okay so this is the duodenum so we just finished the stomach the whole goal of the stomach is to Mixy Mixy journey journey and pulverize right the whole goal the stomach is to take that bow list which is the ball of food and convert it into Chi which is the liquidy goodness that's because as we head towards the small intestine the small intestine is what quote-unquote feeds us by that I mean it's the one that absorbs the nutrients into your bloodstream and so although 21 feets really long that's not when you think that we have to absorb every single nutrient for all of the cells in your body so the first segment is the duodenum and so this is coming off the stomach it's kind of weird and c-shaped and so it's about 10 inches long and so the inside of your small intestine I want you to visualize as being kind of like lined with paper towels so if you go and throw a paper towel on a chunk of cat vomit that's not gonna do anything right like if you throw a paper towel on liquidy cat vomit it's just gonna suck it right up but like chunky stuff paper towels can't absorb so foods the same way it's like if a solid chicken nugget is sitting there in the duodenum it can't be absorbed into the bloodstream this is also the part where bile is gonna dump in so your gall bladder your gall bladders job is to store the bile but the liver actually makes the bile and so what bile does is it emulsifies fat and so emulsified just kind of means takes big chunks and makes it into little chunks it's really hard for us to process fat so about the only thing we can do is take like big chunks of fat and like kind of separate it like oil droplets if you've ever seen like a Dawn dishwashing commercial where they kind of show the pans like kind of soaking in the sink and like the fat bubbles up and that's basically what emulsify is it's like we're just separating big chunks into little chunks so bile does this so bile and fat and so this little common bile duct that's in this picture you can see how that common bile duct is coming down off the gall bladder and going into the duodenum and so if you see that tiny little sphincter in the duodenum I love a good sphincter that's such a fun that is the sphincter of Oddi which is super fun or you can call it the hepato pancreatic sphincter but what that little sphincter is for is to control the passage of bile so you only dump bile into the duodenum if you've had some fat otherwise why would you bother we're also gonna see that pancreatic secretions are entering here and so they're coming through that little sphincters of OD as well and so this guy's got a lot of jobs lots of digestive enzymes to help us break down food but also we're gonna neutralize the really acidic chyme that's coming off the stomach so the stomach remember has that mucus layer to protect it from all the acid the pancreas is gonna have to neutralize that acity goodness as it heads into the small intestine because the small intestine isn't protected from that digestion and absorption so digestion meaning we're still breaking things down an absorption of almost everything is going to start now so the small intestine is where we are sucking things up if it doesn't get absorbed in the small intestine it's gonna leave in your duty and yes duty is the technical term okay so if it's all about breaking things down we are going to see an insane amount of enzymes so enzymes remember help speed things up help speed chemistry ups if you go back to like the first lecture in this unit I basically said that macromolecules will break down on their own like if you leave food out it's gonna rot right but we don't have time for food to just rot in our stomach we don't have time for the food in our body to liquefy on its own because we'd starve to dust so the enzymes are here to speed up this process so enzymes usually in an ASE so that's how you usually identify them and they're often named for the job they do which is kind of nice okay so we have pancreatic amylase so we saw amylase already they should have named it starch ace remember but they didn't so amylase breaks down starch so remember starch is a huge molecule for our body to break down plant material is difficult for us to process and so we get the jump start in our saliva to help us process that so it's the same thing we're adding just to help us continue to break down starch because our intestine is pretty long but it's not that long in fact if you dissect an animal and stretch out its intestines you can tell what they're eating so like vegetarian animals animals that only plants their intestine is freaking huge it is so long because that plant material has to stay in there a really long time to get broken down whereas if you're a carnivore your intestine is relatively short because meat is pretty easy for us to digest so we're an omnivore we're in the middle so our intestine is not long it's not short it's kind of in the middle and so for plants we kind of need this additional assistance so pancreatic lipase lipase from lipids helps us break down fat trypsinogen is gonna split proteins and so if you remember we had pepsinogen in the stomach and it had to be converted into pepsin remember how important that was we couldn't have kept pepsin just running around in our body because our body is protein based and we would like eat our own bodies so it's the same thing here we cannot have trips which who which their job is its job is to split proteins just like pepsin the name is very similar we can't have trypsin in your small intestine all the time because you would eat your small intestine so we want this activated when there's protein in the food you're eating so the pancreas secretes trypsinogen that has to get activated by an enzyme called entero kinase so