Liver Physiology

armando has to return biology and medicine videos please make sure to subscribe join the Foreman group for the latest videos please visit Facebook up - it again please like and here you can also ask questions answer questions and post some interesting things including your hours you can also change the quality settings to the highest one for better graphics in this video we're going to look at the functions of the liver liver physiology the liver has many many functions let's look at them one by one first of all it's it can synthesize amino acids the process one of the process is called transamination where we have an alpha keto acid which is an alpha carbon with the keto group and a carboxyl group which can get converted into an alpha amino acid where the alpha carbon has an amino group and a carboxyl group now the process as I mentioned is known as transamination an enzyme used is usually unknown as transaminase or amino transferase so let's look at one example one example is if we have glutamic acid here plus pyruvic acid with what enzyme will yield alpha ketoglutarate acid and also alanine alanine is the amino acid where the amino group is transferred from the glutamic acid into the pyruvic acid making alanine the enzyme used is known as alanine transaminase or alt note the transaminase the liver can also metabolize amino acid a process known as oxidative deamination essentially deaminate a molecule removes an amine group which is nh3 or two because it is an oxidation process the molecule itself is oxidized and so hydrogen is removed let's look at an example let's say we have glued L glutamic acid here with the amino group and this will be oxidized to a molecule and then be hydrated again when it gets hydrated the the previously L glutamic acid will liberate an ammonia group this ammonia group left the L blue to make a stood and so this process is known as the nation because the admin group left ammonia is important later on because it can enter the urea cycle we will look at it later on though but first another function the liver possesses is that it can synthesize proteins it can synthesize many many proteins one of the most important proteins is albumin actually 50% of the total protein the liver synthesizes is albumin albumin helps in maintaining the osmolarity and also transportation of various hormones the liver also produces synthesizes proteins for the immune system such as the c-reactive protein opsin in which helps for optimization of optimization of a pathogen and also it synthesizes plasma complement proteins c1 to c9 complement proteins are important for destroying a invading pathogen the liver also synthesizes various hormones and pro hormones such as insulin like growth factor IGF not IL f IL GF sorry its idea IG F is important for growth and also has anabolic effects the liver also produces thrombopoietin which is important in platelet production platelets is important for hemostasis for fixing up blood blood vessels the liver also produces another hormone known as angiotensinogen angiotensinogen is part of a big system known as a renin-angiotensin-aldosterone system this system helps regulate blood pressure the liver also citizens proteins their necess that are like that are clotting factors and inhibitors of coagulation so anticoagulants these are prothrombin fibrinogen and also antithrombin and alpha 2 microglobulin prothrombin and fibrinogen you may have heard from hemostasis in the repair of a damaged blood vessel for example now the liver also synthesizes plasma proteins that are important or carrier proteins that help carry substances or molecules from A to B such as from the liver to the kidney or from the or from the liver to the muscle for example so these are carrier proteins an example of carrier proteins is transferring transferring carries iron ions in the ferric acid forms Fe three-plus so transfer and carries iron iron atom ions around the body another one carrier protein is IGF insulin-like growth factor binding protein and this carries insulin-like growth factor-1 which if you remember is also produced by the liver and if you remember it shouldn't like growth factor one is important for growth and development now finally we can go back to the to another function the liver does is that is urea the production of urea so the liver produces urea what is urea well let's just draw the liver here so just recapping we know that amino acids can are can be made into proteins can synthesize proteins it can synthesize plasma proteins plasma proteins such as transferring and insulin like growth factor carrier protein which are both carrier proteins they carry proteins from A to B around the body amino acids can also be interconversion can enter into a conversion so it can become a pyruvate or it can become another sort of molecule but not amino acids alternatively amino acids can follow deamination remove 'men Timonium and so we have an accumulation of ammonia nucleic acid acids can also be metabolized to give off ammonia so what happens with this ammonia well ammonia nh3 can enter the urea cycle what's called the urea cycle to produce urea urea will then get expelled by the body and this is how um amine groups gets expelled n NH groups get expelled from the body through urea and they're usually excreted in urine so they go to the kidneys now possibly well one of the most important functions the liver has is the production of bile so bile production so the liver actually produces bile and secretes the ball where it gets stored in the gallbladder the gallbladder is underneath right underneath the liver and looks something like this and then we have a common bile duct where the gallbladder can essentially excrete or secrete out the bile into the intestines to help digest fats so let's look at this in a different diagram here we have the intestines and we have the pancreas right next to the intestines the small intestines this is the gallbladder is situated here and it essentially um secreted substances through the common bile duct which enters the intestines over here the gallbladder stores bile so what happens is when we eat fatty foods fatty foods will get digested by the stomach will enter the small intestines and will stimulate the small intestines to secrete a hormone known as C CK because the intestines cannot absorb these fatty substances just like that it needs the help of bile