认识胃肠道！

have you ever realized that it your deepest most inner core you're not really you well think about it the minute you eat something and swallow it and it passes in through your gastrointestinal tract that's the external environment that food that you just took in was a part of the outside world and the tract that it's gonna follow in through from your mouth till the point that you expel it in the bathroom is actually not you that's the external environment how weird is that so in this video we're gonna do an overview of the gastrointestinal tract I'll talk about each of the individual parts and what their main overall functions are and then in subsequent videos I'll go through each of these individual parts and give a more detailed explanation of how they do what they do alright so starting off of course the first place our food is ever gonna go to is our mouth or the oral cavity the main functions that we have achieved in the mouth include chewing the Morse elation of food also very important is hydrolysis as you might recall from biochemistry hydrolysis is just the enzymatic digestion or the enzymatic breakdown where chewing is the physical breakdown hydrolysis is the enzyme assisted breakdown of food and so as we break down food the goal here is to make what's called a bolus just a sphere of digested food that can then be swallowed and passed on into our next structure and so after we swallow the food where do you think it goes this guy right here and that's the e so Vegas the esophagus and this I think is one of the more boring parts of the GI tract because all we do here is just propel our bolus we just pass it on down to the next guy we don't really even do anything to it kind of boring but the next guy is a little more exciting now we get to the stomach a lot of action going on in the stomach one of my favorite parts of the GI tract the stomach is its responsible for multiple things including churning which is a lot like chewing except that there are sort of more dimensions of contraction affecting the food and breaking it down we also have hydrolysis going on here the enzyme assisted breakdown of food in addition to that you can store food in your stomach if it's not time to pass it on to the next component of your GI tract and the overall goal here is to make what's called chyme so we take our bolus and we sort of melted down per se into this more fluid type of substance that we can pass on to our intestines so we're moving on now to our intestines so starting from about this point right here we get our duodenum and then this kind of you know circulates around here and then we end up at this point everything in between I'll draw it way out here I'm just gonna group together for right now as the small intestine the small intestine and there are three parts to this and we'll talk about that in a subsequent video but the main functions that we achieve here are hydrolysis and also the absorption of nutrients and notice this is kind of the first part of your GI tract that you're finally taking in some of the breakdown food products and using them for nutrition to make other products in your body great so now that we've gone through the small intestine what do you think shows up next so starting from after the small intestine ended all the way through this lined structure right here we are gonna be passing through the large intestine the large intestine do you guys remember the other name for the large intestine it starts with a C if you said : absolutely right so the colon is also one of the more boring parts of the GI tract so really all we have going on here is absorption but not of nutrients per se more like things like water or ions or vitamin K just things like that are absorbed in the large intestine so not a very high yield place for acquiring nutrients and then after that we're gonna pass food on to this structure here and this is called the rectum the rectum kind of like the stomach of the GI tract the rectum serves for storage we hold on to our processed food if we can call it that anymore at this point and it's held there until we deem it an appropriate time to expel the food and so when it's time to expel the food it'll come out through the anus through expulsion expulsion so those are all the key components of our gastrointestinal tract there are some other accessory organs that are involved here in digestion and we'll all have videos to talk about them as well those include things like the liver the gallbladder the pancreas and those will come up in subsequent videos