Fat Digestion Flashcards
How is fat ingested
Triglycerol - Glycerol + 3FA
Insoluble
Where does fat digestion take place
Small intestine
Lipase pancreatic enzyme
What is lipase pancreatic enzyme
Water soluble
Only takes place on hydrophilic head so slow
What is emulsification
Dividing large lipids into smaller droplets to increase SA for lipase action
What does an emulsifying agent do
Prevents small droplets reforming as coats them so they repel
What are the emulsifying agents in GI tract and how do they work
Bile salts and phospholipids
Ampiphatic
Non-polar association with non-polar of lipid leaving polar exposed at water which repel other polar
What are micelles
Similar to emulsion droplets bur smaller
Enhance absorption
Bile salt + monoglyceride + FA + phospholipid + cholesterol
How do micelles work
Release small amounts of free Fa and monoglycerides which can diffuse across plasma membrane of absorbing cells
What happens when FA inside enterocyte
Move to SER Recombine into triglyceride Join cholesterol to form chylomicrons Packaged into vesciles Exocytosed Absorbed into lacteals Pass through lymph system into IVC
How are fat soluble vitamins A,D,E,K absorbed
Same as fat
How are water soluble vitamins absorbed - B,C,folic acid
Passive diffusion
Carrier mediated
How is B12 absorbed
Binds to intrinsic factor in stomach
Absorbed in distal ileum
Most other substances absorbed in jejunum
How are dietary minerals absorbed
Iron transported via DMTI into duodenal enterocytes
Needs to be Fe2+
Stored as ferritin
Transported as transferrin to liver
