Physiology & Pharmacology of liver Flashcards
What are the main metabolic functions of the liver?
- Carb metabolism- Gluconeogenesis, glycogenesis, glycogenolysis
- Fat metabolism- lipoproteins, cholesterol & triglycerides, phsopholipids, ketogenesis
- Protein metabolism- deamination of amino acids, convert ammonia to urea
What are the main hormonal functions of the liver?
Breaks down
- Insulin
- Steroid hormones
- Glucagon
- ADH
Normal thyproid function dependent on hepatic formation of more active form of T3 than T4
What is the liver responsible for storing?
- Vitamins- A,B12,E,D,K
- Copper
- Iron
- Glycogen
Also important for coagulation factors like- Factor II, VII, IX, X. Protein C & S
Synthesise plama proteins
The liver is protected by liver phagocytes known as _ cells. These cells digest cellular debris/invading pathogens.
Does the liver play a role in detoxification?
Kupffer cells
Yes- of drugs/alcohol
Summarise the various functions of the liver
- Metabolise carbs, fats, proteins
- Hormonal degradation/regulation
- Vitamin and coagulation factors production
- Albumin production
- Protection
- Detoxification
Between meals, where is bile stored? Which sphincter allows the bile to stay there?
Gall bladder
Sphincter of Oddi remains closed
During meals, the producton of what chemical stimulates the release of bile from the gall bladder?
Cholecystokinin
- Chyme in duodenum
- Stimulates gall bladder sm to contract
- Sphincter of Oddi opnes (via CCK)
- Bile relased into duodenum via common bile duct and cystic duct.
Bile is a secretion of what two cell types?
- Hepatocytes
- Bile duct cells- Cholangiocytes.
What are the two main acid types found in bile?
- Cholic acid
- Chenodeoxycholic acid
Other components of bile?
- Water & electrolytes
- Lipids
- Bilirubin
- Cholesterol
- IgA
Bilirubin is responsible for the breakdown of _. When in excess it can cause _.
Haemoglobin
Jaundice
What is cholellithiasis? Give a brief descrption of its pathology.
Formation of gallstones. Body’s only natural way of removing cholesterol is by its uptake and excretion by bile.
However when Cholesterol levels are excessive, they can no longer remain in bile solution and crystalise out of it. This accompanied by hypomobility of the gall bladder and mucus hypersecretion leads to gall stones.
What is enterohepatic recylcing?
Once bile is released into the circulation, the majority (95%) of the salts are actively reabsorped by the terminal ileum and transported back via to the HPV to the liver, and re-excreted in bile.
What is the action of bile acid sequestrians or resins? Give three exampeles. (hint cole)
They bind to bile salts, preventing their reabsorption.
- Colesevalam
- Colestipol
- Colestyramine
How do bile acids sequestrians promote indirect cholesterol reduction? what diseases are they used in?
Promote hepatic conversion of cholesterol to bile. Resultant increase in LDL receptor expression in liver cells. increases clearance of LDL cholesterol from plasma.
Used in- Hyperlipideamia, Cholestatic jaundice
