Fat Metabolism Flashcards
What are the 3 main important fatty acids we absorb?
Palmitic (most abundant)
Stearic
Oleic acid
Where does triglyceride digestion occur?
Mouth and stomach (limited) Small intestine (predominantly)
What is the major fat digesting enzyme and where is it synthesized?
Lipase
Pancreas
What does lipase break triglycerides into?
Monoglyceride and 2 fatty acids
Where does lipid digestion start?
In the mouth
The lipids in ingested food are ….. in water so…..in the upper portion of the …..
Insoluble
Aggregate into large lipid droplets in the upper portion of the stomach
These aggregated lipids are converted into very small droplets by…
Emulsification
What are the 2 things required for emulsification?
Mechanical disruption - motility
Emulsifying agent - bile (or phospholipids in food)
What happens in emulsification?
Make fat droplets smaller, bile salts emulsify drop,ets further making them even smaller
BS coat the outside of the droplets to ensure they don’t reaggregate & form bigger droplets (join together)
What are bile salts formed from?
Cholesterol in the liver and are amphiphatic
What does amphiphatic mean?
Both hydrophilic and phobic
The coating of the lipid droplets with these emulsifying agents however, …..
Impairs the accessibility of the droplet for lipase
Lipase can’t bind
To overcome this issue, what is secreted and where is it secreted from and what does it do?
Colipase
Protein (coenzyme) from pancreas
Helps lipase bind, binds to droplet and lipase
These droplets are further converted into smaller droplets called……
These consist of…
micelles
Bile salts, fat soluble vitamins (ADEK) & cholesterol, FA, monoglycerides & phospholipids
Where are the contents of the micelles released at?
Contents released at intestinal brush border
(Low solubility in water so diffuse across lipid portion of luminal plasma membrane of epithelial cells of Small, intestine)
