 Do you remember the function of the pancreas? Remember the pancreas was that it looks just like this. And it had the pancreatic duct that emptied into the duodenal papilla. So this is the duodenum. Yeah, and there's my duodenal papilla. And also coming in is the common bile duct. We're all over this action. Because the pancreas has exocrine tissue and endocrine tissue, there are two different structures that we're going to see in here. For one thing, we're going to see these kind of round islands. They're going to look different than the tissue surrounding them. Depending on the stain, they might look super different or they might look kind of similar but slightly different. They have cells and these are called islets of Langerhans or pancreatic islets, pancreatic islets. They're like little islands in the pancreas. And these guys are your endocrine structures and they produce insulin and they also produce glucagon but both of those hormones are involved in glucose homeostasis. The surrounding, the pancreatic islets, are a billion glandular structures. And these guys, and I'm drawing them like this, it's not a single cell, it's actually, it's a gland. It looks really similar to all the other glandular tissue that we've been looking at so far but I really should have drawn them all like this because these look like individual cells and I am not going to draw them all but that's what they are. These guys are called ascini and they're producing the exocrine secretions which are bicarbonate ions to neutralize the stomach acid, digestive enzymes to help digest proteins and carbohydrates. And I don't know, do they make fat, digest or fat enzymes too? I'm not, I don't think so. I think the bile emulsifies the fat and then we just absorb it directly. So all of this stuff produced by the exocrine structures that the ascini is dumped into the duodenum. Most of the pancreas, I think the number, it's like in the 95% of all pancreatic cells, can't remember the exact number, are exocrine cells and a very small number of them are actually endocrine cells found in the pancreatic islets. I expect you to be able to identify the islets, to identify the structure, looking through the microscope, to know I'm looking at pancreas and to know what comes out of each of them. So endocrine secretions coming out of the pancreatic islets are going to be insulin, glucagon, hormones. They go into the blood. So you also are going to have to have blood. Here's a little blood supply. Look, I'm going to draw it like this. Do my exocrine structures dump, fluid into the blood? No, they dump it outside your body to the lumen of the duodenum, because it's exocrine. That's the definition of an exocrine structure. Endocrine structures dump into the blood. That's the definition of the endocrine structure. Done. Digestive histology. You guys are rock stars, and so am I. Now I'm going to go move around dead bodies.