Lipid Digestion

Question 1

What percentage of energy requirement is provided by ingested lipids?

Answer 1

55%

Question 2

What do ingested lipids comprise of?

Answer 2

Fats / Oil, phospholipids, cholesterol and cholesterol esters and fatty acids

Question 3

Describe the solubility of ingested lipids

Answer 3

Insoluble or poorly soluble in water

Question 4

What does gastric lipase do?

Answer 4

hydrolyses one of the 3 fatty acid tails

Question 5

What is the significance of the double bonds and the length of the chains?

Answer 5

The length and strength of the molecule

Question 6

What do fatty acids act as

Answer 6

Surfactant

Question 7

What is CCK

Answer 7

A gut hormone

Question 8

WHat is the role of bile salts

Answer 8

to confer polarity (polar charge) onto lipid molecules, act as detergents to emulsify large lipid drops to small droplets

Question 9

Where are bile salts sectred from

Answer 9

Bile from the gall bladder

Question 10

Bile salts are amphipathic. define this

Answer 10

hydrophilic group and hydrophilic group

Question 11

What happens in failure to secrete bile salts

Answer 11

lipid malabsoption - steatorrhoea (fat in faeces) this can lead to secondary vitamin deficiency due to failure to absorb lipid soluble vitamins (ADEK)

Question 12

What is the main purpose of the bile salts

Answer 12

To increase the surface area for action of lipase

Question 13

What does the increased surface area allow for

Answer 13

Attack by pancreatic lipase

Question 14

What does the increased surface area block?

Answer 14

access of the enzyme to the lipid with the hyrophobic core of the small droplets

Question 15

Where are the final products of lipid digestion stored and released from?

Answer 15

Mixed Micelles

Question 16

Where do short chain and medium chan fatty acids diffuse through>

Answer 16

Enterocyte

Question 17

Where do short chains and medium chain fatty acids exit through?

Answer 17

The basolateral membraine and enter the villus capillaries

Question 18

How long are long chain fatty acids ?

Answer 18

> 12 Carbons

Question 19

Where are long chain fatty acids resynthesised?

Answer 19

In the Endoplasmic Reticulum

Question 20

What does Apolipoprotein do

Answer 20

Apolipoprotein coats the lipid mecellls and forms a chylomicron

Question 21

Where does chylomicron enter the systemic circulation and how

Answer 21

into the subclavian vein via through the thoacic duct

Question 22

Where do chylomicron triglyceride metabolised in capillaries by lipoprotein lipase present?

Answer 22

Endothelial cells

Question 23

What is the role of albumen?

Answer 23

To distribute fatty acids and glycerol to be carried away to tissues