The Pancreas, Liver, and Duodenum Work Together

hello this video is about how the pancreas the liver and the duodenum work together pancreas liver and duodenum work together oops work together and the purpose of them working together is for chemical digestion and then modification or transport of nutrients so let's get started looking at this alright so this right here this part right here is the duodenum this is the first curve of the small intestine so the stomach is kind of up here over this way not shown on this picture and let's just go ahead and highlight this the wad numb in with an orange highlighter like this and it gets its name historically because it means like twelve fingers doooo dhinam and in fact that's how a lot of people pronounce it as duodenum but I think more people saved wat them so it literally means twelve fingers because that's as long as it was it was like twelve fingers long so ten of fingers and then two more is about the length of it and you can see that it curves like this and has a cozy relationship with the pancreas so let's use a blue highlighter to put the pancreas on here right like this and the pancreas is super squishy it is almost all made of epithelial tissue rips kind of easily I think of it as like cottage cheese E and structure so in blue here this is the pancreas and this structure right here is the pancreatic duct so all of the stuff that the pancreas is making can go down into the duodenum so this is where the stuff that it makes enters the duodenum down this duct and what is it making well first of all the pancreas is making bicarbonate this is basically like baking soda and just like that it is meant to make the chyme that's coming from the structure of the stomach more basic so it's job is to neutralize acidic chyme after food leaves the stomach or when it reaches in the stomach the chyme Reach is a pH of 2 which is very very low pH and so when that kind comes into the duodenum if it didn't get neutralized the duodenum can't protect itself as easily from acid as stomach can and so the acid would literally rip up the duodenum and cause duodenal ulcers and some people do struggle with that problem but under in a healthy situation then the bicarbonate will neutralize the acidic chyme from 2 all the way up to a more basic pH of 8 so this prevents ulcers but it also has another really cool and really exciting function in the stomach we talked about how pepsinogen is not activated until it's a round acid and then it's able to start breaking down proteins well the duodenum enzymes work the other way they can only be active at a neutral pH so this bicarbonate acts to activate the pancreatic enzymes and those enzymes generally fall into this category amylase or similar types than those break down carbohydrates down into sugars lipase breaks down lipids or fats down into fatty acids and glycerol and then there's a whole bunch of different kind of proteases that break down different combinations of amino acids so that long protein can be broken down into its component amino acids now all of these are considered exocrine products because they're secreted onto a mucous membrane or onto a membrane so they come out here and they're secreted here the pancreas also makes insulin that goes into the bloodstream so it's considered an endocrine product it's a hormone so let's put that next so we've got the bicarbonate we've got pancreatic enzymes another thing that's coming out and then in a whole different category because it's not going into the duodenum at all but insulin and glucagon too but we don't talk about that one as much insulin will be secreted into the blood so this is considered an endocrine product because it's a hormone and it's going into the blood so for that reason the pancreas is actually an endocrine and an exocrine gland and it makes sense the insulin would be secreted though at the same time that a meal containing carbohydrates enters the duodenum because all of these simple sugars are going to go into the bloodstream and they're gonna raise blood sugar and what is the job of insulin well it's going to lower blood sugar so sometimes I call well most of the time I call insulin a storage hormone for that reason okay yeah this is a fun page of notes so now let's go back up here and kind of remember what what were we doing looking at the pancreas and its role in helping food be broken down so these enzymes come into the duodenum and in this area right here about 80% of the chemical digestion occurs and a bunch of absorption actually occurs too even though the small intestine is very long most of the work it's done in the first couple of feet of it so now we also have to think about the action of lipase lipase breaks down fat but it can't do it until the fat has been broken up into droplets so now let's get a green highlighter and color the gallbladder green believe it or not the gallbladder actually is green oh I remember something else I'd wanted to tell you when we were talking over here about bicarbonate coming out of the pancreas so if you have a bunch of bicarbonate in here and then a person has chronic diarrhea diarrhea diarrhea diarrhea they lose a lot of bicarbonate from their body and the body can actually become too acidic and so for that reason someone's blood can become too acidic if they've had chronic diarrhea for a while it can be a problem in like for example cholera and other really bad diarrheal diseases okay so this is the gallbladder and we'll write that in green and it has two jobs it stores the bile but it also concentrates it notice it doesn't make it it stores it and it concentrates it and if it concentrates it too much guess what you get gall stones so the bile is actually produced by the liver and this is the liver right here so the liver produces the bile and then