hi and welcome to another video on the digestive system we are going to start with the lower oops there we go lower GI tract organs and proceed from there so sorry about that oh I'm not sharing share my screen there we go okay get rid of me oops there we go all right finally okay so in the lower digestive tract so we're going Beyond this stomach canal and we are going to go into uh continued digestion of the food that we ate and absorption so we are also going to use the lower GI tract organs to get rid of all of that stuff that we cannot digest and absorb so um elimination of indigestible and unabsorbable materials we'll start with this small intestine um three sections duodenum jejunum and ilium then the duodenum is the considered still part of the upper GI tract um and then as you connect or continue on into the jejunum then I guess technically you're into the lower GI tract but I don't really care so what is the duodenum going to do we're going to receive chymes so that material that was made in the stomach mixed with uh gastric juice and and digested down as far as the stomach is able to digest We Now call it time um well then mixed with accessory organ secretions from the pancreas in the liver and then um most chemical digestion there's not going to be any past the ilium but the majority of the chemical digestion is going to take place in the duodenum and then some in the jejunum and then the absorption will take place primarily in the jejunum and the ilium um let's see then we have the accessory organs so secretions of bile from I mean pen from the liver so bile is produced oops by the liver and then we have pancreatic juice which we'll get to in just a second so once the bile is secreted by the liver it's going to be concentrated and released by the gallbladder and we need to to take some of the water out so we're going to leave it in the gallbladder for a while and that will increase the concentration of the bile salts that are within the gallbladder and then pancreatic juice is has digestive enzymes in it but it also has bicarbonate because one of the things that we're going to need to do is neutralize the acid that's the acidic kind that's coming from the stomach and so we're going to use bicarbonate from the pancreas that to uh neutralize that material then the large intestine absorbs water electrolytes and vitamins and then feces are produced and eliminated through the anuses so we know so there are the sections so you can just look at that um just putting in here autoimmune disorders Crohn's disease and and uh ulcerative colitis so it depends on where we are attacking so this can Crohn's can be small and large intestine and because it's autoimmune it means your own immune system is attacking the intestine and so cramping and diarrhea that you get with crohn's and it's it's just chronic you guys it just goes on for a long time well possibly for the rest of your life oh and then so this is IBD inflammatory bowel disease because we're going to look at syndrome in a minute um and then ulcerative colitis is only in the large intestine and typically it's further down in the intestine more like sigmoid and descendant colon Could Happen anywhere but um colitis think colon large intestine okay inflammation of the colon all right um but both are autoimmune now inflammatory I mean irritable bowel so we had inflammatory bowel disease irritable bowel syndrome this is essentially you just get diarrhea okay very common uh abnormal function of the colon more common in women than men cramps bloating constipation diarrhea and it's not a disease it's not a um is not autoimmune or anything and we can treat it with diet medication stress reduction there's just a we can um work on reestablishing your normal flora in your colon so your um your gut microbiota so just your germs that live in I guess I shouldn't call them germs they're just your intestinal Flora okay the little microbes that live there okay um so if you can reestablish that well I guess you would do that with diet so um some probiotics for example and we'll talk more about that when we get to the large intestine all right so small intestine can also be referred to as the small bowel it is a very long tube but it is small in diameter small in diameter okay and uh hangs out there about at least 12 hours while it's being digested and absorbed and we're going to absorb most nutrients large percentage of water electrolytes and vitamins okay there's going to be about 8 500 milliliters a day that pass through your stomach in your small intestine of that about 6 500 milliliters is absorbed at the small intestine okay so that percentage-wise let me just see that's like 80 percent um that's 76 76.4 so we'll we'll just say about 77 percent efficient okay at absorbing your food then that 2 000 milliliters that goes into the large so this could be in your large intestine we're going to absorb about uh 1700 milliliters of it okay and so 17 divided by whoops 1900 divided by 2000 is oops is 85 percent efficient so here's large intestine is actually more efficient in absorbing food well what it's nutrients and water then the small intestine actually