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GI > VITAMINS > Flashcards

VITAMINS Flashcards

1
Q

Vitamin A fat soluble ?

A

yes

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2
Q

where is Vitamin A stored

A

Store in ito cells in the space of Disse of the liver

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3
Q

function of vitamin A

A
  • Cellular growth & differentiation
  • Process of vision (retinal pigments)•Healthy skin
  • Reproduction
  • Embryonic development
  • Maintenance of bodies mucus membranes
  • Used in lymphocyte production - immune system
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4
Q

Sources of Vitamin A

A
  • Liver
  • Dairy products
  • Oily fish
  • Margarine
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5
Q

what happens with Vitamin A deficiency

A
  • Night blindness
  • Xerophthalmia (eye fails to produce tears)
  • Growth retardation
  • Keratinisation of epithelia
  • Impaired hearing, taste & smell
  • Increased susceptibility to infection
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6
Q

What is Vitamin C soluble in

A

water

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7
Q

Functions of Vitamin C

A
  • Synthesis of; collagen, neurotransmitters & carnitine (used in beta-oxidation)
  • Antioxidant ability - can donate electrons to radical O2 compounds
  • Absorption of non-haem (plant based) iron
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8
Q

Sources of Vitamin C

A
  • Citrus fruits
  • Green leafy vegetables
  • Potatoes
  • Kidney
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9
Q

What happens with Vitamin C deficiency

A
  • Initial signs are non-specific
  • Weakness
  • Bleeding gums
  • Hyperkeratosis (thickening of outer layer of skin)
  • 50 - 100 days without Vitamin C = signs of scurvy
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10
Q

What is vitamin B soluble in

A

Water

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11
Q

Function of Vitamin B

A

•Important in cell metabolism & energy production

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12
Q

What is main vitamin B

A

B12

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13
Q

Where is Vitamin B12 found

A

found in fish, poultry, meat & eggs

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14
Q

what happens with vitamin B12 deficiency

A

Deficiency results in less erythrocyte formation - pernicious anaemia

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15
Q

Where is Vitamin B12 absorbed

A

terminal ileum

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16
Q

What is required for the absorption of Vitamin B12

A

For absorption, intrinsic factor is required which is produced by the parietal cells of the stomach

17
Q

What is vitamin D absorbed in

A

fat

18
Q

How long can the liver prevent defence of Vitamin D for

A

Liver storage prevent deficiency for 3-4 months

19
Q

Types of Vitamin D

A

D2

D3

20
Q

how is D3 formed

A

Vitamin D3 (cholecalciferol) is formed by the action of ultra-violet (UV) radiation from sunlight on a cholesterol derivative in the skin

21
Q

what is cholecalciferol

A

Vitamin D3

22
Q

How is Vitamin D2 derived

A

is derived from plants

23
Q

How is vitamin D metabolised

A

Its metabolised by the addition of hydroxyl groups, first in the liver and then in certain kidney cells,
the end result of these changes is 1,25-dihydroxyvitamin D (1,25-(OH)2D) - the active hormonal form of vitamin D

24
Q

Functions of 1,25-(OH)2D

A

Its major action is to stimulateintestinal absorptionof Ca 2+ and phosphate

25
Q

(1) Vitamin D deficiency

What first happens if there is a Vitamin D deficiency

A
  • Major consequence is decreased intestinal Ca2+ absorption resulting in a decreased plasma Ca2+
  • This decrease in detected via a plasma membrane Ca2+ receptor in the parathyroid glands (embedded in the posterior surface of the thyroid gland)
26
Q

(2) Vitamin D deficiency

what happens when the plasma membrane Ca2+ receptor in the parathyroid glands detects decreased plasma Ca2+

A

Resulting in the parathyroid glands releasing PARATHYROID HORMONE (PTH)which exerts multiple actions that increase extracellular Ca2+ concentration:

27
Q

(3) Vitamin D deficiency

what multiple actions are exerted to increase extracellular Ca2+ conc by parathyroid hormone (4)

A
  1. It directly increases the resorption of BONE by osteoclasts, which causes Ca2+ & phosphate ions to move from bone into the extracellular fluid - this can lead to a decrease in bone mass - osteoporosis (higher incidence of bone fractures etc.)
  2. It directly stimulates the formation of 1,25-dihydroxyvitamin D which then increases intestinal absorption of Ca2+ & phosphate ions, thus the effect of PTH on the intestines is indirect
  3. It directly increases Ca2+ reabsorption in the kidneys, thereby decreasing urinary Ca2+ excretion
  4. It directly decreases the reabsorption of phosphate ions in the kidneys thereby increasing its excretion in the urine - this keeps plasma phosphate ions from increasing when PTH causes an increased release of both Ca2+ & phosphate ions from the bone and an increased production of 1,25-dihydroxyvitamin D leading to calcium & phosphate ion absorption in the intestine
28
Q

What is Vitamin E soluble in

A

Fat

29
Q

Main function of Vitamin E

A

antioxidant

30
Q

What is Vitamin K soluble in

A

Fat

31
Q

Main function of vitamin K

A

Main function is that is is essential for the production of clotting factors (10,9,7 & 2) in the liver

GI (7 decks)

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