bile and biliary Flashcards
what conditions are needed for max bile production?
low blood flow to liver for high pO2 conditions
what does raising ambient partial pressure of O2 in perfusate/blood from 700 to 3000 mmHg do to bile flow?
plateau
bile flow is independent of liver blood flow.
explain the relationship between bile pressure and blood pressure
bile and blood flow are linearly related
increase in BP causes incerase in liver sinusoid pressure
explain whether bile secretion is with or against a pressure gradient
Bile secretion can occur against a pressure gradient, so it is an active process and not due to hydrostatic forces from the blood
whats the significance of the location of the ampulla of vater
-halfway along 2nd part of duodenum
-marks the transition of foregut to midgut
(coeliac –> sup mesentetric)
what’s the composition of bile
Na, K, Ca, Cl, HCO3, P bile acids/salts fatty acids bilirubin phospholipids cholesterol proteins
how is bile made more concentrated
take out H2O of gall bladder
Na, Cl and H2O leave
H. and HCO3 enter the lumen of the gall bladder
what transporters/membrane proteins are in the gall bladder epithelium to make biles more concentrated
lumen surface: Na:H exchanger, HCO3:Cl exchanger, aquaporin
basolateral surface: K channel, 2K:3Na excnhger, Cl ion channel
what is bilirubin
breakdown of Hb, excreted in bile
- fat soluble and toxic
- travels in blood bound to albummin
normal and jaundice plasma bilirubin conc
3-10 mg/ml
> 18mg/ml
how is bilirubin formed
cholesterol (insoluble inwater) comes into solution by forming vesicles with phospholipids (lecithin)
or mixed micelles with bile salts and phospholipids
what does jaundince without abdominal pain suggest
obstruction of the bile duct
- jaundice associated with anorexia, soft stools
- non-biliary causes: inc bilirubin production, decreased clearance
what junctions are between gall bladder epithelial cells
tight junctions
what are mixed micelles made from
free fatty acids, monoglycerides, lysophospholipids, cholesterol
- made after fat is emulsified
what substances can diffuse passively through the intestinal cell
glycerol
short/medium chain FA