is so I think that's pretty interesting all right so let's look um just real quickly at the section so the duodenum first segment originates at the pyloric sphincter C shape continuous with the jejunum don't need to know about the Dual flexure don't worry about retroperitoneal it just means that it's behind the parietal peritoneum does receive chyme from the stomach and then gets things from the gallbladder liver gallbladder and pancreas okay the jejunum is the middle section about two-fifths the total length of the small intestine this is where we do chemical digestion so what didn't happen in the duodenum see did we put that um we'll just put that in here chemical digestion because all of the enzymes that and the other substances the gland secretions that that come into the duodenum are going to act on that kind that's in there but we're going to keep sending it on through the jejuna because the the small or the uh tuodenum is only 10 inches so it's not very long so it's not significantly long enough for you to be able to do the bulk of the chemical digestion so we're going to continue it on in the jejunum and then do nutrient reabsorption okay then the ilium is the last three-fifths it's going to end at the ileocecal valve as we go into the large intestine so it's the sphincter that controls the material of into the large intestine and continues absorption we're really not digesting by the time it gets to the ilium we've digested it down to the to the level that you can absorb it and and so then we'll absorb it in the duodenum I mean in the jejuna and then we'll absorb in the ilium as well um I'm just going to put this in here and we're going to put absorption because I probably talk about it later oops absorption of 85 nope 95 percent of bile salts so this the stuff in bile that we'll talk about in the digestion video um that that is necessary to achieve its function um it's recycled so um so 95 of it is recycled and five percent of it then is is actually um lost um in the feces okay so uh when it's important that we know that the small intestine is designed to maximize absorption so what we need to do is increase surface area so the first way that we're going to do that is with what are known as circular folds or we also call them like a circularis oops okay circularis so I'll show you what those circular folds look like in a minute but they're the folds of both the mucosa and the submucosa layers of the small intestine increased surface area for absorption they slow the movement of chyme more numerous in the duodenum and the jejunum and less than the ilium all right so here's what it looks like so I'm going to take the mucosa and the submucosa and I'm going to fold them so can you see how they're all folded like this or they're both folded like this so this is like taking your carpet in your house and scrunching it up so that there's all these little Hills and Valleys in your carpet but then you still have stuff underneath your carpet like your pad and that kind of stuff all right now the reason why I talk about carpeting is uh what we're going to see in the in the next video or in the next slide so um first we start out with the circular folds I still need some more um uh surface area so now I have billi so now I'm going to take my mucosa and I'm going to fold it into little finger like projections um much larger and more numerous than the jejunum um the ilium is going to cover over that lamina propria which is that underneath layer where the capillaries are um so capillaries are here underneath the simple simple columnar epithelium of the mucosa increases the surface area again for absorption and secretion contains oh there it is arterial capillary Network in a venule should have read a little bit farther and then we also have a lacteal so this is a single lymph capillary within each villus and we'll take a look at that in a minute uh the reason why we need to have lacteals there is because fats will not be absorbed into a capillary Network only water and the rest of the nutrients will go into the capillary network but the the lipids have to go into that more permeable lymph capillary so lipids and lipid soluble vitamins will enter through the lacteals and then eventually go back to circulation all right so here's how a villus works so here is one fold so I have this one fold now on my fold at my carpet has let's say I have shag carpeting so you know it's in your grandma's basement so here would be the shags of my Carpeting and so each little strand of my carpeting is a villus so each one is a villus and we'll look at that in a minute so it's just going to be one like that and inside we're going to have the blood capillaries and then we're going to have a lacteal or a lymph capillary inside of there so not only is the mucosa folded but then the epithelium is folded again into these little um finger-like projections called Villi or one is a Villas then if that's not enough on the top of those simple columnar epithelial cells that we find on the Villi their top membrane their apical surface membrane is going to be folded into microvilli so these are going to be individual