L12- fats absorption Flashcards
why do we need to absorb fats
- 2x of energy can be stored as fat in the fasted state
where does the fat storage exist in what tissues
- most in subcutanoeus which is less metabolically active
- and rest in visceral which is more metabolically active
how is energy released from the fats
in beta-oxidation including Krebs cycle
steps in beta oxidation
- FA converted into fatty acetyl CoA
2. goes through a cycle where it’s oxidised, hydrated, oxidised then cleaved to release energy
what vitamins are fat soluble and can be absorbed
A,D,E and K
-absorbed as micelles for intestinal absorption
benefits of VIT A,D,E,K
A- strengthens vision and immunity
D- regulate the amount of calcium and phosphate in the body
E- protects against CVRS disease and Cancer
K- needs for blood clotting, helping wounds to heal.
what part of the fats that needs to be absorbed
FAs
-important in cellular processes, development of brain
disease due to FA deficiency
dry skin
weakness
low vision
edema
what types of fats can be consumed from diet
- trigylercides
- phospholipids
- cholestral
digestion of lipids
- chewed in the mouth by lingual lipase so the lipids particles can become emulision droplet
- digested further in the stomach by lipases
- releases FA go into duodenum and CCK released causing bile flow and secretion of pancreatic enzymes
what is the main lipolytic enzyme and what does it need
pancreatic lipase needs
- colipase
- bile salts
- alkaline pH
- FAs
function of colipase
- actd an an anchor for binding of lipase
what happens to the emulsion droplets so the FAs inside can be absorbed
- budding of the droplet occurs so it forms multimellar vesicles
- those vesicles interact with bile salts to form unilamellar vesicle
- then interacts with bile again to form mixed micelle containing FAs
what lipolytic products will be absorbed and how
- short/medium FA by diffusion
- FA in the micelle are protonated due to low pH due to Na-H exchange at the brush border. Then enters the enterocyte by non ionic diffusion
what happens once the lipids get into the enterocyte
- long chain FA becomes fat droplet and apoproteins join with them
- then joins with chylomicron which then fuses with the plasma membrane to release the droplet into the blood vessels
- smaller FA can diffuses out of the liver cells into the vessels
