Liver Function Flashcards
What is the name given to macrophages with the the sinusoidal spaces in the liver?
Kuppfer cells
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?
Alkali
What do hepatocytes secrete?
Hepatic bile Lipids and phospholipids Cholestrol IgA Bilirubin
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... Conjugate Glucoronide
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)
Bilirubin
Adrenal corticosteroids
What are the 4 main plasma proteins produced by the liver?
Albumin
Alpha globulins
Beta globulins
Theta globulins
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?
Albumin
What promotes the production of albumin?
Insulin
How much albumin is produced a day?
14g
Give an example of a drug that albumin is good at transportin
Asprin
How is iron transported around the body?
Transported as ferric ion Fe3+ bound to transferrin
How is copper transported around the body?
Ceruloplasmin
What are the 5 types of lipoproteins?
Chylomicrons VLDL LDL IDL HDL
Where do chylomicrons originate?
Intestine
Where do VLDLs originate?
Liver
Where do IDLs originate?
VLDLs
Where do LDLs originate?
VLDLs/IDLs/Liver
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?
LDL precursor
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?
Vitamin A
Vitamin D
Vitamin B12
What are the main sites of cholesterol synthesis?
Liver
Also; intestine, adrenal cortex and gonads
What is the rate limiting enzyme in the synthesis of cholesterol?
HMG-CoA reductase
What are the products of cholesterol?
Vitamin D
Steroid hormones - Corticosteroids, androgens and estrogens
Bile salts
What is the level of cholesterol at which there is a risk of atheroma formation?
4.1mmol/L
