Phys Bile Secretion and Gall Bladder Function

Question 1

Describe resting condition of biliary system

Answer 1

sphincter of Oddi is closed. Bile flows from liver to gallbladder, which expands.

Question 2

contents of bile from liver

Answer 2

H2O
Ca++
K+
Cl-
Na+
Bile acids

Question 3

contents of bile modified by secretin

Answer 3

adds:
HCO3-
Na+
H2O

Question 4

What happens in gall bladder?

Answer 4

Removal of Na+, Cl-, HCO3-, H2O

Question 5

CCK function

Answer 5

opens sphincter of Odi, contraction of gallbladder

Question 6

How much of bile acid is lost in stool?

Answer 6

5%

Question 7

Where is cholesteral/bile salts reabsorbed

Answer 7

ileum

Question 8

How are bile salts reabsorbed?

Answer 8

K-dependent manner in ileum

Question 9

2 primary bile acids & why is primary a thing?

Answer 9

Cholic acid
Chenodexoxycholic acid

Primary bile acids are synthesized by the liver & nowhere else.

Question 10

2 secondary bile acids

Answer 10

deoxycholic acid (from cholic acid)
lithocholic acid (from chenodeoxycholic acid)

Question 11

2 amino acids with which to make bile salts

Answer 11

glycine, taurine

Question 12

why is it important to make a salt or an acid?

Answer 12

salt = hydrophilic/amphiphilic so stays in lumen
acid = more hydrophobic, so reabsorbed

Question 13

How is bile salt synthesis regulated and by what enzyme?

Answer 13

bile salts returning in enterohepatic circulation are rate-limiting and inhibited by 7alpha-hydroxylase

Question 14

choleretic effect

Answer 14

recirculation of bile salts to the liver stimulates biliary secretion

Question 15

how are bile acids excreted?

Answer 15

facilitated diffusion from hepatocytes

Question 16

how are bile salts absorbed from blood?

Answer 16

coupled to NaKATPase. BA/Na+ symporter.

Question 17

How & where is hemoglobin broken down?

Answer 17

reticuloendothelial system. Then bilirubin is transported by albumin to liver.

In liver: bilirubin glucaronide (conjugated bilirubin) secreted into bile (yellow). In intestine bilirubin is unconjugated, converted to urobilinogen (by intestinal bacteria), then oxidized to urobilin and stercobilin (dark stool’s color)

Question 18

what gives urine a yellow/brown color?

Answer 18

urobilin (from urobilinogen of gut)

Question 19

gallbladder removes what from bile?

Answer 19

NaCl & water

Question 20

Most common type of gallstones

Answer 20

cholesterol stones, forms around nidus

Question 21

10-20% of gall stones

Answer 21

pigment stones (unconjugated bilirubin)
gall bladder wall often damaged by bacteria & bile saturated by conjugated bilirubin

Question 22

removal of gallbladder does what to bile plot?

Answer 22

levels it out - no high peak of bile to digest upon feeding