Flashcards
Liver 2
Cards in this deck (11)
- 1Describe the role of hepatocytes in regulation of blood glucose levels- first-pass metabolism
- carbohydrate synthesis and storage
- glycogenesis -> glycogenolysis
- has glucose-6-phosphatase allows glucose -> blood stream (removes charge) - not in muscle -> pyruvate
- insulin and glucagon act antagonistically on the liver - 2How does insulin affect hepatocytes?- activation of the insulin (RTK) receptor on the liver
- dephos key enzymes in glycolysis and gluconeogenesis
- inhibits some enzymes
- promotes glycogenesis and lipogenesis - 3How does glucagon affect hepatocytes?-activation of Gs GCPR receptor on liver
-> increased cAMP, increased PKA
- phosphorylation to increase activity of key enzymes involved in glycolysis and gluconeogenesis as well as glucose-6-phosphatase
- inhibits glycogen and lipid production - 4Describe amino acid catabolism and ammonia detoxification- a.a must be used or degraded
- deamination -> a-keto acids (TCA) + NH3
- NH3 (toxic) -> urea cycle (hepatocytes) -> urea
- urea cycle is energy-dependent
- secreted by kidney as urea
- deficiencies in key enzymes - toxic - 5Name the most important proteins synthesised by the liver for export- major plasma proteins e.g. albumin
- haemostasis and fibrinolysis (blood clotting)
- binding and carrying proteins e.g. transferrin
- prohormones - angiotensinogen
- lipoproteins- apolipoprotein - 6Describe the role of the liver in cholesterol metabolism- enterocytes esterify lipid components into chylomicrons -> lymph -> blood
-> lipases -> epithelia ect.
-> remnant cms are synthesised to cholesterol for storage
-> LDL -> adipose tissue (HDL -> liver)
Cholestel (liver) -> bile acids - 7Describe the general process of cholesterol synthesis and how this process can be regulated as well as the importance of itAcetyl CoA -> cholesterol
Statins can inhibit an enzyme involved in synthesis
Cholesterol also inhibits the same enzyme
. membrane fluidity
. steroid hormones
. bile acids - 8Describe the general structure and importance of bile- provides excretory route for solutes not excreted by kidney
- bile salts + acid required for lipid digestion
- bile acid - cholic acid
- conjugated to glycine or taurine = salt
- Bile acid- lipid absorption mixed micelle - 9Summarise the secretion of bile- 90% recirc 10% de novo bile acid (active) secretion from hepatocytes
- passive movement ofwater trough tight junctions
- secretion of water HCO3- rich by cholangiocytes
- gall bladder - concentrates salts - movement of water and HC03 isotonic - 10Summarize the breakdown of bilirubin- tissue macrophage system - haemoglbin -> haem -> biliverdin -> bilirubin
- blood -> albumin-bilirubin
- hepatocyte -> bilirubin -> bilirubin-glucoronide
- small intestine -> microbial enzymes
. excreted by the kidney or in faeces - 11What is jaindce and explain what can cause itjaundice is the build up of bilirubin in the blood plasma
- haemolysis
- can't take up bilirubin into the hepatocyte
- can't conjugate it - def. in glucuronyl transferase
- csn't trasnfer it to the bile canalicullu
blockage of biliary ducts
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- Physiology Flashcards on Liver 2, created by Charlotte Pedley on 12/12/2018.
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- Charlotte Pedley
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