wk 6 4 Biochem of liver Flashcards
where is the first destination of majority of nutrients and xenobiotics absorbed from GI tract
liver
before entering systemic circulation
4 other functions of liver
bile production
elimination of unwanted molecules (metabolism, excretion)
secretion of pproteins (albumin)
storage of important molecules
hepato insuffiency may be indicated in
stool colour change
-end stage liver disease= white poo
what aspect colours stool/urine
bilirubin
liver may also be considered a regulator of metabolism, how
carbo and lipid metabolism (stores fuels)
amino acid metabolism (urea cycle)
define electrophoressi
allows separation of proteins by size
blood plasma is composed of
albumin
globulins - alpha,beta, gamma
5 functions of plasma proteins
maintenance of oncotic/colloid osmotic pressure (dont exit via interstitial fluid, prevents loss of plasma)
transport of hydrophobic substances (steroids, fatty acids, bilirubin, cholesterol)
pH buffering
Enzymatic function (clotting)
Immunity
which globulin transports lipoproteins, lipid hormones and bilirubin
alpha globulin
transports vitA also
2 examples of beta globulins
transferrin (transfers Fe3+) (iron defiency)
fibrinogen (clots)
what hormone stimulates production of albumin
insulin
what decreases the level of albumin 3
starvation
low protein diet
liver disease
t/f albumin is negatively charged
true
if albumin has a low affinity for binding hydrophobic molecules, how is it able to transport them
high conc. of molecules
3 processes which iron is required
haemoglobin
myoglobin
cytochromes
what globulin transports copper
ceruloplasmin
what is copper requirred for? defiency indicated what disease
essential for regulation of redox reaction and use of iron
wilsons disease
what is steroid hormones derived from
cholesterol
t/f without transport proteins, hormones would be eliminated rapidly by liver/kidney
true
thyroxine bound to thyroid-binding globulin
cortisol bound to cortisol-binding globulin
t/f liver is only organ capable of metabolising and excreting cholesterol
true
when cholesterol is transported back to liver, what is it excreted by
bile salts via biliary system/faeces
3 vitamins stored in liver
vit A, D, and B12
what is iron stored as
ferritin
what is a major component of gall stones
cholesterol
t/f cholesterol is incorporated into lipoproteins and solubilised
true
located in core of molecule
cholesterol synthesis requires 3
acetyl-CoA (c atoms)
NADPH (reducing power))
ATP (energy)
what is the key rate limiting enzyme in cholesterol synthesis
HMG-CoA reductase
(target for controlling synthesis of cholesterol)`
mevalonic acid
rate limiting enzyme
unique to cholesterol synthesis
what is targeted in statins
HHMG-CoA reductase
products from cholesterol synthesis
Vit D (regulates calcium) Hormones - Corticosteroids Androgens Estrogens Bile salts (main)
cholestyramine is an anion exchange resin, what does it do
bind to bile salts
inhibits reabsorption in enterohepatic circulation
