18: Hepatobiliary Function

Question 1

Two main components f bile

Answer 1

Bile salts and phospholipids

Question 2

NTCP and OATP1B1 function

Answer 2

Transport bile salts from blood -> hepatocyte

Question 3

Na dependent and independent transporters for bile from blood into hepatocyte

Answer 3

NTCP: Na-dependent
OATP: Na-independent

Question 4

Two mechanisms that cause bile secretion

Answer 4

1. Most bile: driven by bile acids, as bile as secreted into canaliculi, cations passively follow
2. Small portion due to secretin -> stimulates bicarb and water into bile

Question 5

What inhibits cholesterol 7a hydroxylase in negative feedback

Answer 5

Bile salts

Question 6

Five treatments for Crigler-Najjar syndrome

Answer 6

1. Phototherapy
2. Blood transfusions
3. Oral Ca PO3 and carbonate
4. Liver transplant
5. Phenobarbital

Question 7

How excess alcohol leads to sirrhosis

Answer 7

Alcohol -> fatty liver -> steatohepatitis -> scarring of liver / cirrhosis

Question 8

What causes portal hypertension

Answer 8

Cirrhosis

Question 9

Two things that occur with portal hyptertension

Answer 9

1. Esophageal varices

2. Caput medusae

Question 10

Hepatic encephalopathy

Answer 10

Decreased urea cycle in liver -> accumulation of ammonia in circulation -> ammonia readily crosses BBB to alter brain function

Question 11

What is jaundice a sign of?

Answer 11

Hyperbilirubinemia

Question 12

Physiological neonatal jaundice

Answer 12

Increased unconjugated bilirubin in blood first week post-natal

Question 13

Two main causes of physiological neonatal jaundice

Answer 13

1. Bilirubin production elevated from increased breakdown of fetal RBCs
2. Low ADP glucuronyl transferase activity

Question 14

How does phototherapy work for jaundice?

Answer 14

Isomerizes trans-bilirubin to water-soluble cis-bilirubin

Question 15

Two types of liver function tests

Answer 15

Biochemical and function tests

Question 16

Biochemical tests

Answer 16

Liver enzyme counts - ALT and AST, alkaline phosphatase

Question 17

What does elevated aminotransferases mean? (ALT and AST)

Answer 17

Hepatocyte injury

Question 18

What does elevated alkaline phosphatase mean?

Answer 18

Bile duct injury

Question 19

Three main function tests for the liver

Answer 19

Bilirubin, albumin, PT (prothrombin time)

Question 20

Bilirubin test

Answer 20

Measures livers ability to detox metabolites and transport organic anions into bile

Question 21

Albumin test

Answer 21

If hepatocytes are severely impaired, albumin in plasma will be low (albumin synthesized exclusively in liver)

Question 22

Hypoalbuminemia can also be seen in what?

Answer 22

Kidney disease?

Question 23

PT test

Answer 23

Reflects hepatic synthetic function

Question 24

When is PT high?

Answer 24

When cirrhotic liver loses ability to synthesize clotting factors?