columnar cells and then each of the the surface of the cell membrane or the cell membrane up at the top on the apical side that is folded so extensions of the plasma membrane simple columnar epithelial cells again increases the surface area of the small intestine we refer to that as a brush border and it'll make sense when we talk about digestion and have there are enzymes embedded in that wall this is also so this is for chemical to finish the chemical digestion but also for the transport of digestion products because what we're going to have are I'm gonna switch colors for this um we're going to have the transport proteins for facilitated diffusion remember you can absorb calcium you can't absorb glucose right through the cell membrane and so what we're going to do is fold the cell membrane and then embed those transport proteins so these are for facilitated diffusion transport proteins oops uh into the cell membrane and in fact the most important transport protein that we have is called an sglt1 which stands for sodium glucose transporter number one and that will do the um secondary active transport of um sodium and glucose through the membrane that we'll talk about later so in order to maximize the number of transport proteins absorbed the most food that we can and also to finish chemical digestion we'll have those brush border enzymes I'll just show you where they're going to be do it of color so the brush border and you can't see that there we go okay so the brush border enzymes then will be these orange or yellowy gold colored things and they too will be embedded in the membrane in and that those microvilli will again give you more surface area to implant the implant I don't know insert there we go insert the brush border enzyme proteins and the transport proteins okay so here is what a villus looks like so let me just get a color um all right so up in here all inside of there and inside of here and inside of here will be the blood capillaries and a lacteal so they'll be all inside of there then here is the let me get my laser pointer okay then all around here is the simple columnar epithelium so you can see the nuclei are these purple circles and then the cells and then those white dots those are all goblet cells so now that epithelium is going to go around all of the Villi here and then if we look at a single cell so this is just one single um simple columnar epithelial cells and we're cell and we're only looking at its apical surface so here's the inside of the Lumen you can see how the cell membrane is all folded like this creating that brush border because it does look like a brush like bristles on a brush but those are the microvilli and so um again we can absorb so much stuff because of the plyka circularis or the circular folds the Villi and the microvilli so make sure that you remember what are the structures that are going to increase surface area for absorption within the digestive system so they will be the microvilli the Villi and the circular folds whoops there we go like a circularis okay all right um we're not going to worry too much about the intestinal glands okay um goblet cells produce Newson precursors of mucus so there um between the simple columnar epithelial cells or what we refer to as enterocytes okay then we have intraendocrine cells so these are going to release hormones just like they did in the stomach um cholecystokinin and secretin then we have Panic cells we're not really going to worry about that just know that the small intestine two is going to secrete lysozyme and other antimicrobial agents oh where have we seen lysozyme before Lac it's a cool thing lacrimal fluid your tears um saliva swept okay and then um we have these submucosal glands oh my gosh these guys are called the crypts you don't have to remember this but I just love their name liebercoon the crypts of Lieber oh don't you love that name Mr liebercoon anyway um they're going to produce mucus protects the duodenum from the acidic kind so our little Crypts of of liebercoon are right in here right there those are those little Dippy thingies and then we find all of our little cells in there and they're going to protect us okay so this is what a villus looks like so here to my later pointer all right so here are the simple columnar epithelial cells and then on their top surface will be those microvilli these uh simple columnar epithelial cells are also known as enterocytes so in case I mentioned that again then there's the goblet cells that are producing mucin well I always say they produce mucus it's going to mix with other like water basically mucin is an N is a protein and it's and I think I've mentioned I know I mentioned this before that mucin is what makes your spit stick makes your spit come out in strings so that you can't just spit like you know how you spit water if you just shut water out of your mouth Waters comes out but with your spitting saliva extremely and it's because of the mucin Protein that's comes from the gobble cells and then here's the enteroendocrine cells making the hormones cck cholecystokinin and secretin so cck is cholecysticated and then the lysozyme okay so