Liver physiology

Question 1

Where does arterial and venous blood mix in the liver?

Answer 1

Sinusoids

Question 2

In which direction does bile secreted by the hepatocytes flow and in which structure?

Answer 2

Canaliculi - flows outwards to bile ducts at corners of hepatocyte

Question 3

Which membrane are the canaliculi formed from?

Answer 3

Apical membrane

Question 4

Which space does the basolateral membrane of the liver lobule face?

Answer 4

The space of disse

Question 5

How many cells thick are the plates between the sinusoids?

Answer 5

Two

Question 6

What is the space of Disse?

Answer 6

The extracellular space between the hepatocytes of the basolateral membrane and the sinusoid

Question 7

What are Kuppfer cells?

Answer 7

Macrophages which are resident in the sinusoids - remove bacteria and old erythrocytes

Question 8

What are stellate (Ito) cells?

Answer 8

Cells resident within the space of Disse which are important in vitamin A storage

Question 9

Starting with the canuliculi, what does the intrahepatic bile system consist of?

Answer 9

Canaliculi  
Terminal bile ductules  
Perilobular ducts  
Interlobular ducts  
Septal ducts  
Lobar ducts  
Two hepatic ducts  
The common hepatic duct

Question 10

What does cholecystokinin stimulate?

Answer 10

Contraction of gall bladder smooth muscle

Opening of sphincter of Oddi

Question 11

Where is bile secreted from?

Answer 11

Hepatocytes

Bile duct cells/cholangiocytes

Question 12

What does hepatocyte bile consist of?

Answer 12

Primary bile acids mainly cholic and chenodeoxycholic acids (form bile salts with Na+ and K+)
Water and electrolytes including Na+, K+, Ca2+, Cl- and HCO3-
Lipids and phospholipids (e.g. lecithin)
Cholesterol
IgA
Bilirubin

Question 13

Which substance may be used to dissolve non-calcified gallstones?

Answer 13

Ursodeoxycholic acid

Question 14

How are bile salts synthesised?

Answer 14

From cholesterol in a series of 14 reactions, first mediated by cholesterol 7alpha-hydroxylase (CYP7alpha1) to form the primary bile salts

Question 15

What is the rate of bile salt synthesis dependant on?

Answer 15

Hepatic portal blood concentration of the salts
Low concentrate stimulates synthesis
High concentration inhibits synthesis

Question 16

What action does secretin have on the liver/bile ducts?

Answer 16

Causes aqueous alkaline bile secretion

Question 17

What action do opiates have on the sphincter of Oddi?

Answer 17

Constriction

Question 18

What is the aim of drug metabolism by the liver?

Answer 18

Convert parent drugs to more polar metabolites that are not readily reabsorbed in the renal tubules, facilitating excretion
Convert drugs to metabolites that are usually pharmacological less active than the parent compound

Question 19

What does phase 1 of drug metabolism by the liver involve?

Answer 19

Adds a reactive group to a drug e.g. by reduction, oxidation or hydrolysis to allow conjugation in phase 2

Question 20

What does phase 2 of drug metabolism by the liver involve?

Answer 20

Conjugation - adds an endogenous compound increasing polarity