 Hey everybody, Dr. O. In this video, we're going to talk about the endocrine portion of the pancreas. We will cover the majority of the pancreas and its exocrine functions, like the production of digestive enzymes and its location and all that. We'll talk about that when we get to the digestive system, sorry. So we're just going to focus on one part of the pancreas. About 1% of the pancreas is these islets, which means islands, the pancreatic islets. Or when I was in school, they were called the islets of longerhonds. You still might hear that. So 1% of the pancreas is going to be these small islands that produce endocrine, that are endocrine glands that produce hormones. So let's go ahead and I'll show you, I have the list here. So we have their alpha cells, beta cells is the only two we care about, but then there are delta cells and PP cells, so don't worry about them. But out in another way, how I remember this, kind of like I did with the gonadotropins, A comes before B, alpha before beta, G, glucagon comes before I, insulin. So alpha cells produce glucagon, beta cells produce insulin. So from a percentage standpoint, insulin is about 75% of the hormones produced by these pancreatic islets, glucagon would be about 20% and the other 5% would be the other two, the somatostatin and the pancreatic polypeptide cells, but we won't worry about them. So insulin versus glucagon. Another way, just remember, insulin, I'll put it on the screen, insulin, glucagon, right? Insulin is an anabolic storage hormone. Yes, it does reduce blood glucose levels, but it does so by telling your cells to take up glucose, telling your cells to use glucose for fuel, telling your cells to stop using fat for fuel, using glucose to fuel the absorption and use of amino acids to build protein. So it isn't just about lowering your blood sugar levels, it's a storage hormone. Anabolic storage hormone is the best way to describe it. So it tells your body to hold on to fat and not use it, so you can use glucose, it tells your body to build muscle, take glucose into your cells, store glucose as glycogen. So remember, glycogen is how your body stores glucose. It can store it in the liver, and that's used to regulate blood sugar levels, and it can store glycogen in the muscles, and that's used to fuel muscle cells. So insulin's job is to store, which is why you see high insulin levels after a meal. Glucagon, so when your blood glucose is gone, you're going to need glucagon to prop it back up. So glucagon's job is to raise your blood sugar levels. It would tell your body to break down glycogen, especially at the liver, and use that for fuel. So it would tell your body to use fat, et cetera, et cetera. So yes, the simplest way to look at it is insulin lowers your blood sugar, and glucagon raises it, but it's much more complicated with that, especially with insulin. Insulin plays huge roles in other hormones as well. I think that's plenty about insulin though, and then glucagon. Let's see how they work here. So here we see the feedback systems involved, so let's kind of walk through this. We'll start with hyperglycemia at the top there. So if someone has high blood glucose, you see there it says, what, 160 milligrams per deciliter? That's very high. This was fasting. This person would be diabetic. So fasting blood glucose above 125 would be diabetic. So if this is post-prandial or after a meal, then I guess that'd be somewhat normal, kind of high, but somewhat normal. So after a meal, blood glucose goes to 160. Your body will respond by releasing insulin. Insulin will, let's look at what it does, insulin is going to tell your cells to take up glucose. It's actually going to stimulate the glucose receptors like Glute 4 to absorb glucose and take it in and use it. So your body's going to use up some of that glucose. It's going to tell your liver to stop breaking down glycogen and making more glucose. We already have plenty. And it's also going to, so it's going to inhibit the production of non-carbohydrates, turning non-carbohydrates into carbohydrates, which is called gluconeogenesis. So your body's saying, don't make or release any more glucose. Let's use what we already have. That makes sense. It's going to bring your, you're going to use that glucose and not use fat. So that's going to bring that blood glucose back down and hopefully be back at normal. So that's how your body would use insulin to respond to high blood sugar, low blood sugar, hypoglycemia. So here we see it says 50. This is going to cause the release of glucagon. So glucagon is going to do the opposite. So the alpha cells, the pancreas release glucagon. It's going to tell your body, inhibit your body from taking up glucose. It's going to say, burn fat, burn ketones, burn something else. We got to keep this glucose in our bloodstream. It's going to stimulate the liver, glycogenolysis, yeah, the tearing apart and breaking down of glycogen, which will release glucose. And it's also going to stimulate gluconeogenesis, the creation of new glucose. So that's where your body turns non-carbohydrates like proteins into sugar. And that's going to bring your blood sugar back up. So that's how these two hormones will be used to maintain homeostasis. Now both of these can lead to disease states. We won't talk about hypoglycemia much here, but there are, there's hypoglycemia that occurs just when you're fasting. For some reason, your body just produces too much insulin and your blood sugar can plummet and that can be very dangerous. There's also reactive hypoglycemia, where after you eat a big meal, you get a spike in glucose, which causes too much insulin to be released and you see a drop of plummet and it goes too low. So that person, which should eat a diet that keeps their blood sugar more stable. But let's talk about hyperglycemia. So that we have, we have two major types of diabetes we can talk about gestational as well. Type one and type two. So type one diabetes is an autoimmune disease that destroys the cells of the pancreas that produce insulin. So this person needs insulin because their pancreas doesn't make it type. That's going to be actually less than 5% of all cases of diabetes. Almost everyone that's diabetic has a type two. Type two diabetes is going to be insulin resistance. The pancreas is churning out plenty of insulin, but your cells have down regulated like we talked about before and they've become resistant and they're not listening to the message. So it takes more and more insulin to get your cells to take up and use glucose. And this is type two diabetes. Now that can get so bad that someone does end up requiring insulin at some point. So we'll cover type one and type two diabetes kind of more specifically later. There is gestational diabetes, which is diabetes that you develop during pregnancy. And I think that those are all, those are all the main ones there. So we also talked about hypoglycemia. So maintaining your blood sugar is very, very important and obviously diet and exercise lots of things are going to have an impact on it. We're just talking about the role of the hormones here today. All right. So that is the exocrine or sorry, the endocrine portion of your pancreas that makes insulin and glucagon. I hope this helps. Have a wonderful day. Be blessed.