there's a beautiful Villa so you're going to have millions and millions and millions of those villi now in order to um move the uh um or not move but to mix the food we need to not just have peristalsis going on but we want um uh uh um mixing oh I just said that segmentation I can't think what that was called all right so the smooth muscle of the intestinal of the small intestine is not just going to shoot forward I mean shoot the food forward it will produce I mean Propel the contents by peristalsis that will happen but we're going to mix back and forth so different sections of the small intestine will squeeze forward and then they'll squeeze backwards and forwards and backwards and we just keep that forward and backward motion moving all the way down the length of the small intestine so that I get segmentation and peristalsis happening at the same time okay um and and so the purpose of that is to mix the kind with the gland secretion so that we can maximize or optimize the connections between the enzymes and their substrates that we need to to dissolve plus it moves the guy the chyme against new areas of the brush border so those brush border enzymes can digest the food one and the transport proteins can absorb it as number two um okay so let's see what I want to know about this so so say oh they spelled time wrong all right segmentation early intestinal phase is the last phase of what's going on remember we had a cephalic phase gastro phase and gastric phase and an intestinal phase of gastric secretion and so in the intestinal phase we will be moving the food along uh we will have these little pacemaker cells so they're going to um uh those interstitial cells of call are going to create the um ber the basal basal electrical rhythm yeah the ber so that's the waves of of um of uh depolarization I guess that's how I want to talk how I want to explain it so in the myantaic and the submucosal nerve plexuses it's just yeah it's the waves of depolarization that are happening through those neurons there and um and that will be transferred to the smooth muscle and into the muscularis through Gap Junctions and then um the contraction of the muscularis will happen and will move our food along so segment station is going to happen first and then peristalsis um once we start mixing the food then we want to we're going to want to move it down so we have this modalin hormone that's produced that released from the duodenum that stimulates the um um rhythmic contractions of the of the muscularis now we get this migrating motility complex um every so many hours what's going to happen is that your whole digestive system is just going to wash through so you're going to get this big push of material through until everything's into this large intestine so it's like a mass dumping kind of thing that's going to happen and so we're just pushing everything through every now and again all right um okay so I don't have your notes out in front of me so I'm not going to worry about the gastroilio reflex um the uh ileocecal sphincter or the ileocecal valve either one is um going to be closed and when food is in your stomach then and cck is uh secreted in response to that to to finish up gastric secretion the cecum relaxes and the sphincter relaxes and contents move from this ilium to the cecum and then the ileocecal valve prevents the backflow of material from the cecum into the ilium I'm not going to worry about the biliary apparatus and not going to worry about any of those sphincters I do like that paddle pancreatic sphincter we used to call it the sphincter of ODI I just like that name okay so we're not going to worry about that either all right but what we do want to just really quickly take a look at is how these guys are all connected together so here's where our liver would be and so these right and left hepatic decks will secrete the bile into the common hepatic duct okay and then the common hepatic duct is going to send its secretions of bile into the cystic duct and then when we're when we're um digesting food then we'll send the um uh gallbladder or the bile sorry I had to stop and think I had to send the bile through the cystic duct which will then merge to form the common bile duct right here or the hepatic and cystic ducts come together and then we're going to join the pancreatic duct together with the common bile duct and then we'll go into the duodenal papilla in where the sphincter of ODI is and that one right hepatopancreatic ampula and sphincter and so that's where all the secretions that come from the liver gallbladder and pancreas will all enter the duodenum right there and that's all I care that you know is that they all come together in the duodenum right there all right what's your liver for so um production of bile is one of its functions I don't know that I would say it's main function we're going to store carbs oops store carbs oh man as glycogen so we're going to start store glucose as glycogen we're going to detoxify what we eat absorbed food that's been absorbed into the bloodstream from the digestive tract through that hepatic portal vein detoxify detoxify absorb food make albumin