wk 6 1 Physiology Pharmacology of Liver Flashcards
metabolic functions of liver can be divided into carbohydrate metabolism, fat metabolism/synthesis, and protein metabolism, what does each cover
carbo
- gluconeogenesis
- glycogenolysis
- glycogenesis
fat metabolism and synthesis of
- lipoproteins
- cholesterol/triglycerides
- phospholipids
- ketogenesis (starvation)
protein
- deamination of amino acids
- ammonia - urea conversion
in hormone metabolism, the liver is the major site of degredation for 4
insulin
steroid hormones
glucagon
ADH
which plasma protein in synthesised in liver
albumin
5 vitamins, 2 metals and one carbohydrate is stored in liver, what are else
vits
- Vit A, B12, E,D, K
metals
-Copper, Iron
carbo
- Glycogen
what are kupffer cells, what do they do
liver phagocytes
destroy cellular debris (RBCs) and invading bacteria
what happens to bile between meals
stored - sphincter of oddi closed
what happens to bile during a meal
chyme in stomach stimulates gall bladder smooth muscle to contract ( CCK and vagal impulses)
sphincter of oddi opens (CCK)
bile enters duodenum via cystic and common bile ducts
bile is used for the
digestion and absorption of fats
2 types of acid bile adds
cholic and chenodeoxycholic acids
which immunoglobulin is found in bile
IgA
symptomatic stones in biliary system are treated by
laparoscopic cholecystectomy
if the stone is not impairing the gall bladder function, what may be given instead
Ursodeoxycholic acid
biliary colics is when the gallstone blocks the tract, v painful. Morphine causes contraction of sphincter of Oddi, so what may be given instead
Buprenorphine
pethidine
2 drugs that may be given to relieve biliary spasm
GTN
atropine
enterohepatic recycling prevents most of the bile salts from being excreted, what is the type of transport used
active transport via Na+ transporters
SLCOA2 + SLCOA1
how does bile acid sequestrants such as Colesevelam, Colestipol, and Colestyramine work
bind to bile acids and prevent reabsorption through the enterohepatic recycling systen
when would colesevelam be given
lowes plasma cholesterol
in hyperlipidemia, cholestatic jaundice
explain how colestipol indirectly lowers cholesterol
promote hepatic conversion of cholesterol into bile acids
increases LDL-receptor activity, and so increases clearance from plasma
what is the problems with bile acid sequestranrs (colsevelam, Colestipol, Colestyramine) 3
unplatable, inconvient - large doses
GI side effects
fat soluble vitamin defiency
most of the time drug metabolism is to either make the drug more polar (not readily absorbed by kidneys, can be excreted) or into a form that is pharmalogically less active. However they may also convert from inactive - active, have unchanged activity, or possess a different action. Give an example of eac hq
inactive to active - codeine to morphine
unchanged - diazepam - nordiazepam
different - aspirin (antiplatelet) - salicylic acid (no platelet activity)
drug metabolism is usually in two sequential phases. what is each
phase I - oxidation, reduction and hydrolysis (more polar)
phase II - conjugation
which protein mediates the oxidation reactions observed in phase in (in lipid soluble drugs)
Haem proteins
in liver failure, what rises which leads to a coma
blood NH3 levels (cannot detoxify into urea and so cannot be removed)
2 therapeutic options for Hepatic Encephalopathy
Lactulose (reduces pH)
Antibiotics - Neomycin, Rifaxmin (suppress colonc flora and inhibits ammonia generation)
