Overview of the Digestive System

hi everybody dr mike here in this video i'm going to introduce to you the digestive system [Music] so very basically the digestive system takes in food and breaks this food down into its micronutrients and then absorbs these nutrients into the bloodstream for it to be dispersed through the tissues of the body to be used for energy or as building blocks now whatever remains gets defecated and leaves the body and this is this is the major function of the digestive tract now when i say digestive tract i'm also referring to that of the alimentary canal and that's the primary component of the digestive system i think that's worth writing down is the elementary canal now the elementary canal is this hollow muscular tube that goes from the mouth and snakes its way all the way through down to the anus now the thing is this this elementary canal whilst a muscular tube also has other layers to it that allow for it to have many different functions depending on what aspect of the tube we're referring to now in addition to the elementary canal another primary component of the digestive system are the accessory digestive structures now accessory digestive structures are not components of the elementary canal but they are accessory components and they often have ducts or tubes that lead into the elementary canal so the first thing i want to do is go through the various aspects of the elementary canal and i'm going to do this in blue so first thing is the mouth the mouth is the first aspect of the elementary canal then we go down to the pharynx which is the back of the throat then we go to the esophagus then the stomach then the small intestines and then we move through to the large intestines now the large intestines right at the very end which is the final structure of the elementary canal is that of the anus now these in blue they're all aspects of the elementary canal now the accessory components which we're going to highlight here in red these accessory components include those of the oral cavity which includes the tongue which includes teeth and includes salivary glands of which there's many kinds it also includes that of the pancreas which is which sits around about here and the liver which sits round about here now underneath the liver we've got something called the gallbladder so we've also got the gallbladder now what i might do is just put a little asterisk here and then i'll put an asterisk here for gall bladder and these are all various aspects of the accessory structures now what i want to talk about is the function of the digestive system so the function of the digestive system let's begin with that of ingestion so number one ingestion taking food in so eating let's say intake which is eating the second function we need to talk about is that of secretion so the digestive system actually secretes substances and these substances are enzymes and mucus enzymes and mucus now these enzymes can be digestive enzymes for example things that break down proteins fats or carbohydrates and the mucus is obviously an extremely important structure because we're going to have substances moving through this elementary canal there's going to be friction in this environment and we don't want to damage the cells of that tissue so mucus is also very important another important function of the digestive system is that of mixing in actual fact mixing and propulsion so the foodstuffs that we take in we need to mix mix mix it up and we also need to push it through the tract this process of mixing and pushing is termed peristalsis number four another function of the digestive system is that of digestion so we can't forget that primary role of digestion now importantly you've got both mechanical and chemical digestion mechanical and chemical now what's the difference between the two mechanical is physical digestion that's actually part of this mixing and propulsion process that's where we physically tear things apart so our teeth for example and our tongue allowed to break things apart that's mechanical digestion our stomach can throw things around that's mechanical digestion chemical digestion involves these enzymes that are being released or secreted from the digestive tract and again they're molecular scissors that chop up big carbohydrates big triglycerides and big proteins into their smaller components of glucose galactose fructose for example of fatty acids and glycerol or other amino acids respectively that's number four number five is out of absorption so once we've broken these things down we need to absorb them and they're actually absorbed into the blood stream well most of them are absorbed into the bloodstream some like fats are absorbed into the lymphatic system and different substances are absorbed at different areas of the tract so for example alcohol can be absorbed at the stomach but not much else you'll find the small intestines will be one of the primary sites for absorption when it comes to nutrients but the large intestines are a really important site for vitamins and water and electrolyte absorption okay all right that's number five number six which is the final one is that of excretion so number one is intake last one is going to be excretion and excretion is defecation and what we are excreting from the body obviously at the anus is going to be indigestible products or substances that we no longer require and that's the final stage of the functional processes of the digestive system so what we've gone through here first of all is we've broken the digestive system into the elementary canal and the accessory structures we'll be talking more about this in detail in future videos and all the different functions of the digestive system

Channel: Dr Matt & Dr Mike

Views: 198,364

Keywords: digestive, introduction, overview, summary, system, gastrointestinal, gastro, gut, git, stomach, intestines, digestion, absorption, defecation, ingestion, esophagus, colon, bowel

Id: Z4N0cgpgAMc

Length: 8min 6sec (486 seconds)

Published: Tue Jul 28 2020