uh make colliding proteins that over here hey so your liver is involved in blood clotting your liver is involved in maintenance of your water water homeostasis and uh makes bile stores glycogen detoxifies food does a bunch of other things I'm not oh um when you take a drug part of this detoxification process is um sometimes you need to have a drug metabolized by the liver before that drug becomes functional in you and so it has to you consume it has to be an oral and then you um you go into the liver so once you you can you take that medication orally it'll be absorbed it'll go right to your liver before it goes anywhere else and go to your liver and then get um uh changed metabolized into its active form see um okay so that's that I don't really care about the rest of this and don't care about the four different livers four different livers four different lobes uh don't care about this is all just anatomical stuff um not gonna do any of this just this okay this hepatic portal vein information oh stores fat liver also stores fat that's another thing the fat soluble vitamins and cholesterol so it carries deoxygenated nutrient-rich blood from the capillar's bed is the GI tract spleen pancreas um 75 of blood to the liver okay once it's been out in the digestive system um okay stellate cells let's just kind of remember these guys stellate cells or Cooper cells are macrophages they are resident macrophages so they live in your liver all the time they don't live in your bloodstream and then come out um and so if you consume anything that's bad that might get into your liver then those resident macrophages can destroy that liver cells are also called hepatocytes there's just that so that you know that uh the type of capillaries that we find in the liver are sinusoidal capillaries really big Blobby ones so that we can process the food that's coming through them okay so bile what is that it's a live it's secreted by the liver cars it is not a digestive enzyme not a digestive enzyme um so bile has or has no I guess that's what they were saying no digestive enzymes in it it only has bile salts that help with um and lecithin which is a fatty acid that helps with the um emulsification but we'll get into that when we talk about chemical digestion so water bicarbonate ions definitely bicarbonate because if you're still dealing with acidic kind by the time it gets into the duodenum it's still acidic so the bile goes in there to help neutralize that acid chyme and then bile salts those are the guys that are going to do the job and then pigments pigments from blood from heme so the heme pigments uh you know if you're if you have a bruise and you first look at the bruise and it's kind of a purpley blue color and then it goes through stages of green and yellow colors that's because we're processing the heme we're breaking down the heme that's in hemoglobin take the iron out but the heme has the color to it and so that heme is what makes you look yellow it's now bilirubin by that time bilirubin and so your liver is going to take that out and put it in the bile and then excrete it in your feces and that's what makes your feces Brown is it the bilirubin that's there uh so if you have a dysfunctional liver because you have hepatitis or you have cirrhosis of the liver because of alcoholism or you have liver cancer or whatever is wrong with your liver you will stay orange because that bilirubin isn't being taken out of your blood and now it it's just all traveling through your skin and um through the capillaries in your skin and that's the other thing I was going to say um you look you have jaundice oh and your feces will be white so if you have liver disease you will be jaunticed and you will have white feces because there's no blood pigments in there because it's not cleaning it out cholesterol is an important component of bio and so this is we have to have cholesterol in our body but this is how we're going to get the cholesterol out the excess that we don't need and lesser than the music okay uh I don't need that don't need that don't need that all right so just to review we did this with the blood uh with the blood vessels we did The Paddock portal system so we're going to take blood from the superior interior mesenteric arteries nope Superior inferior mesenteric veins um the splenic vein the left gastric vein and we're going to put all of that together so they're spleen in the stomach and enlarge there's the lower portion of the large intestine here all that's going to come together into the paddock portal vein then we're going to go into the liver lobules and we're going to process that blood and then it'll leave the lobules you know go through the paddock veins and go back into the inferior vena cava oh it's just such a beautiful thing all right so cirrhosis of the liver is due to hepatocytes replaced by fibrous Scar Tissue because you drank so much alcohol that um uh Scar Tissue happened you killed your poor little hepatocytes or if you had some other liver disease if too many drugs too many toxins acetaminophen Speedo men often I just don't know how to spell acetaminophen acetaminophen acetamin a