liver physiology Flashcards
how much bile is secreted per day?
250ml-1000ml
what are the functions of ITO cells?
secretion of the extracellular matrix of the space of disse. storage of fat and fat soluble vitamins.
name some of the channels involved in canaliculi secretion.
MDR1-MDR3 cMOAT
describe the journey of bile salts.
produced in the liver, released in bile, reabsorbed by gut in jejunum but mainly terminal ileum and then conjugated in liver to amino acids.
what is bile made of?
water, bile salts, cholesterol + lecithin and bilirubin.
how are bile salts kept in the gallbladder?
arranged in micelles so that they don’t damage the gallbladder.
what increases bile viscosity?
mucin.
describe the metabolism of amino acids?
cannot be stored because ineffective energy source. they are deaminated to form a-keto acids. glutamate is deaminated for form a-ketoglutarate and fed into the krebs cycle. NH4+ gets excreted
how is a-ketoglutamate formed?
deamination of glutamate.
how is pyruvate formed?
deamination of alanine from muscle.
describe the glucose alanine cycle.
in muscle, glucose in converted to pyruvate via glycolysis. glycolysis is aminated to form alanine. in this process, glutamate is deaminated to a-ketoglutarate in the presence of the enzyme alanine aminotransferase, and the NH4+ is transferred to pyruvate to form alanine. alanine then travels in the blood to the liver where it is deaminated to form pyruvate again. during this process a-ketoglutarate is aminated to form glutamate, this process also uses alanine aminotransferase. the NH4+ is then put into the urea cycle. the pyruvate formed undergoes gluconeogenesis to form glucose again which gets transported to muscle.
how much albumin is produced per day? where does it go?
10g. it travels in the interstitium into lymph and into the thoracic duct to be empties into the left subclavian vein.
what is albumins half life? how many binding sites does it have?
16-18 hours. 4, all with difference specific binding sites.
which clotting factors are produced by the liver?
all but von willebrand.
what are microsomal enzymes? where are they found?
monooxydases. they can oxidise, reduce, or hydrolyse, and glucuronidation. CP450. smooth ER
what are nonmicrosomal enzymes? where are they found?
cytoplasm/mitochondria of hepatocytes. protein oxidases, esterases or conjugates.
what is phase 1 of detoxification?
phase 1 - cytochrome p450. xenobiotic is oxidised. results in some loss of function of the drug, can still be active. the reaction is non-synthetic. end result is a new/modified functional group.
what is phase 2 of detoxification?
conjugation. this reaction is synthetic. it is the attachment of an ionised group to completely inactivate the molecule e.g. methyl or acetyl group. makes it more soluble.
what does it mean to say that a reaction is synthetic?
produces a soluble compound that can be excreted in urine/faeces.
what is glucuronisation?
most common conjugation reaction in which glucuronic acid is added to the xenobiotic. BILIRUBIN!!!!!
what are vitamin A, C, B, D used for/deficiency?
A = retanoids, for seeing in dark. C = for synthesis of neurotransmitters. B = nucleic acid production. D = calcium metabolism.
what is BMR equivalent to? how is it measured?
ATP useage. O2 uptake
what do the brain, RBCs and liver use for energy?
brain = ketone bodies and glucose. RBCs use glucose. liver uses glucose, fatty acids, alcohol, AAs.
what is the total energy expenditure?
60% resting, 30% activity induced and 10% dietary. 70% is from fats and 30% is from carbs.
