physiology and pharmacology of the Liver Flashcards
what is a marker of liver function
albumin and PT time
low albumin is a sign of what
CHRONIC LIVER problems and malnutrition
what is hypoalbuminaemia also found in
hypercatabolic states (e.g. trauma with sepsis) and in diseases associated with an excessive loss (e.g. nephrotic syndrome, protein-losing enteropathy)
what does the liver do
STORES
fat soluble vitamins - ADEK and B12
copper and iron
glycogen
DEGRADES
insulin, steroid hormones, ADH and glucagon
activates vitamin D to 25(OH)D
where is albumin made and what does it do
in the liver
regulates the oncotic pressure of blood and transports water-insoluble substances such as bilirubin, hormones, fatty acids and drugs
what cagoulation factors does the liver produce
factor II, VII, IX and X
protein C and S
what are the protective liver cells
Kupffer
what do Kupffer cells do
digest/destroy cellular debris and invading bacteria
what happens to bile between meals
stored and conc in gall bladder
what is the sphincter of Oddi like between meals
closed
during a meal what happens to gall bladder
chyme in duodenum stimulates gall bladder smooth muscle to contract via CCK and vagal impulses
during a meal what is sphincter of Oddi like
opens via CCK
what happens to bile during meal
spurts into duodenum via cystic duct and common bile duct
what does bile participate in
the digestion and absorption of fats
what is the composition bile
bile acids cholic and chenodeoxycholic acids form bile salts with Na and K
bilirubin
IgA
cholesterol
phospholipids and lipids
what is another name for gallstones
cholelithiasis
what is the best surgery for symptomatic gallstones
laparoscopic cholecystectomy
what drug can be given for gallstones
ursodeoxycholic acid
what are the indications for ursodeoxycholic acid
small or mediums sized stones unimpaired gall bladder function
what is biliary colic
pain due to gallstone temporarily blocking the bile duct
what are the analgesic options for biliary colic
morphine buprenorphine or pethidine
why is morphine preferred
Although morphine causes sphincter of Oddi to contract more it is a better analgesia and not contraindicated
what drugs would you use to relive biliary spasm
atropine and GTN
what happens to 5% of bile salts entering duodenum
lost in faeces
what happens to most of the bile salts entering duodenum
reabsorbed in the terminal ileum and undergo enterohepatic recycling
explain bile acid sequestrant mechanism
Trap the bile salts in the intestine, increasing their excretion resulting in more cholesterol to be converted to bile salts by interrupting enterohepatic recycling.
Prevent the reabsorption of bile salts.
The fall in hepatocyte cholesterol concentration causes compensatory increase in HMG CoA reductase activity and the number of LDL receptors (main mechanism in which they lower cholesterol).
adverse effects of bile acid sequestrants
are confined to the gut, because the resins are not absorbed; these effects include bloating, abdominal discomfort, diarrhoea and constipation.
bile acid sequestrates are use in
hyperlipidaemia and choelstatic jaundice
what size of dose required
large
bile acid sequestrates can cause deficient of what
fat soluble vitamins
what drugs have unchanged activity during metabolism
diazepam to nordiazepam
compare aspirin and its metabolites activity
aspirin - anti inflammatory and anti platelet
metabolite - anti inflammatory
what is the name of aspirins metabolite
salicylate acid
name some reactions that happen in phase 1 of drug metabolism in liver
oxidation hydrolysis reduction
name some reactions that happen in phase 2 of drug metabolism in liver
conjugation
what do the CYP450 family of monooxygenases do
mediate oxidation reactions (phase 1) of many lipid soluble drugs in the liver
what is hepatic encephalopathy
the occurrence of confusion, altered level of consciousness, and coma as a result of liver failure
explain hepatic encephalopathy pathophysiology
- liver fails - nitrogenous waste builds up as ammonia in the circulation - passes t brain - cleared by astrocytes - excess glutamine causes an osmotic imbalance and a shift of fluid into these cells - cerebral oedema
hepatic encephalopathy - treatment
lactulose
lactulose is what type of laxative
osmotic
lactulose effects
retain water - inc bulk - inc peristalsis
antibiotics used in hepatic encephalopathy
neomycin rifaximin