acetaminophen anyway uh Tylenol so too many Tylenol too much Tylenol even their NSAID so uh ibuprofen and naproxens and that kind of stuff but particularly acetaminophen is very toxic to your liver uh so you can get um cirrhosis from that um also if you have frequent bio viral infections Hepatitis B or C or a not b or c are going to cause more damage than a but still uh so what did we what are we going to see fatigue weight loss nausea pain and upper right quadrant where your liver is found if it's Advanced jaundice like we said edema because I said hey your liver is responsible for a fluid or fluid balance in your body and if you're not making albumin you are not you are decreasing your um osmotic pressure of your blood and the fluid will come out because of hydrostatic pressure into your tissues at the capillary beds and it's not going to return so you will swell you'll get a CDS this is um swelling abdominally so if you've seen um children for example not because their livers are necessarily dysfunctional but children who are severely malnourished um just skin and bones but they have those really swollen bellies that's because the fluid is being deposited abdominally and the reason why they're not um why that fluid is being deposited there is not because their livers don't work but they're not eating enough protein so that their livers can make enough albumin so that they don't have that so protein malnutrition um we'll see a CDS but we'll also see a CDs in in people with liver failure so somebody with a who's an alcoholic um we'll have a CDS my son's a funeral director and and uh he was telling me about a guy he said Mom I just saw the most swollen abdomen I've ever seen and he says and I took off just there was all this fluid that was in there and I said did he die of liver problems and he said yes and so there it is so um there's that my story about that itching toxin accumulation that's because you're going to get crappy stuff that's out there that's going to irritate you and then toxin accumulation dilated veins of the esophagus just bad stuff because um things are not returning like they should and so there is cirrhosis of the liver um gallbladder all you need to know is that it stores concentrates and releases bile produced in the liver uh that's all I care boom gallstones so this is either in the gallbladder or the biliary apparatus so that's in either the cystic duct or the common bile duct and it's just condensations of cholesterol calcium and by bile salts lots of pain right hypochondriac region right underneath your liver um and there it is you may have to have them removed all right pancreas so the pancreas is function here as an endocrine function as we've already talked about is for the secretion of insulin glucagon to regulate um regulation of blood glucose but its axocrine function is to to produce the pancreatic juice that we use with digestion don't worry about anything else on there all right so we will need to take a look at the histology of the pancreas so I'm going to go to this picture and then um and then we'll go backwards all right so this big pink thing right here is the endocrine structure of the pancreas that's a pancreatic eyelet or an eyelid of longer hunts I love that word that name okay so there's an eyelid of longer hands all the rest of these and here's one and here's one and here's one they're like little cul-de-sacs in your pancreas and we call them acini so pancreatic acini this is an acinous here is one Asus that is your cul-de-sac so you are going to have two groups of cells in your um in your cul-de-sac so you're going to have the houses those are the aciner cells so they're the the bigger houses that can be at the end of the cul-de-sac then the little houses that you have over here are the depth cells the ace inner cells notice they produce the enzyme so amylase lipase proteases and nucleases the duct cells secrete bicarbonate so make sure you know the difference between the two so Ace inner cells produce the enzymes the duct cells produce the bicarbonate okay so a center cells simple keep modified simple cuboidal Sac like acini produce and release the enzymes we're not going to worry about lobules and the different kinds of ducts that you have in there but remember this is its exocrine function so it has to have ducts okay and then the simple cuboidal duct cells to create the alkaline bicarbonate fluid all right so what's going to be in pancreatic juice everything you need for digestion okay so if nothing else works if your saliva isn't working if your stomach isn't working doesn't matter this will produce all of the secretions for all of the digestion of all of the food that you eat okay so no worries everything can be digested by the pancreas so what does that mean what if you lose your pancreas function then you're going to have to take enzymes for the rest of your life to to supplement that so my anatomy Professor my my mentor uh who I just owe everything in my career to um he had he was diagnosed with pancreatic cancer when he was in his late 20s and um had most of his pancreas removed and he uh when I had him he was in his mid-40s so you