Bile Production and Gallbladder Function

Question 1

What is bilirubin the product of?

Answer 1

vBilirubin is the breakdown product of haemoglobin

Question 2

What do sinusoidal spaces contain?

Answer 2

• 2% Kupffer cells (phagocytic)
• 1% Stellate cells or Ito cells
  
  • (fat or vitamin A storing)
• 2% Endothelial cells

Question 3

Describe sinusoids

Answer 3

• spaces between hepatocytes
• -filled with blood
• -wider than capillaries, fenestrated
• -lined with endothelial cells and
• -Kupffer cells (macrophages)
• -blood filtered by kupffer’s cells

Question 4

What is in/what goes on in the space of Disse?

Answer 4

• stella cells present,
• plasma solutes, not blood cells
• Kupffer cells cleanse blood of bacteria, toxins, parasites, aging RBCs as it passes
• cleansed blood passes through liver into systemic circulation

Question 5

What are the two stages of liver bile secretion?

Answer 5

1. Hepatocytes
2. Secretory epithelial cells (ductules and ducts)

Question 6

What are the three steps of bile secretion?

Answer 6

1. Hepatocytes actively secrete bile into the bile canaliculi
   
   2. Intrahepatic and extrahepatic bile ducts not only transport this bile but also secrete into it a watery, HCO3−-rich fluidThese first two steps may produce ∼1000 mL/day of so-called hepatic bile.
   3. Half the hepatic bile-(500 mL/day) is diverted to the gallbladder, which storesthe bile and iso-osomotically removes salts and water

Question 7

What does the liver convert cholesterol to?

Answer 7

Primary bile acids - cholic acid and chenodeoxycholic

Question 8

What are the four major components of bile?

Answer 8

1. Bile salts
2. Cholesterol/phospholipids
3. Bilirubin
4. Protein and components (Bicarb)

Question 9

What two functions does bile serve?

Answer 9

1. Fat digestion and absorption
2. waste product secretion

Question 10

What two important actions do bile salts have in the intestinal tract?

Answer 10

1. Emulsification of fat particles
2. absorption of… …. by micelles
   
   • Fatty acids
   • monoglycerides
   • cholesterol
   • other lipids

Question 11

Secretin is impostrant in stimulating bicarb from?

Answer 11

Cholangiocytes

Question 12

What does somatostatin do?

Answer 12

inhibits bile flow by lowering [cAMP]i, an effect opposite that of secretin.

This inhibition may be caused by enhancing fluid reabsorption by bile ducts.

Question 13

What does CCK do to the gall bladder?

Answer 13

• Relaxes sphincter of Oddi
• Increases bile flow into duodenum
• contracts gall bladder

Question 14

How are most bile salts reabsorbed?

Answer 14

reabsorbed by

 active transport in terminal Ileum and

 returned through the hepatic portal vein

 to the liver, which resecretes them in the

 bile

Question 15

Describe cholestasis

Answer 15

• suppression of bile secretion
• biliary constituents may be retained within the hepatocyte and regurgitated into the systemic circulation.

Question 16

What are the three major groups of negative effects of cholestasis?

Answer 16

1. regurgitation of bile components (bile acids, bilirubin) into the systemic

       circulation gives rise to the symptoms of jaundice and pruritus (itching).

   2. cholestasis damages hepatocytes, as evidenced by the release of liverenzymes (e.g. alkaline phosphatase) into the plasma.
   3. because the bile acids do not arrive in the duodenum, lipid digestion andabsorption may be impaired.

Question 17

How do many acute and chronic liver diseases cause cholestasis?

Answer 17

mechanical obstruction of the extrahepatic bile ducts or by impairing bile flow at the level of the hepatocytes or intrahepatic bile ducts.

Question 18

What is cholecystitis?

Answer 18

Inflammation of gall bladder

Question 19

What is cholangitis?

Answer 19

Inflammation of the biliary ducts

Question 20

What three things form gallstones?

Answer 20

1. Abnormal bile composition
2. Biliary stasis
3. Inflammation of gallbladder

Question 21

What are four contributing factors to gall stones?

Answer 21

• Supersaturation
• Gallbladder hypomotility
• Crystal nucleation
• Accretion within mucous layer