Lipid metabolism

Question 1

What process occurs in the stomach?

Answer 1

Emulsification

Question 2

Describe what happens during emulsification

Answer 2

1. Core body temp. helps to liquify lipid
2. This, and peristaltic movements aid in forming a lipid emulsion
3. Acid stable salivary and gastric lipases begin lipid hydrolysis
4. Water immiscible TAGs are degraded to FA which act as surfactants
5. Lipid droplets acquire a hydrophilic surface and break down into smaller particles

Question 3

Describe lipid digestion in the duodenum

Answer 3

1. Lipid emulsion ejected from stomach into duodenum which stimulates duodenum to secrete cholecystokinin
2. Cholecystokinin triggerws pancreas to secrete lipase, cholesteryl esterase and secretin
3. Secretin stimulates alkaline pancreatic fluid production and release of bile salts from gall bladder
4. Lipase digests TAG to monoglyverides and FA
5. Choelsteryl esterase yields free cholesterol and FA
6. Bile salts act as detergents and form lipid aggregates - micelles
7. Micells transported along SI to brush border where absorbed via diffusion by enterocytes
8. FA and MAG absorbed, water insoluble lipids poorly absorbed
9. Bile salts absorbed in ileum ad transported back to liver

Question 4

what metabolic process occurs in hepatocytes?

Answer 4

B-oxidation