so today we're going to be taking a look at the digestive system and one of the main reasons we're going to do this is because every single person has had a de Geste a system dysfunction throughout their lives whether it's a small little stomachache indigestion or even life-threatening conditions that require surgery and if all else fails we want to know what happens to this lovely pastry when we ingest it and it goes through this wonderful tube that we're going to talk about here so let's get to it [Music] so the first concept we want to
address with the digestive system is simply this this thing is one long tube so the first part of the tube we want to show is the esophagus it's beginning of the tube and then this transitions into the stomach and then the stomach becomes the small intestine the small intestine is actually the longest portion of the whole digestive system and the whole system can be up to 23 to 29 feet in a cadaver 16 to 23 feet in a living person and that's because in a living person the smooth muscle in the two is actually contracting
and therefore shortening the two the last part of the digestive system is the large intestine here and this is shorter than with small intestines we've already addressed but it's wider now what's amazing to think is that this thing actually coils up and your abdominal cavity actually fits in there and we're gonna address that issue but first we're gonna go back to the beginning and start with where we first ingest food and see what happens there so now that we've established that this is one long tube now we got to go back to the beginning and
the beginning is simply ingestion we got to put something into our mouth and ingestion and putting something into our mouth is the beginning of actually digesting food we do this mechanically by chewing and manipulating with the tongue we also do it with saliva we have a couple of salivary glands the parotid glands the submandibular glands and even the sublingual glands a lot of you've probably experienced that aching that sometimes when you put like a sour piece of candy or food in your mouth you can feel that aching from the salivary gland actually pushing its secretions
into the mouth and this helps soften the food also even has some digestive enzymes to help start the digestive process once we've done all the chewing and salivating we then move it back to the throat the fancy-pants name for the throat is called the pharynx in anatomy once we get into the pharynx we move to the esophagus and the esophagus essentially lies right through here and it's posterior to the sternum and actually posterior to the trachea which is the windpipe which I'm going to show you right now as we take a look at the guts
that we had actually across the table a little bit earlier now we've somewhat oriented this about how it would be in the human body you can kind of see lower down here we've called up the small intestine here the large intestine is this picture frame wrapping around here a little bit higher you can see the stomach here but again the beginning is this region and I just mentioned the trachea the trachea is not part of the system we'll talk about it in a later video so I'm going to reflect it away and underneath you can
see the food tube or the esophagus now again each segment of the tube has a specific function we want to address these as we move through the tube in sequence the esophagus is pretty simple it secretes mucus which helps kind of lubricate itself so food can slide and glide down it also just as simply this transport tube transports food from the pharynx again which was a throat down into the stomach and again just site you know for those of you who've ever had heartburn you can blame the esophagus you can feel that burning sensation that
has acid coming up from the stomach and again you can see that relationship coming down here on the cadaver where we have the esophagus just becoming this the stomach the stomach as I already mentioned produces hydrochloric acid it also will literally churn and move the food and mix it together now as far as location if I step back you can again this is about where it would be located up in the left upper quadrant or upper left quadrant here part of its tucked underneath the ribs sometimes even the liver will cover up this region of
the stomach as well but one thing that's really cool about the stomach is this thing can stretch out like crazy do you guys have that big you know binge eating during say like Thanksgiving dinner this thing can stretch out and one things that we can show for this is another stomach over here now this stomach you can see we've detected away and opening it up you can see these amazing folds called gastric Ruby just literally translates to stomach folds gastric means stomach roogie means fold and these things allow for stretching for that little food baby
you might get on Thanksgiving dinner so moving on from the esophagus we go into the small intestine small intestine is broken down into three segments let's start with the names duodenum jejunum and ileum I had a friend who always said DJ Isis that was how he always remembered the order from duodenum jejunum and ileum now if you want to say duodenum or duodenum that's fine but we typically I'll say duodenum here now on the cadaver here or this segment of the gut tube that we mentioned earlier I'm gonna reflect the large intestine just a way
so you can see the very beginning of the small intestine which I mentioned was the duodenum now the duodenum is still going to take part in digestion just like the stomach was digesting things by mixing things around with the acid and churning the duodenum has some relationships with what we call accessory digestive system organs three of them that you've heard about the liver the gallbladder in the pancreas let's start with the liver now the liver is tucked up in the right upper quadrant this thing is the second largest organ in the human body just second