entero kinase is job is to turn trypsinogen into trypsin just like we had pepsinogen being converted into pepsin whenever the acid in the stomach was present so trypsin is enough you do not have to know chemo trypsin and carboxypeptidase those also split proteins but let's just do trypsin splits proteins it has to be activated by Antero kinase because normally you just have trypsinogen being secreted then we have pancreatic nuclease that's gonna help us break down DNA and RNA and then we have bicarbonate ions coming off of the pancreas which function like Rolaids so the whole goal is to neutralize that acidic chyme the stomach in order to do its job has to be extremely acidic but we don't want to burn the crap out of our intestines so is the the time moves on from the duodenum and I really like this picture here that I stole from the internet so the duodenum is that little C shape that's on the backside there we're gonna move into the Jew genome so I remember this D ji which is really stupid but it's kind of like BCS off the heart right that didn't make any sense either so d ji is the order duodenum jejunum ileum so if you look at the difference here in this picture between the jejunum and the ileum there really isn't one right other than the fact that they've colored it like purple and kind of a beige color that's because there really isn't a difference it's like it all looks exactly the same I'm not even sure why it has to have different names because even its function isn't that different so the genome were in the top part of the small intestine digestion absorption of carbs protein and fat continues so we're still breaking things down because of all those enzymes that we got from the pancreas but the biggest thing we're doing is sucking it up we want to make sure we're absorbing it into our bloodstream the last stretch of the small intestine is the ileum so this is an additional 12 feet and so again not a lot of difference between ginam and ileum so 12 feet of this but this is the last opportunity you have to digest things break them down and absorb them it's the last opportunity that we have if we do not get these nutrients into the bloodstream once we head into the large intestine its dust its destined to exit your body it's destined to become duties so it's very very important that the small intestine grabs everything that it can grab so although your mouth to anus tube is technically the gastrointestinal tract and the biggest part of digestion along the way we have a lot of things a lot of organs that add things to make digestion better so it's kind of like your washing machine if I just put clothes in my washing machine and started it no soap no bleach no fabric softener nothing my clothes would get kind of clean right just mixing with water but that's not enough I mean we want to have stains removed we want to have you know odors removed it's like there's more to laundry than just the water so digestion like that if food moves from your mouth to your anus you would digest some of it but not great like just like the washing machine so you add Tide Pods you add fabric softener you add bleach depending on what cycle you're on well along the way our gastrointestinal tract meets a lot of glands like the liver the pancreas the gall bladder just to make sure the salivary glands to make sure that we're adding like all these chemicals that just make digestion better so the liver plays a huge role in digestion so this guy has a lot of functions we've seen the liver and other chapters but he plays a huge role in digestion he is the largest gland in your body I mean the liver is huge he metabolizes helps you break down carbs lipids and proteins but he also makes all those blood proteins when remember when we did capillary exchange and we had albumin and fibrinogen and the globulin being those plasma proteins that were in there so the liver makes those the liver stores things like vitamin b12 which helps you make red blood cells and glycogen which remember glycogen is how you store glucose like all night long when you're not eating you still need to make ATP we're gonna filter the blood now in all fairness remember that's the spleens job the spleen is the red blood cell graveyard where you're really breaking the blood cells down but the liver can do that as well and so then we use the heme from the breaking down of hemoglobin and we is the like the the iron components there to make bile pigments especially Billy Rubin and Billy Verdun so your feces has certain colors this is such an exciting chapter isn't it Billy Verdun means literally green Verde means green and Reuben is kind of like a yellowish kind of red and so when you kind of combine all those colors you get the the brown color of feces one of the biggest things the liver does is destroy toxic chemicals thank goodness right so this guy detox is alcohol which is very important certain drugs and certain other chemicals so your liver is kind of cleaning your bloodstream excess alcohol leads to cirrhosis so cirrhosis is scarring of the liver so your liver regenerates it just regenerates really really slow but like you can donate part of your liver to someone it'll grow back but it takes a really long time and so if you drink a lot like three or more drinks per day every day sometimes the liver just can't take it anymore and so it will develop fibrous connective tissue or scar tissue so you no longer have the liver cells in there whose job is to do the detoxing you're getting scar tissue built up so again we just call this cirrhosis tylenol can do the same thing if you drink so tylenol and ibuprofen are processed two different ways in your body so if you drink alcohol you should use ibuprofen because otherwise it accelerates the damage