Flashcards in Liver Function Deck (36):
What is the name given to macrophages with the the sinusoidal spaces in the liver?
Where is bile stored?
Gallbladder inbetween meals
How is bile released?
When there is chyme present in the duodenum, cholecystikinin is released which opens the sphincter of oddi releasing bile into the duodenum
Is bile acidic or alkali?
What do hepatocytes secrete?
Lipids and phospholipids
What is the precursor of bilirubin?
Porphyrin component of haemoglobin
What happens to urine and faeces if bilirubin is present?
Urine darkens and stools become pale
How can metabolism affect drugs?
Can convert drugs into polar metabolites so they can be exrcreted via the renal system
Convert drugs so that they become active metabolites
Convert drugs to metabolites with a different mechanism of action
What are the two main phases of drug metabolism?
Phase 1 - Oxidation, Reduction, Hydrolysis
Phase 2 - Conjugation
Give an example of the two phases of drug metabolism?
Drug = Asprin
Phase 1 converts it to...
Derivative = Salicylic acid
Phase 2 converts it to...
Describe the monooxygenase cycle.
Drug enters as drug substrate (RH)
Oxygen provides two atoms of oxygen
One of which is added to the substrate to yield the hydroxyl product (ROH)
The other combines with protons to form H2O
Give an example of two substances that are subject to phase 2 reactions in the liver (Glucoronidation)
What are the 4 main plasma proteins produced by the liver?
What do plasma proteins do?
Maintain osmotic pressure
Transportic hydrophobic substances
Act as pH buffers
They have enzymatic and immune activity
What is the most common plasma protein?
What promotes the production of albumin?
How much albumin is produced a day?
Give an example of a drug that albumin is good at transportin
How is iron transported around the body?
Transported as ferric ion Fe3+ bound to transferrin
How is copper transported around the body?
What are the 5 types of lipoproteins?
Where do chylomicrons originate?
Where do VLDLs originate?
Where do IDLs originate?
Where do LDLs originate?
Where do HDLs originate?
Intestine and liver
What do chylomicrons do?
Transport of exogenous fat to liver
What do VLDLs do?
Transport of endogenous fat to peripheral cells
What do IDLs do?
What do LDLs do?
Transport cholesterol to peripheral tissues
What do HDLs do?
Reverse cholesterol transport
Removes excess cholesterol from cells
So that it can be transported back to liver to be synthesised
Which vitamins does the liver store?
What are the main sites of cholesterol synthesis?
Also; intestine, adrenal cortex and gonads
What is the rate limiting enzyme in the synthesis of cholesterol?
What are the products of cholesterol?
Steroid hormones - Corticosteroids, androgens and estrogens