so it secretes the hormone CCK which will then stimulate the gallbladder to contract to then release the bile into the small intestines and to help emulsify the fats cover the fats so that the fats can be easily digested and absorbed by the small intestines now bile is made up of two main things it's made up of bile acids or salts and also bile pigments so bile acids and bile pigments let's firstly look at bile acids bile acids are amphiphilic steroids and they emulsifier ingested fats so that the fats can be easily digested and absorbed by the small intestines bile acids are amphiphilic steroids what does this mean well it means that if this was about acid it would have one side which is hydrophilic which means it loves water and the other side which is hydrophobic which means that it hates work so what does this mean well when we consume the lipid and when it's in small intestines the the bile acids will begin surrounding it where the hydrophobic regions will essentially cover the lipid and the hydrophilic regions will face the outside because the hydrophobic regions are scared of water and so they face inwards where is the hydrophilic region will face outwards and they will cover this lipid essentially emulsify it and create what's called a messy Lee's macelli's I don't know really how to pronounce it but essentially once they coat this lipid this can get easily digested and absorbed by the small intestines so some types of bile acids include colic acid Toro colic acid and deoxycholic acid those are some type of bile acid and bile salts so that was bile acids bile acids help emulsify fat while pigments are different to bile acids but they are also bile all together while pigments are actually the breakdown products of hemoglobin hemoglobin are the Centers of red blood cell so there's a break there the breakdown product of hemoglobin and these breakdown products these bowel pigments will then be secrete excreted out in feces and that is why we have the brown color in our feces so what do I mean by this so in the blood if there's a extravascular or intravascular hemolysis meaning destruction of red blood cells the outcome of this would be unconjugated bilirubin which is the product of destruction of red blood cells these unconjugated bilirubin will travel through the bloodstream bound to albumin which will then take it to the liver the hepatocytes of the liver so here we have now unconjugated bilirubin without the albumin unconjugated bilirubin will then be changed to conjugated bilirubin in the liver conjugated bilirubin is the bile pigment because it is the product of our breakdown of hemoglobin so this bile pigment this conjugated bilirubin will then travel through the Billy Ruby literary system through the bile duct into the intestines will get secreted into the intestines the conjugated bilirubin will then convert to euro bit urgent through bacterial protein lysis and about 90% of the urobilinogen will actually be excreted as feces so 90% of the bile pigments will be excreted as feces this euro Finnegan so what happened to the other 10% well the other 10% will be reabsorbed through the portal vein where it will then enter back into the liver if you know what the portal vein is so this Yerba digit will be in the liver and will then travel back into the bloodstream towards the kidneys where this 10% of your opinion will be excreted as you're on so essentially bile has two things is made up of two things bile acids or bowel salts and also by all pigments so about acids and bile pigments while acids are to help in digestion of fat but pigments are the breakdown products of red blood cells yep like your religion or conjugated bilirubin which then it gets excreted by the body as feces mainly hope that'll make sense now the other function the liver does is that it also performs carbohydrate metabolism very important you can also watch this on my bio chemistry videos but we'll just look at an overall picture here so the liver has a major role in controlling carbohydrate metabolism and so blood glucose levels as well so for example after we eat glucose will be get absorbed by the liver will get converted to glucose 6-phosphate take glucose 1-1 phosphate and then UDP glucose and then it will get converted to glycogen this whole process is known as glycol Genesis the synthesis of glycogen so glycan Genesis would happen if blood glucose levels are high if blood glucose levels are low glycogen will be broken down to bits of glucose 1-phosphate which will then convert to glucose 6-phosphate and then to so that glucose can be released into the blood on to increase blood glucose levels and this process is called glycogenolysis also glucose can convert through a series of reactions to pyruvate and produce ATP in the reaction if blood glucose levels are low and glycogen levels are low as well amino acids and also up fats for example can be converted to pyruvate which then will go through a process known as gluconeogenesis to produce more glucose the opposite of gluconeogenesis is collect collossus so hope you can see from this diagram that the liver not only has many functions such as producing bile but also in carbohydrate metabolism as well as other macromolecules such as lipid metabolism the liver actually produces a lot of lipoproteins lipoproteins as the name suggests is lipids and proteins but mainly lipids which travel around the body transporting lipids and proteins the liver also synthesizes cholesterol phospholipids phospholipids are our main part of lipoproteins phospholipids essentially make up most of the cell membranes we have our cholesterol is important for the body from in many in many fun in many respects if there's too much cholesterol however the body will secrete it either in bile or cliffs will be converted into bile acids because they have similar structure and then it'll be secreted in the intestines and be excreted as feces hope this video made sense thank you

Channel: Armando Hasudungan

Views: 604,042

Keywords: liver physiology, anatomy, Physiology (Field Of Study), hepatology, hepatocyte, bile system, biliary system, transamination, what does the liver produce, synthesize, synthesis, urea cycel, function, functions, summary, carrier proteins, plasma proteins, bile acids, bile pigments, what is, metabolism, hormones of the liver

Id: L61Z2uV-jOw

Length: 14min 55sec (895 seconds)

Published: Mon Mar 25 2013