of the alcohol like the chemistry involved of when you break down tylenol it builds up a chemical that the alcohol actually kind of like has a synergistic effect where they'll do more damage together so there's a warning on tylenol bottles that say don't take tylenol if you drink a lot but if you have really nasty headaches you can take ibuprofen and Tylenol at the same time because they're processed differently by the body so it's safe to take both my dentist recommends this for toothaches all the time please like take like three ibuprofen and three Tylenol which makes me feel kind of crazy but they're processed differently so it's not dangerous the liver helps with with digestion because the liver secretes bile so bile helps us break down fat and so the liver makes bile and the gallbladder stores it because you never know when you're gonna have a high fat meal right I mean frankly every meal I try to have a high fat meal but you want that bile when there's fat ready when there's that present the liver also removes the cholesterol from the blood so cholesterol is an important thing we have to have cholesterol in our diet for our cell membranes cholesterol is also the Lite framework for your sex hormones but some of us get too much in our diet or some of us our liver actually kind of over produces it so it the your liver is making the cholesterol and then dumping it into the blood to be used to make bile or bile salts so there's two different kinds of cholesterol you have high density and low density so the high density is the good one so this will remove the cholesterol from the blood and bring it back to the liver to be made into by if we look at the structure of the liver which we don't do too much with this microscopically so there's really only a few things that I really want you to know from this slide one it's highly vascular so your liver is really really bloody if you eat liver if you've ever seen raw liver it is it's just bloody as hell but that makes sense right because it's cleaning the blood so it has a fibrous outer capsule so it's kind of got a tough outer coating and it's broken into lobes four major lobes which we'll have in lab and further broken down into these little lobules so you don't need to know the details here okay all I want you to know from this so far is it's bloody as hell okay so then there are the cuff ourselves which again you don't need to know but if we think of their function these cells are basically just macrophages and so remember macrophages are the immune cells right so again this makes sense that your liver would have tons of macrophages to kind of clean the blood so all I really want you to know from this slide is liver is bloody as hell and it has these macrophages to clean the blood in this picture the liver has been removed but that was so we could see the gallbladder because it's kind of peeking out from below so if you look at that little tiny torso picture it's showing the liver and the gallbladder is behind it so the whole point of the gallbladder is to store bile and secrete it when you need it so if you look at this picture you have that bile duct that's gonna bring the bile down and dump it into the duodenum and so if you look at that picture it says a Patou pancreatic sphincter that's the sphincter of Oddi and that is to control the bile because you don't walk by your washing machine and throw in a tide pod just because you're there right you're not gonna dump bile if you're eating french fries you're going to dump bile when you're eating something really really high in fat which I guess French fries are high in fat because the way they cook them God love some french fries okay but otherwise when you're eating something like really really high in fat like cheese or ice cream something that has a lot of fat you're going to dump this bile down this common bile duct otherwise we store it in the gall bladder so the liver makes it and anything excess we just back it up throw it in the gall bladder so bile has kind of a greenish color to it which is why gall bladders are green so even on cadavers gall bladders are green which is kind of nice so there's bio pigment in there there's bilirubin which we saw before with hemolytic disease of the newborn so buildup of bilirubin can give you jaundice you know but ideally you're processing the bilirubin to make fecal matter we have bile salts which help us break down fat and increase fat absorption it's like you're taking big chunks turning them into little chunks so if I'm trying to absorb jello with a paper towel a big chunk of jello isn't gonna work right but if I can kind of get it into like little droplets of jello it would be easier for our bodies to absorb there's water and bile there's cholesterol there's electrolytes bile is not an enzyme this is a crucial thing because if you remember enzymes a little bit of enzyme can go a long way enzymes are like a domino effect one molecule of enzymes can work on like millions of chemicals so it's like a key that you can just use over and over and over again bile is not like that so the amount of fat you have to break down you're gonna have to release like a certain amount of bile to do that so if you have a lot of fat you're gonna need a lot of bile and every time you have fat in your duodenum you're gonna need bile to break it down and you're gonna need quite a bit of it so this is why we have the gall bladder because we need to be able to store that bile for when we need it if we have a high fat meal so people get their gallbladders removed my mother-in-law just had hers removed it changes the way that you eat forever because you can still break down fat otherwise we would be dead because you got to have fat in your diet but if you don't have