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Raja Narayan 创建




all right and then on that note why don't we move on to the next part of the pancreas which is known as the endocrine pancreas and this is actually the part of the pancreas that is the most famous we hear the most about this as we'll see in a minute because it has a lot to do with diabetes the endocrine pancreas will release hormones rather than the salts or enzymes we saw above will release hormones that go into the bloodstream and they will move on elsewhere throughout the body to the liver perhaps the intestine or even as far as muscles to cause things to happen and the way the endocrine pancreas is organized is that there are many eyes lit cells it's actually pronounced islets but I'm mispronouncing it just to let you know how it's spelled eyes lit or islet cells that exist and sit in Islands sit in Islands so there are three types or three main types of islet cells we're going to talk about and they're all present to some extent in each Island or group of cells in the pancreas and let's go through them one by one so first of all we've got what are called alpha islet cells alpha islet cells and these guys release a hormone that's called glucagon glucagon and the main function of glucagon is to take things like glycogen which is a whole bunch of glucose molecules that are stacked up on top of each other and then break them down into smaller glucose monomers or molecules so we're making glucose from glycogen whenever we release our glucagon so I'll write glucagon up here and it's not just carbohydrates but glucagon is responsible for the breakdown of a whole bunch of macromolecules so I'll just drive it home by writing glucagon causes breakdown over here the next type of islet cell that we have and perhaps the most famous of them all our our beta islet cells so our beta islet cells house and release insulin now when you hear insulin there should be a lot of light bulbs coming up because insulin is responsible for a whole bunch of things for one when we look over here insulin is what causes the opposite of this reaction where instead of breaking down glycogen into glucose insulin causes glucose to be stored or built up into glycogen so insulin does the exact opposite and again to drive that home it's not just for carbohydrates but it's a whole bunch of things that get built up so all right insulin is responsible for the build up or storage of our macromolecules but what might be the most important thing to mention about insulin is that it is the hormone that is related to or responsible for the disease known as diabetes and gosh we can have entire tutorials on diabetes and what it does and what it means but for right now just know it it's bare basics diabetes occurs or causes damage to our bodies because we have too much glucose too much glucose floating around in our body too much sugar all right and that happens because insulin is not working properly we're not building up and storing glucose in a glycogen like we're supposed to be doing instead it's running all over the body and because of that we have what's called eye nerve and kidney disease that's sort of the catchphrase we use in medicine to describe diabetes it's AI nerve and kidney disease because with too much glucose over time weren't able to see the nerves most commonly in our feet are not able to sense pricks or things or damage that occurs there and eventually they could cause amputation and our kidneys stopped working overtime which could lead to dialysis and that causes early death and in addition to these three glucose goes all over the body and causes a whole bunch of other things like earlier onset heart attack and other types of complications the other thing I should mention about diabetes is that there are two types of diabetes there are two types there is type one diabetes and there is type two and the way you differentiate type 1 versus type 2 diabetes is based on how it's caused and this all points back to insulin in type 1 diabetes we have no insulin so the person that has type 1 diabetes has no insulin production and because of that we're not able to store our sugar in glycogen we're not able to put it away and so we have it all over the place that causes high nerve and kidney disease among other complications in type 2 diabetes your insulin receptors so you have insulin that's being produced but your insulin receptors are broken your insulin receptors are broken so even if we do produce insulin and it goes to where it's supposed to go in our body these receptors will not respond and so it's as if we don't have insulin in our body at all and there's so much more that we can say here but we'll close our conversation on diabetes for now and we'll revisit this later let's move on to the third type of islet cell that we've got in the pancreas and those are Delta islet cells Delta islet cells and these are the guys that release a hormone called somet oh so Matt OH statin so Mattos statin which is a major party pooping hormone released from the endocrine pancreas because it's main job is to stop the jobs of all the other hormones that are active and these hormones can include things like what we've talked about here glucagon insulin but there are other hormones that are also in play in the GI tract that include things like cholecystokinin that we talked about elsewhere and so NAT a statin will go in and cause the effects of those hormones to stop and that's sort of its main role there so that's our endocrine pancreas and as we talked about earlier our exocrine pancreas so the pancreas is responsible for a lot no wonder surgeons have the phrase eat when you can sleep when you can and don't mess with the pancreas