the GI tract the GI tract is composed of you the GI tract in the abdomen is composed of the stomach the small intestines and the large intestines and what we're going to do is focus on the stomach first now the stomach has the following regions the cardia fundus body the gastr grug internally pylorus and the ementa so we'll start with the cardia the cardia is the portion that is uh adjacent to where the esophagus enters into the stomach it has some specific card CC glands that are there but cardia because it's closest to the heart uh we also have the fundus and the fundus is any Dome shaped top of an organ it's there's other organs that have a fundle portion or fundus portion and the fundus is this uh region that actually gas can accumulate inside this because gas Rises up and it's the highest part it's where belches kind of come from then there's the body which is the main portion of the stomach and that has two parts it has a lesser curve curvature which is a curve in the body of the stomach that's smaller and then a greater curvature which is a curve that's a little bit um bigger on the bottom of it uh we also have internally so if we were to now take a an imaginary scalpel and go Shing and just cut open it we take the front off in this coronal section we look inside we can see the these gastric rug these uh ridges that help to expand the stomach uh so the stomach can get bigger when we eat and then the very terminal part of the stomach is called the pyloris and the pyloris um uh when we take a look at another section where there's the pylorus that's been cut and then there's the dadum which is the next part of the small intestine right between we have this thickening of the of the inner circular layer of the muscular muscularis externa it's called the pyloric sphincter it contracts and its purposes to keep food from going from the dadum back into the stomach uh these two mesenteric structures one's called the Lesser momentum and one is called the greater momentum the Lesser momentum is a a mesentary that arises from the Lesser curvature of the stomach and then courses an attaches to the bottom of the liver um a word that means liver is hepato so if you think of hepat sites hepatitis anything of that nature it deals with liver now that's important because this lesser momentum really has two different components to it there's the pyloris part of the stomach which then goes there's that little derivation where the pyloric spincter is and then the dadum is next and so this lerum attaches to the dadum and the stomach and goes to the liver so anatomist love to name everything so we figure oh there's that little separation so we'll call that the hepat dadal ligament which is a part of the lerum and then this is the hpat gastric ligament hpat for liver gast for stomach and these two different uh ligaments are part of or aspects of the lerum um the Lesser mum also gives rise to this opening called the epiploic foramen and the epiploic foramin goes into this portion deep to the Lesser momentum called the Lesser sac and it's a blind-ended culdesac deep to the lerum and stomach the greater momentum is arising from the greater curvature of the body the stomach and then descends down to cover all the abdominal viscera it's called the guardian of the abdomen because within all this momentum which is connective tissue and a lot of adapost tissue there are also numerous lymph nodes and they have this really neat function of surrounding areas of infection or tumors and these lymphatic uh this some of this lymphatic tissue basically encompasses or encapsulates these areas of infection so doing abdominal surgery often the surgeon will look to see what the great Orum is doing as if it has migrated and surrounded a certain part of infection it's pretty neat so here we have an opening and there's the greater Orum and so you see it arising from the bottom or greater curvature of the stomach and it descends down and then it makes an apron it kind of Loops back up and ascends up and attaches all along the transverse colon let's do that again except in this sagittal cartoon where the stomach is shown by by the letter S and then TC stands for transverse colon um and there we have the greater momentum arising from the bottom of the stomach and it descends down and then loops and all the way up to the transverse colon makes this really big apron-like structure so small intestines that includes the following components there's dadum there's jum and there's ilium so let's take a look at the dadum first that dadum has four parts and they're called the first part second part third part fourth part did you like that came with a lot that's your tuition dollars at work there so the first part also has another name because anatomists love to give more than one name to these thousands of structures first part are superior second part descending third part transverse fourth part ascending so let's take a look at the first part the first part um is the part that a uh is associated with the end of the stomach so P stands for pyloris and then there in green is the first part of the dadum also called The Superior part because it's the highest area to add hurt to insult Radiologists also call it dadal cap or the dadal bulb because if we look at this upper G uh barium GI study where it's an x-ray but they've had the patient swallow barium and barium is a contrast which means it's dense and the x-rays don't go through it so everything you see in white is actually barium within the Lumen of your GI tract and that part of green is that first part of the dadum they call it dadal bulber cap because you see it makes like a cap on the top of the dadum um you know a couple of Parts about the first part of the dadum is it smooth walled take a look at the smoothness and the smoothness in contrast to the ruge that we see in the rest of the dadum it's also intra perianal where the rest of the second third and fourth parts of the dadum are behind the uh prodal perenium which is considered retr perenial uh it's also the first part is where dadal ulcers occur or primary place where they would occur now the second part of the dadum is this area outlined in green