 All right, home kids, we have a problem. We have a problem. The problem is you have 30 whatever feet of tube that we just built. We just went through, like truly we went through and like blew up this tube what started as this awesome cute little, oh, look, it's a mouth. It's like a penis, ha ha, little tube. And then we blew it up to be 30 feet long or whatever it is. Like I don't even care. It fits, it's long. Seriously, like 20 feet, 30 feet, 25 feet, 27, who cares? It's this huge chunk of tube that is crammed into your cavities. This, I guess, is like pretty straight shot through the mediastinum. But once you get into the abdominal and peritoneal cavities, like holy crap, dude, you are like twisting and turning and cramming and like, whoa. And here's the problem. What was the tube made out of? Cells, right? In fact, we drew some of them at some point. I don't remember when we drew this. It's been a long morning. But we talked about the fact that the tube is lined with a mucus membrane. So we have an epithelial layer and then we have connective tissue that's deep to this. So we actually have, do you remember the name of the connective tissue layer? The laminopropria. I'm telling you right now that there are other layers. Are there any cells in the laminopropria layer? Totally. And so are there any cells in the epithelial layer? Totally. There's cells in all of this. And the whole reason why we did this, the whole reason why we set this whole structure up is so that we could absorb nutrients and get it into what? Where are we going to put all those nutrients? We better get it to the blood and then send it to the heart so that the heart can pump the nutrients throughout the body. If you left the nutrients either in these epithelial cells or in the connective tissue cells, the rest of your body will starve. So this whole thing is totally pointless unless we have a blood supply to pick up the nutrients. Now, I don't know if I've even told you the problem yet. If you have 30 feet of tubing that is made of cells that need a blood supply, what's going to happen when you add 30 feet? What's going to happen when you add blood tubing to take care of 30 feet of cells? What's going to happen in there? Dude, I seriously, I don't even want to think about it. It makes me have a little bit of anxiety to think of the mess that that would be and guaranteed death. Why? Holy Tangle, you are going to pitch off your blood supply. If this is not taken care of carefully, you're going to have a tangled mess that will result in death. So your body came up with a solution. Are you ready for what it is? Well, the hint is right here, the title of this section. The solution to this problem is a mesentary and you might be like, dude, what the heck is a mesentary? And I will tell you that the mesentary is a double layer, a double layer of visceral, ah, peritoneum, and it's relevant because I want to remind you about the abdominal cavity. And please forgive this drawing. It is totally not accurate. And to try and make it accurate makes me also have anxiety. Remember that the serous peritoneum has a parietal layer that is lining the cavity itself. And then it folds in on itself, right? Okay, no, undo that. It folds in on itself and then the visceral layer surrounds some kind of organ. Do you see anything interesting here? So here's an organ. This is a tube, you guys. Now, highly simplified, totally inaccurate because this is one tube inside one box and we actually have 30 feet of tubes that are shoved inside here. But this is my peritoneal cavity, the PC, and guess what this thing is right here? A double layer of visceral peritoneum. Do you see that? This is a mesentary. Now, think about this for a minute. If, totally anatomically incorrect, if the heart was here and could send a blood supply through a mesentary, you keep a nice little sandwich that has all the blood tubes organized. And the fact is that organs in the peritoneal cavity are fed by blood that is sandwiched in mesentaries. There are three main mesentaries that we're going to know and I can't draw you the picture and I can't find an open and free image that will work for me. So we're going to get to look at them, look at the mesentaries in the cadavers and they're super clear. And if you remember the problem that the mesentaries are solving, it becomes elegant. It's really cool what a mesentary looks like. So the three that we're going to know, there's one called the greater momentum and it hangs down off the transverse colon. And again, what is it? It's sandwiching vessels and nerves for communication to the transverse colon. There's a lesser momentum. It hangs off of the lesser curvature of the stomach. Guess what the greater momentum hangs off of? The greater curvature of the stomach and connects to the transverse colon, the lesser momentum hangs off the lesser curvature of the stomach and connects to the liver. The lesser momentum sandwiches the vessels that travel to the liver bringing all the blood from the, oh my gosh, from all the digestive tubing to the liver. Remember I told you that everything that gets absorbed goes through the liver before it goes into the rest of your body. And the other one is mesentary proper. And mesentary proper is really pretty. It's actually like this fan of mesentary that connects all of our small intestines. Not all of them, but a lot of them. And when you look at it, and I know, you know, we've seen the cadavers already, so I know that it's a structure that's kind of interesting in the digestive scene where the tube is on the edge of this fan-like thing. It's like a ruffle on the edge of a skirt. And the fan is the mesentary containing all the blood vessels and nerves that go to that outer small intestine tube. So, mesentaries, super important. Actually pretty easy to identify. And boom, you just knocked out lecture number four. And you, yes, you did. I knocked out lecture number four. That one was not easy to get out. Okay, digestive histonext, steady hard.