your ducts. And those are the glands that produce the most saliva. So it makes sense that you would sort of leverage those guys. The sublingual glands are beneath your tongue, but they have many, many, many, many ducts. So check these guys out. So submandibular glands are actually farther back. They're posterior to the sublingual glands, which are truly underneath your tongue. And I'll show you the glands in just a second, but I want you to be aware of where the ducts are because it's a little counterintuitive. So let's look at those glands. Indeed. Check it out. This is, oh, hello. This one is, what do you think? Sublingual? There's my tongue. Or submandibular? Did I just totally tell you? This is sublingual. And this guy is submandibular. And who's this? My friendly parotid. Notice the parotid duct. Notice, I'm going to draw the submandibular duct. Remember, this is the one. This is the gleeker. Here's the duct. And you'll notice that it has that one opening in the, like below the tongue. Check out my friend, the sublingual gland. Look at all these ducts that come out of the sublingual gland and line all the space next to your tongue. So there you go. Some salivary glands. What else do we need to do? There's a couple of anatomical structures that I was sort of going to label for you. If this is the lingual frenulum, what do you think this guy is? Sure, here. You can see it, that little line. It's another frenulum. It's not a lingual, lingual tongue. It's a labial, labial lip. It's your lip frenulum. Labial frenulum. And you'll notice that you have a labial frenulum, a superior labial frenulum, and an inferior labial frenulum. You also have ginger v. Actually, I don't know how to pronounce that. Ginger v. Basically, those are your gums. Your teeth are like held into your mandible. Your ginger v. Surround your gums, surround your teeth, that little joint, and protect that joint. Let's see what else. I don't think there's anything. Let's see. There's a space. A space. Of course, we must name spaces. The space right here is called your vestibule, and it's this space in here. And, dude, the only way that I can remember my vestibule is because I will never stick chew in my vestibule. I'll never put tobacco. What is it? Is it just called chew? I feel like it has another name. Chewing tobacco. I've never put chewing tobacco in my vestibule, but people who chew tobacco stick it in their vestibule. And then they spit in bottles and stuff, and then there's chewing tobacco spit all over the place. But it's your vestibule that you stuck it in. There's lots of vestibules in the body. Your nostril is a vestibule. The opening to your vagina is a vestibule. Don't stick chew in any one of your vestibules. All right. I think that's everything we need to know about the oral cavity. Let's talk about pharynxes. Pharynxes are very interesting.