to the skin and this thing has so many functions it's an amazing organ but we're only going to focus on one and that is simply produces bile and bile is a really important substance to break down fat you can't talk about the liver without talking about the gallbladder the gallbladder is a little storage organ a little storage facility if you will for extra bile and that little organs tucked up under the liver or just inferior to the liver so say you have a nice fatty milk and you need a little extra bile that gallbladder can
squeeze some of its stored bile along with the liver squeezing out some bile and it dumps it into again the duodenum before we complete this digestive story we have to the pancreas pancreas it's really awesome organ as well it's involved in the endocrine system and insulin but we're gonna focus on its exocrine function or what we call its digestive system function because this thing produces all of these things called digestive enzymes or pancreatic enzymes and these enzymes are gonna break down carbs proteins and all the things you need to break down because we can't absorb
anything into the bloodstream until it's broken down into it's a little smallest components and just real quick the pancreas is location this thing is actually posterior to the stomach remember we mentioned the stomach is right up here kind of covered up by the left side of the ribcage even projection of the middle but the pancreas kind of dives over to the left side it kind of almost looks like it's shaped like a little bit of a gun or sometimes people might think it looks like a tongue even but you guys can decide what you think
it looks like regardless this thing is really important with the liver with the gallbladder to put all these secretions into the duodenum and the duodenum again will then have its final digestion of these foods and once we move from the duodenum or the duodenum we become the jejunum and you can see this length the majority of the small intestine is the jejunum and the ileum there's not like some specific line where it says okay this is the ileum this is the genome but the Oleum is the last part and I'm essentially in the ileum here
and I'm moving around coiling around and why is this thing so long that's a really important question the reason is is we need as much length in surface area to absorb as many nutrients as we possibly can now on this cadaver you can't see how it's attached to the posterior abdominal wall but on this other cadaver that we're gonna show here you can see all of this yellowy tissue and in all this tissue there you're going to see tons and tons of blood vessels and these blood vessels are simply for absorbing all of those nutrients
out of the small intestine so hopefully that gives you an idea on the small intestines function the first part of the duodenum or duodenum is gonna finish digesting digesting with the help of the liver gallbladder and pancreas and the jejunum and the ileum is just gonna suck all those nutrients in now coming back to this cadaver or this gut tube on the actual tray here let's reorient you again this was the end of the ileum the ileum transitions into the large intestine and the first part of the large intestine is called the cecum so going
from ileum to cecum you can see the difference here the cecum is a much larger sac or even the large intestine has a larger diameter and the ileum and cecum they have a valve in between crazy name called the ileocecal valve this stops one-way this creates one-way flow ER is how I should say that it stops any food or at this point feces or stool because we're no longer absorbing at this point from going back into the small intestine so the large bowel I just want to step back and kind of show you how this
would be oriented here essentially is starts here on the lower part of the right side of the abdomen or right lower quadrant here and it ascends up comes across down and then kind of squiggles out it kind of creates this picture frame how I kind of think of it as at least around the small intestine which is the central abdomen here so coming back again to our tray here moving up they just simply call this the a sending colon coming across this is the transverse colon moving down this is the descending colon now in a
different cut hour you can actually see that this would kind of squiggle out and we'd call that the sigmoid colon and that hooks up to the rectum and eventually the anus but what do all those things do as far as the a sending comb the transverse colon the descending colon the large intestine is simply the storage organ where it's going to actually store fecal matter for when we actually eventually hopefully get it to the toilet the other is it absorbs the last part of water insults so those are some important things that you want to
actually keep in mind and there's a couple of features I want to move and show you before we leave this dissection here one on the cecum you can't actually see what normally comes off there's normally this little worm-like structure that comes off called an appendix I'll be able to show you that on this cadaver where it's this little small worm-like structure they actually call it the vermiform appendix because verbal form actually means worm-like and if I move back to the small intestine I want to show you something that's really cool as well if I we've
opened this up and you can actually see these little folds right here they call them circular folds remember I asked the question why is this thing so long and the small intestine is so long because it's got to absorb so many nutrients another thing to help absorb nutrients or to increase surface area is these folds and they allow for the absorption of even more nutrients okay hopefully you guys enjoyed that video be sure to continue to leave us some requests on future videos we're trying our best to keep up with all the requests but we'd
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