L12- fats absorption Flashcards

1
Q

why do we need to absorb fats

A
  • 2x of energy can be stored as fat in the fasted state
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2
Q

where does the fat storage exist in what tissues

A
  • most in subcutanoeus which is less metabolically active

- and rest in visceral which is more metabolically active

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3
Q

how is energy released from the fats

A

in beta-oxidation including Krebs cycle

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4
Q

steps in beta oxidation

A
  1. FA converted into fatty acetyl CoA

2. goes through a cycle where it’s oxidised, hydrated, oxidised then cleaved to release energy

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5
Q

what vitamins are fat soluble and can be absorbed

A

A,D,E and K

-absorbed as micelles for intestinal absorption

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6
Q

benefits of VIT A,D,E,K

A

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.

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7
Q

what part of the fats that needs to be absorbed

A

FAs

-important in cellular processes, development of brain

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8
Q

disease due to FA deficiency

A

dry skin
weakness
low vision
edema

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9
Q

what types of fats can be consumed from diet

A
  • trigylercides
  • phospholipids
  • cholestral
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10
Q

digestion of lipids

A
  1. chewed in the mouth by lingual lipase so the lipids particles can become emulision droplet
  2. digested further in the stomach by lipases
  3. releases FA go into duodenum and CCK released causing bile flow and secretion of pancreatic enzymes
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11
Q

what is the main lipolytic enzyme and what does it need

A

pancreatic lipase needs

  • colipase
  • bile salts
  • alkaline pH
  • FAs
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12
Q

function of colipase

A
  • actd an an anchor for binding of lipase
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13
Q

what happens to the emulsion droplets so the FAs inside can be absorbed

A
  • 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
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14
Q

what lipolytic products will be absorbed and how

A
  • 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
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15
Q

what happens once the lipids get into the enterocyte

A
  • 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
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16
Q

why do lipids need to binds with apoproteins

A
  • prevents leakage back into the lumen of SI
  • prevents lipid toxicity
  • makes sure FAs are transferred to the SER
17
Q

reasons for Fats malabsorption

A
  • impaired bile acis production
  • low lipase activity
  • impaired chylomicron formation