Lecture 6 - Liver and Bile Flashcards
Functions of the liver
- process nutrients
- synthetic fxn
- protection
Glucose processing in the liver
- glycogenesis = storage via making of glycogen
- gluconeogenesis = making new glucose from propionate, lactate, AA
- glycogenolysis = breaking down glycogen
- FA synthesis
Fat metabolism in the liver
- Synthesize triglycerides from:
1. FA syn. in the liver
2. FA mobilized from adipose tissue - Lipoprotein synthesis = machinery for triglyceride transport
Protein metabolism in the liver
- ammonia detoxification; urea and glutamine production
- non-essential AA synthesis
Phenylketonuria (PKU)
caused by lack of enzyme that converts phenylalanine to tyrosine
Synthetic fxn of the liver
- plasma protein synthesis
1. albumin for transport of NEFA and creates osmotic pressure of plasma to keep H2O in blood
2. fibrinogen, prothrombin for blood clotting
3. transferrin for iron transport
Protection fxn of the liver
- prevent bacteremia via Kuppfer cells wthat line the sinusoids and are responsible for clearing infections
- breakdown of toxins and hormones aka detoxifying and excreting in bile
Where does liver damage occur
stellate cells produce fibrous scar tissue to wall off damaged areas to protect the liver
- a lot of fibrous scarring = sclerosis or cirrhosis
Jaundice
- bilirubin is not excreted by hepatocytes in the liver
- yellow pigment; brown in feces
3 causes of jaundice
- haemolytic = too much lysis of RBC
- hepatic = liver is damaged and not fxning properly
- post-hepatic = bile trapped in gall bladder
2 sources of blood to liver
- oxygenated via hepatic artery from heart
- deoxygenated via portal vein
portal triad
portal vein, hepatic artery, bile duct
hepatocytes
- heterogenous = different roles based on where in the sinosoid they are; metabolism, detoxification, protein synthesis
space of disse
allows molecules through for hepatocytes to grab
Kupffer cells
- line the hepatic sinusoids
- remove bacteria, immune complexes, and damaged erythrocytes
What are bile acids synthesized from?
cholesterol
primary bile acids
cholic acid and chenodeoxycholic acid (pk = 6)
secondary bile acids
deoxycholic acid and litocholic acid
What is added to secondary bile acids to make them conjugated bile acids
- glycine and taurine
