after the stomach, the food or as we should call it now the Kym will enter the small intestine through the pile oryx sphincter, the small intestines long tube in which digestion is going to occur. And also this is very important absorption. This is where you get to finally get the payoff for this and absorb those nutrients and the small intestine are actually are. The small intestine is actually going to be assisted by the pancreas and liver. Who are going to provide some nice secretions that will help with the digestive process. Now, small intestine is often a often leads to some misconceptions because it's actually longer than large intestine. It just has a smaller diameter, and in fact it's really long. It's like 6 m long, which, you know if you think that a meter is like approximately, like a little more than 3 ft, you know, talking about 20 you know, roughly 20 ft here. Obviously, humans aren't 20 ft long, and that's because our small intestine are all wrapped up. Thio minimize the amount of space they take up, but because they're super long, they have a lot of surface area on the surface area is actually even longer. Uh, due to some cool modifications that the small intestine has now first, if we look at the small intestine here, you can see that the tissue on the inside of the intestine has these folds in it, right? That's what these little lines are. Basically, the tissue itself is, you know, uh, made to fold to increase the amount of surface area on the inside of the small intestine. Now, this fold, if you zoom in, is actually covered in what are called Vialli. So basically, this fold has all these little projections on it. Thies, Vialli and these V Liar and turned in turn covered in what are called Micro Valli. So the veal I are gonna the cells of the veal. I rather the terror sites have these little hair like structures on their tips called Micro Vialli. This is going thio result in a crazy amount of surface area. Right? We have the tissue itself folded, those folds air covered in Vialli and those Vialli are covered in microbes. Eli. So we are maximizing surface area here now. Veal. I actually a surround blood vessels. As you can see in this image here, and they also have what's called a lacked hell in them And this structure here. Okay, it's lacked hell, and basically, it's a lymphatic vessel. The lymphatic system is going to be a system involved in both circulation and immune functions, and we'll talk about it at a different time. Just know that it has, uh, projections into these ville I, as do blood vessels. Now, the do wadding, um, is what we call the start of the small intestine. That's where the Kym is gonna enter, and the duodenum secretes hormones in response to the time. Uh, two of these hormones are SEC written, which is a hormone that's going to stimulate bicarbonate release from the pancreas. And that's super important. Because, remember, the kym is filled with acid, and you don't want all that acid sitting in your poor small intestine. So they're going to ask for some bicarbonate from the pancreas to help neutralize the acid. The other hormone is, ah, Cola Cola site or Kainan. It's a mouthful. CCK. That's that's what they call it in med school and stuff that's whatever it calls. It's a lot easier. So si ck is going to be the hormone that stimulates the pancreas to secrete digestive enzymes. See, not only does the pancreas provide nice bicarbonate solution for the time Thio cool off, so to speak, it's also going to secrete a bunch of enzymes that digest the food, uh, coming from the stomach. Now, these include things like nuclear bases, which breakdown nucleic acids. Uh, pancreatic amylase, which, similar to salivary amylase, is going to break down carbohydrates into maltose indexed Reines, as well as pancreatic light paces that break. Try celeb Lyssarides into two fatty acids and a mono a soulless a ride. Now, pancreas will also secrete Prodi aces and two of the important ones to take note of our trips in and Kimo trips in. And these air Proteus, is that break down proteins into smaller poly peptides. It should be noted that they actually will Onley break specific poly peptide bonds. That is Polly Pep. Uh, that is peptide bonds between specific types of amino acids. So just like other enzymes, they are very specific as to what they will act on. What's cool about these is there actually also Zim Mogens like Pep Synergen. So they're released his trip Synergen and Kima trips engine. And this enzyme called in Terra Cockiness, which is produced by the small intestine, is what will activate trip Synergen. And that leads to the activation of other Prodi aces, which will help break down those poly peptides. Now with that, let's flip the page.