file goes down the hepatic duct right here I'm gonna use the yellow highlighter on that the paddock means liver so this is the hepatic duct the bile comes down the hepatic duct and if if you're right in the middle of a meal it can just continue right on down the bile duct and go into the duodenum but if you're in between meals or it's more bile than is needed for that meal then what can happen is that the bile can actually be pushed back up in beat to be stored in the gallbladder and that this structure right here is the cystic duct and that word Siskinds to the ball like structure of the gallbladder so to go over this again we have three different duct names you have to learn the hepatic duct is where the bile produced by the liver first flows and then it has two choices it can either go down the bile duct and straight into the duodenum or the smooth muscle around the cystic duct can actually squeeze it back up and into the gallbladder and then when you eat a meal that has fat the smooth muscle squeezes the other way isn't that amazing and pushes the bile down into the duodenum and then what is the purpose of this great bile let's write that in green so the purpose of file is to break fat into smaller droplets that lipase can act on so if you have lipase but you don't have enough file you actually can't break down the fats in your diet very completely and you could end up with fat in the stool and that can be a sign of liver problems if there's like fatty streaks in the feces they should not be there a fancier word for what bile actually does is called emulsifier an emulsifier is what I just defined right there it breaks the fat into smaller droplets so that the lipase can attack the fat from all sides of it more surface area and break it down into fatty acids and glycerol okay so now let's talk just a little bit about what happens in the liver once the sugars and the amino acids are broken down and absorbed into the bloodstream what they do is they go straight from the blood vessels of the duodenum to the liver through a vein called the hepatic portal vein I made that in purple it's important it's purple it's not red or blue like an artery or a vein it's purple because it is very special it's called the hepatic portal vein and the words all mean something important hepatic means that it has to do with the liver portal means it's a doorway between two organs basically between the small intestine and the liver and vein means it's going back toward the heart so it's not going to be oxygenated it's going to be deoxygenated but what is really interesting is because it's a portal vein and it the blood that is draining from the small intestine goes to the liver it is full of nutrients after a meal so it drains blood from a small intestine and so that means after a meal there's going to be tons of glucose tons of amino acids here now notice I didn't mention the fats and that's because the fats from the meal actually go into our lymphatic system and then join up with the blood vessels near the heart so they go on a different path and they're not modified directly by the liver so over here in pink you can put the paddock artery and this is where the liver gets its oxygenated blood from this is the hepatic artery and so that's gonna have oxygen in it for the liver it will also have whatever glucose happens to be in the blood at that time but after a meal the hepatic portal vein might very well have very high amounts of glucose and we can't just let those back out into the blood or someone would have really high blood sugar so let's put the hepatic vein right here and notice I made it in blue like a traditional vein it's heading back to the heart but it is going to contain modified levels so mod mod for modified levels of sugar and amino acids so that the blood doesn't just get blasted with whatever sugar might have been in the meal that you just ate okay so now what happens if there's too much sugar coming through the liver and our body knows it's gonna be over a hundred milligrams per deciliter which would be too much sugar or maybe above 150 or something well if there's too much let's see let's just use a black pen for this so excess glucose from the hepatic portal vein will be stored sorry well then we'll use this fancy word right here glyco Genesis and even lipo Genesis if you have a bunch of excess sugar you can actually store it in the liver and in fact if the situation gets bad enough then that can lead to what's known as fatty liver disease but what if there's not enough glucose because then you're gonna pass out right what if you're between meals and there isn't very much glucose coming in through the hepatic portal vein now what the liver still saves the day it can perform glyco genomicists to break down the stored sugar it can perform lipolysis to break down the stored sugar and it can even perform another process called gluco neo Genesis gluco neo Genesis and this process can make sugar from fatty acids and from amino acids so it can break down fats and proteins or use those to make new glucose so again if you just ate a meal and there's a lot of sugar coming into the liver your liver will store the excess as glycogen or will store the excess is fat if there's not very much glucose coming into the liver then the liver still has to make sure you have enough blood sugar so you don't pass out so then it can break down the glycogen in a process called glycogenolysis it can break down the fat in a process called lipolysis and it can make new glucose from fatty acids and or like actually glycerol and amino acids

Channel: susannaheinze

Views: 74,075

Rating: 4.9191918 out of 5

Keywords: duodenum, pancreas, bicarbonate, bile salts, gall bladder, digestive enzymes

Id: yhBmX1DI64w

Length: 18min 10sec (1090 seconds)

Published: Wed Dec 16 2015