Biliary Secretion and EH secretion

Question 1

What are the 3 roles of Bile?

Answer 1

1) Lipid digestion/absorption
2) Cholesterol Homeostasis
3) Excretion of lipid soluble xenobiotics/drug metabolites/heavy metals

Question 2

Where are bile salts absorbed in the SI?

Answer 2

Jejunum

Question 3

What emulsifies lipids?

Answer 3

Bile Salts

Question 4

What do the end products of fat digestion along with bile salts and cholesterol form?

Answer 4

Mixed micelles

Question 5

What is the function of mixed micelles?

Answer 5

Lipid transport systems

Question 6

How much bile is produced by the liver daily?

Answer 6

500ml

Question 7

What does CCK induce?

Answer 7

Release of bile, as gallbladder contracts

Question 8

Were are bile salts reabsorbed?

Answer 8

Terminal Ileum

Question 9

What circulation returns bile salts to the liver?

Answer 9

Enterohepatic

Question 10

Where are gallstones found in obstructive jaundice?

Answer 10

CBD

Question 11

When does bile production start?

Answer 11

Week 12

Question 12

What is formation of bile dependent on?

Answer 12

Hepatic synthesis and canalicular secretion of bile acids

Question 13

Why do Bile Acids stay intraluminal?

Answer 13

So they are more likely to be reabsorbed

Question 14

What enzyme converts cholesterol into a primary bile acid?

Answer 14

Cholesterol 7 alpha hydroxylase

Question 15

What does emulsification do for lipolysis?

Answer 15

Increases the surface area

Question 16

Why are bile salts described as amphipathic?

Answer 16

(Both hydrophilic and hydrophobic parts)

Reduce surface tension and aid emulsification

Question 17

What are the functions of bile acids? (6)

Answer 17

1) Induce bile flow and secretion of biliary lipids
2) Digestion of dietary fats
3) Facilitate protein absorption
4) Cholesterol homeostasis
5) Antimicrobial
6) Prevent calcium gallstones, and oxalate renal stones

Question 18

Summarise bile formation and emulsification

Answer 18

1) Cholesterol bd by C8AH into Bile acids
2) Stored in Gallbladder and 10x conc
3) Makes fat into emulsion as micelles made and co-lipase work with lipase to break FA off TG into MG
4) Diffuse across enterocytes and reassembled as TG before excreted into lacteals as chylomicrons
5) Enter general circulation and BD by lipoprotein lipase on BV surface into FFA and MG