Flashcards in The Liver and Gallbladder Deck (22):
Where does the majority of the blood supply tot he liver come from?
hepatic portal vein
What can the liver do to fructose and galactose?
convert to glucose
What is transamination?
transfer of an amino group to a keto acid
What is deamination?
removal of an amine group (often to form something such as alpha ketoglutarate which can enter the TCA cycle) and ammonium ion NH4+
What happens to the ammonia produced by gut bacteria or deamination?
converted to ammonium (NH4+) and then converted to urea in the liver
Where are most of the plasma proteins produced?
Name the main components of blood plasma
albumin, globulins, clotting factors and water
What does lipid metabolism involve?
breakdown of triacylglycerol to fatty acids and glycerol
What happens to the fatty acids produced by TG breakdown?
fatty acids are converted to acetyl CoA which enters respiration (TCA cycle)
What happens to the glycerol produced by TG breakdown?
glycerol is converted to glucose in gluconeogenesis
What is the effect of insulin on the liver?
Signals the 'fed-state' and causes the promotion of glycogenesis and suppresses gluconeogenesis and accelerates glycolysis by encouraging fatty acid synthesis
Outline the three phases of drug metabolism
Phase 1 - modification such as hydroxylation by cytochrome p450
Phase 2 - conjugation
Phase 3 - further modification or excretion
What are the 4 main things that the liver can store?
Glycogen, vitamins (A, D and B12), cholesterol and iron
Why is cholesterol important in our diet?
forms cell membranes, steroid hormones, skin and bile salts
How is iron stored in the liver?
Stores apoferritin as ferritin (reversible) and as haemosiderin (insoluble)
Describe the components of the biliary tree
The gall bladder is situated posteriorly to the liver and the liver has a hepatic duct, and the gallbladder has a cystic duct which combine to form the common bile duct. which the travels over the pancreas where it then joins the duodenum at the sphincter of oddi
Where is bile modified after secretion?
in the hepatocytes by cholangiocytes where bicarbonate is added
What stimulates gall bladder contraction to release bile?
CCK detects fatty acids in the lumen of the duodenum and causes gall bladder contraction and relaxation of sphincter of oddi
Describe the composition of bile
90% water but has bile salts, bilirubin, cholesterol, fatty acids, common ions and bicarbonate ions
Describe the origin, metabolism and excretion of bilirubin
Red blood cell breakdown in the spleen produces bilirubin which is then bound to albumin and transported in the blood and is conjugated to gluronate and egested in the faeces
What is jaundice?
yellowing of the skin and sclera due to an excess of bilirubin