bile and biliary

Question 1

what conditions are needed for max bile production?

Answer 1

low blood flow to liver for high pO2 conditions

Question 2

what does raising ambient partial pressure of O2 in perfusate/blood from 700 to 3000 mmHg do to bile flow?

Answer 2

plateau

bile flow is independent of liver blood flow.

Question 3

explain the relationship between bile pressure and blood pressure

Answer 3

bile and blood flow are linearly related

increase in BP causes incerase in liver sinusoid pressure

Question 4

explain whether bile secretion is with or against a pressure gradient

Answer 4

Bile secretion can occur against a pressure gradient, so it is an active process and not due to hydrostatic forces from the blood

Question 5

whats the significance of the location of the ampulla of vater

Answer 5

-halfway along 2nd part of duodenum
-marks the transition of foregut to midgut
(coeliac –> sup mesentetric)

Question 6

what’s the composition of bile

Answer 6

Na, K, Ca, Cl, HCO3, P
bile acids/salts
fatty acids
bilirubin
phospholipids
cholesterol 
proteins

Question 7

how is bile made more concentrated

Answer 7

take out H2O of gall bladder
Na, Cl and H2O leave
H. and HCO3 enter the lumen of the gall bladder

Question 8

what transporters/membrane proteins are in the gall bladder epithelium to make biles more concentrated

Answer 8

lumen surface: Na:H exchanger, HCO3:Cl exchanger, aquaporin

basolateral surface: K channel, 2K:3Na excnhger, Cl ion channel

Question 9

what is bilirubin

Answer 9

breakdown of Hb, excreted in bile

• fat soluble and toxic
• travels in blood bound to albummin

Question 10

normal and jaundice plasma bilirubin conc

Answer 10

3-10 mg/ml

> 18mg/ml

Question 11

how is bilirubin formed

Answer 11

cholesterol (insoluble inwater) comes into solution by forming vesicles with phospholipids (lecithin)
or mixed micelles with bile salts and phospholipids

Question 12

what does jaundince without abdominal pain suggest

Answer 12

obstruction of the bile duct

• jaundice associated with anorexia, soft stools
• non-biliary causes: inc bilirubin production, decreased clearance

Question 13

what junctions are between gall bladder epithelial cells

Answer 13

tight junctions

Question 14

what are mixed micelles made from

Answer 14

free fatty acids, monoglycerides, lysophospholipids, cholesterol
- made after fat is emulsified

Question 15

what substances can diffuse passively through the intestinal cell

Answer 15

glycerol

short/medium chain FA

Question 16

what is an entrocyte

Answer 16

intestinal lining cell

Question 17

what are long-chain FAs, and everything in the micelle re-esterified to after absorption into the enterocyte

Answer 17

re-esterified and reassembled n the SER and Golgi with apoproteins to chylomicrons

Question 18

what happens to chylomicrons after they’ve been produced

Answer 18

exocytosed (fuse w basolateral surface) and exported to the lymph (lacteals) which take it to the thoracic duct via left subclavian

Question 19

what do canaliculi drain into

Answer 19

peritubular bile duct–> interlobular bile duct