there it's called the descending part because as you see after the Superior part it descends down and it also is an area where the bile duct and the pancreatic duct uh put their products into the dadum the bile duct is going to be for bile and to emulsify fat and pancreatic duct for digestive enzymes those two ducks the bile and uh pancreatic duck come together and they enter into the second part of the dadum in this thing called the dermal papula or the ampula of v um that dark line represents uh a distinction between uh for gut and mid gut so the for gut is this embryonic part that is supplied by the Celiac trunk and the mid gut supplied by the superior mesenteric artery which we'll talk about later right after between the second and third parts of the dadum is where that separation occurs now the third part of the dadum is now distal to that it's called transverse because you see that this part kind of goes in a horizontal or transverse section I don't know if you can hear that but my children are screaming upstairs and jumping up and down be good times they might even come into this audio in a few minutes probably be screaming though now the third part of the dadum has the superior mesenteric artery and Superior mesenteric vein that Traverse over top so there we've got the superior mesic artery and there's a superior mesenteric vein veins always right arteries always left in this and that's one of the distinguishing features to this transverse part is a super mesenteric artery and vein course over top and now finally the fourth or ascending part as you can see that it goes up um gives rise to or then will then give rise to the J junim the next part of the small intestine and it's also where we have a this attachment called the ligament of trites that comes from the right crust of the diaphragm and attaches on right at that fourth part of the dadum where it becomes the junim and it's a it's a distinguishing feature that surgeons look for to determine where the dadum ends and the gunum begins suspensory ligament of trites sometimes called the uh dadal junal suspensory ligament now the jum the next part of the small intestine is deep to the greater Orum so let's take this greater Orum and go Shing and reflected up hey look there's all the small intestines that are there and the junam is located primarily in the upper left quadrant of the abdomen it starts at the ligament of trites and then stays in that upper right quadrant and within this jum there is numerous ple circular or known as circular folds and so if we were to take apart and open it up look at these circular folds and their whole purpose is to increase surface area for absorption so the dadum has this the pancreas dump these digestive enzymes that chemically break down carbohydrates to glucose um fats to fatty acids and glycerol proteins to amino acids and then they these circular folds or C circuli increased surface area for this absorption of all those nutrients into the blood so a lot of circular folds in the jum now the ilium is located primarily in the left right lower lower right quadrant pardon me lower right quadrant and it um you'll recognize that as you go along the small intestine there's fewer circular folds because there's less absorption that occurs because the majority of it happened more proximally in the small intestine now another thing that separates the ilum in these small intestines are these little tiny things in illustration I've rarely ever seen them grossly but they're there microscopically are these dense lymph noid uh nodules called pyus patches it's an aggregate a of lot of lymphatic tissue and it's there to help fight infection and primarily because you think the next part of the bowel is the colon and the colon has a ton of bacteria so to basically help make sure you don't infect yourself now our large intestines has the following components the seeum ascending transverse descending colon the sigmoid colum rectum and anus so we're going to start with the seeum first and the seeum is that first part it's a blind ended pouch which is what seeum means um at the bottom right quadrant of the abdomen and so there we have the ilum that empties into the seeum or the seeum receives contents of the ilum now on the bottom of the seeum is another blind-ended pouch called the vermiform appendix or just appendix it's a vdual structure organ doesn't do much except store lymphatic waste and um if it gets inflamed it's kind of a bummer so to find the append index in surface anatomy we find first the anterior superior iliac spine or Asis we find the emilus we make an imaginary line between the two in about a third of the way up between the Asis and the umbilicus there's this imaginary Point called MC Bernie's point that is the surface landmark of where the appendix and the seeum have their Junction ascending colon is this part that ascends in the right part of the abdomen and then at the very top is something called the hepatic flexure because the liver is Right Above It hepatic for liver it's also called the right colic flexure colic for colon the transverse colon arises from the right colic flexure and courses over to the splenic flexure where the spleen is located also known as your left colic flexure uh colic for colon then we have our descending colon from the left colic flexure all the way down to the bottom of the left lower quadrant you'll notice these little pouches that are called HRA and these out pouches are formed by this longitudinal muscle called the 10 Coline muscle and these Hoster give a very characteristic appearance to the large intestine our sigmoid Colin gets its name because sigmoid for S it makes this s shaped pattern as it goes into the rectum and this term rectum or rectus means straight that straight shot down um to the anus where the anal sphincters are internal anal sphincters smooth muscle where you don't control but as feces compacts down to the rectum the smooth muscle relaxes so the extrenal sphincter which is skeletal muscle voluntary control is the only thing that's stopping that feces from exiting because the next pathway in this is uh the toilet that's next and there is our GI tract in an overview