this gallbladder to store it all you'll have is the bile that's coming down if you look at this picture the hepatic ducts that's coming straight off the liver so you're always secreting bile it kind of a slow rate but like if you decide to get like a huge meal at McDonald's sorry I'm gonna sneak excuse me if you get a huge meal at McDonald's that has tons and tons of fat in it you're probably gonna get really sick without your gallbladder you'll have to go to the bathroom right away excuse me juice no my cat is sitting right next to me so I pray getting cat hair in my nose and so it just changes the way that you eat forever without your gallbladder you'll not be able to eat these intense high fat meals in one setting anymore without kind of paying the price so this just describes the the anatomy which we'll have in lab or you've already had in lab of the pathway of how bile travels so the bile goes into the right and left hepatic ducts which join together and become the common hepatic duct that's gonna join with the cystic duct coming off the gall bladder to form the common bile duct which I know is a little bit crazy so the common bile duct is what dumps the bile into the duodenum through the sphincter of Oddi which is what i use or hepato pancreatic sphincter which just means liver and pancreas so that sphincter is there to control the passage of bile cuz it's like you're not dumping bile unless there's fat in there if you ate a salad for lunch good for you you don't need a lot of bile for that so if you have excess bile it go it backs up through the cystic duct and gets stored in the gallbladder but the gallbladder is very very small it's it's I can't even think it's a little bit bigger than like a golf ball it's not a very big structure and so we can't really waste the space and so your body actually like kind of absorbs the water because you know water is a big waste of space a lot of like cleaning supplies are doing this now where it's like the instead of you know selling you like a big bottle of detergent or a big bottle of light cleaning like window cleaning stuff they'll they are selling us this concentrated and then you just add your own water cuz it's like why would pay for these giant bottles of cleaning stuff that's mostly water so a lot of companies this way they're reducing like their packaging and they're plastic usage and their shipping costs are a lot better right cuz like they're wasting a lot of energy shipping these huge containers that are over half water well you can just add water on your own at home so if you buy something concentrated you have to water it down right so that's what the bile is the waters been sucked out so the bile inside the gall bladder is really thick it's not very liquidy because it's been from the waters been removed but it's an easier way to store it so this picture here is just showing the anatomy so you have the left and right hepatic ducts they're coming directly out of the liver they merge and you have the common hepatic duct then you see the cystic duct and it has the coming straight off the gallbladder and then the cystic duct and the common hepatic duct are going to merge into the common bile duct and then the common bile duct comes down and it's going to hook up with the pancreatic duct coming out of pancreas and then we have the sphincter of Oddi or the hepato pancreatic sinker controlling its passage so when you need bile we have another hormone that cholecystokinin which we saw before CCK this guy is released when there's fat in your food so when there's fat in your food this hormone gets released and this is what triggers your gallbladder to squeeze so the pad oh pancreatic sphincter relaxes and then the bile travels through the cystic duct to the common bile duct into the duodenum so that's how it quote-unquote knows there's food that there's fat in the food it's cuz of this hormone but just like anything else in our body what can what's good for us can sometimes go naughty okay so like I said my mother-in-law has had her gallbladder taken out because it was inflamed and causing her a lot of pain so people can get gall stones in their gallbladder and so if you look at this picture compared to a quarter or compared to a pencil these things are no joke right those are pretty pretty big can you can imagine like something like this in your body inside an organ kind of just irritating the crap out of it so golf stones can be made of lots of things but what I want you to know is they're usually made from cholesterol so the liver secretes cholesterol so if you have just a very aggressive liver you might end up with with these so hepatic cells themselves may secrete too much or if the gallbladder gets inflamed it might just cause gall stones on its own so either way you're getting kind of these chunks inside the gallbladder so bile salts are there to emulsify fat so the whole goal is to just take big fats and make them into little droplets so that way your body can kind of process it a little bit easier bile helps you absorb fatty acids cholesterol which of course we don't need a lot of but we need some and there are certain vitamins that are fat soluble so you can only absorb vitamin A D E and K in the presence of fat so if that's an important part of your body to help you and to digest fat as an important thing that the gallbladder normally assists with but when it's all angry it's not gonna do that good of a job but like I said you can survive without your gallbladder it's not ideal and it will change the way that you eat you won't able to handle high-fat meals but because the liver makes the bile you can survive without your gallbladder you can't survive without your liver it does too many things as we just saw in previous slides