know like 15 years later after he was first diagnosed with it was when when he was teaching um where I went to school and and um uh he was doing really good and um and uh but we talk about it all the time you know his diagnosis and what was going on and so he was able to manage his life over that you know 15 some odd year period and then I graduated and um saw him a couple of times later um you know five or six years later after I graduated and then um and then about 18 years after I had hymns almost 20 years yeah about 18 years after I had him as like you guys his cancer came back and he died in a like quite rapidly and he died in his early 60s and um but you know so from his late 20s to his early 60s he managed to live without a pancreas but it's difficult so here's what it makes mostly so what's in pancreatic juice mostly water and then bicarbonate from the duct cells and then digestive enzymes from the aciner cells so what are those digestive enzymes so we'll talk at length about this in the digestion chemical digestion video but pancreatic amylase to digest starch pancreatic lipase to digest triglycerides fats lipids that's what you more commonly know them as but you should know them as triglycerides and then inactive proteases just like how pepsin was um pepsinogen secreted from the chief cells of the of the gastric glands in the stomach they have to be secreted in an inactive form so you don't digest the pancreas while they're in there um okay and then digest proteins when they're activated and then nucleases for digestion of nucleic acids okay that is pancreatic cancer um so let's see okay I um so I'm trying to think um how long if he said between symptoms and diagnosis but obviously okay so prognosis is good with early detection so um they they detected it but here was the thing because it says absence of signs and symptoms in the early stages of the disease so um there is an area so um uh upper I'm going to put upper back pain between whoops whoops and scapulae all right this is where his pain was and he had the loss of appetite and weight loss too but um he went to a doctor um and uh when he first started getting this pain between his shoulder blades and the doctor said oh you're just bent over your microscopes he's working on his PhD at the time and they said you know you just look bent over the microscope too much you just it's just back pain you're gonna be fine and um so he was okay fine and but he still felt really unsettled he just he felt like that was not what was wrong with him so we went to another doctor and the minute he told his doctor where the pain was he goes oh my gosh we need to do exploratory surgery on me on you because I think you have pancreatic cancer um because that's a referred pain site for pain in those site in the pancreas is right between your shoulder blades so um sure enough they went in and it was all cancers but they detected it early enough that he was fine so there's that all right now um closest to kind of so we need to regulate the secretion of uh bile and the pancreatic juices so we're going to use two hormones to do this produced by the enteroendocrine cells of the of the duodenum and they are cholecystokinin abbreviated cck and secretin so cholecystokinin's job is going to be secreted so we're going to secrete once there's fatty chymes so receptors for fats in the duodenum are going to stimulate the release of cck and that goes then into the bloodstream to the gallbladder to strongly contract and release bio then it will also release or go to the pancreas not just to release pancreatic juice I'm just going to put this I'm going to scrill that out and I'm going to put enzymes because the cholecystokinin is going to stimulate those a center cells to produce the pancreatic enzymes okay and then relax the smooth muscle so that bile and pancreatic juice can go in the small intestine and inhibit stomach motility it it will and stops the release of gastric secretion so its job is to also help shut down the stomach like we talked about before secreting um this is interesting this is the first enzyme ever discovered first enzyme digestive enzyme I guess we should say um and they just said it's protein so we're going to name it in and we're going to say it got secreted so that's secreting so that was a very long time ago when we first found secretin all right so its job is to stimulate the small intestine or no the pancreas stimulate the pancreas from the small intestine to um neutralize acidic kind so when the chyme is coming from the stomach and it's particularly acidic then secretin from the anterior Endocrine cells will go to the um decks of the pancreas so the duct cells of the pancreas and the liver too but the ducts of the pancreas in particular and stimulate the release of bicarbonate so then that will go into the dodeanum to neutralize acidic chyme and again secretin and cholecystokinin are gastric Inhibitors so they're going to stop the stomach from secreting okay I think that's far enough now so we'll stop here at this video and then we'll start with a large intestine in the next oops in the next let me get rid of that and that's it