Lipid Digestion Flashcards
(23 cards)
What percentage of energy requirement is provided by ingested lipids?
55%
What do ingested lipids comprise of?
Fats / Oil, phospholipids, cholesterol and cholesterol esters and fatty acids
Describe the solubility of ingested lipids
Insoluble or poorly soluble in water
What does gastric lipase do?
hydrolyses one of the 3 fatty acid tails
What is the significance of the double bonds and the length of the chains?
The length and strength of the molecule
What do fatty acids act as
Surfactant
What is CCK
A gut hormone
WHat is the role of bile salts
to confer polarity (polar charge) onto lipid molecules, act as detergents to emulsify large lipid drops to small droplets
Where are bile salts sectred from
Bile from the gall bladder
Bile salts are amphipathic. define this
hydrophilic group and hydrophilic group
What happens in failure to secrete bile salts
lipid malabsoption - steatorrhoea (fat in faeces) this can lead to secondary vitamin deficiency due to failure to absorb lipid soluble vitamins (ADEK)
What is the main purpose of the bile salts
To increase the surface area for action of lipase
What does the increased surface area allow for
Attack by pancreatic lipase
What does the increased surface area block?
access of the enzyme to the lipid with the hyrophobic core of the small droplets
Where are the final products of lipid digestion stored and released from?
Mixed Micelles
Where do short chain and medium chan fatty acids diffuse through>
Enterocyte
Where do short chains and medium chain fatty acids exit through?
The basolateral membraine and enter the villus capillaries
How long are long chain fatty acids ?
> 12 Carbons
Where are long chain fatty acids resynthesised?
In the Endoplasmic Reticulum
What does Apolipoprotein do
Apolipoprotein coats the lipid mecellls and forms a chylomicron
Where does chylomicron enter the systemic circulation and how
into the subclavian vein via through the thoacic duct
Where do chylomicron triglyceride metabolised in capillaries by lipoprotein lipase present?
Endothelial cells
What is the role of albumen?
To distribute fatty acids and glycerol to be carried away to tissues
