 Well, hello there. Today, we're going to talk about the histology of the digestive system. Last time, we looked at all of our tubes, and we looked at the fact that, dude, your digestive system is one giant tube that runs through the middle of your body like a donut hole. And now, we're going to slice the tube into little pieces and little cross sections so that we can see the lumen of our tubes. And then, we're going to name the parts and identify which part of the tube we're in based on what the histology looks like in that part of the tube. For perspective, I have here histology. Oh, I'm going to try to avoid actually looking at actual slides in this lecture. But check this thing out. You can see that it is, in fact, you see my tube here. Do you agree with that? Look at my lumen of my tube. Look at this squished up little lumen. Do you see it? How cool is that? It just got smashed and smushed, but that's the lumen right there. Do you agree with that? So this is just a cross section of a tube. Now, what is something that you notice about this tube? Do you notice that it looks like we've got layers? We have layers. And every single part of your digestive tubing, if we slice it, has almost the same exact layers in it. So look, there's this layer. Do you see how, do you see even what I just did? I meant to make that a different color. But do you see like outlined in black? Doesn't that look like one layer? Again, watch the magic. Check it out. Doesn't this look like a different layer? What would you say? Like, what's different about it? We're talking about histology, dog pounds. We have a different kind of tissue here, but you can see that, okay, yeah, we've got something that looks a little, something like this close to the lumen of my tube. And then the tissue changes. If the tissue changes, if the structure changes, what do we know will also change? The function is probably different. Do you see another layer? Oh, you know you do. In fact, I'm just going to go like that. This is another layer. Do you see how, I mean, you could argue that we have three different layers in my tube. And since I'm arguing that and I'm the teacher, yeah, it's totally three layers. There's all this other stuff around the outside edges, all of this goop. Is it a mess? Is it, like, what is that? Does your digestive tube live in a vacuum? No, it lives in you. Is there any tissue outside of the tube? Yeah, follow your esophagus down your body. Like, if we go out from the esophagus, if we go basolaterally through the esophagus, we're going to run into all different kinds of tissues. We're going to run into all different kinds of structures. And as we move out, there's lots of other stuff going on. That's what this all is out here. That's all your other stuff that's happening. So we're going to name the layers of our tube. We're going to look at how they all are. And then we're going to look at each part of the digestive system and then we're going to look at how the histology is different in the different parts and how that actually we could probably guess how the histology is different because the structure determines the function. I'll be right back.