Vitamin A Flashcards Preview

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Flashcards in Vitamin A Deck (51):
1

what are the three active forms (retinoids)? Vitamin A

retinol, retinal, retinoic acid

2

what are the four functions of the retinol form? Vitamin A

vision, sexual reproduction, bone health, immune function

3

what are the four functions of the retinal form? Vitamin A

vision, sexual reproduction, bone health, immune

4

what two forms can be converted back and forth to one another? Vitamin A

retinol and retinal

5

what are the three functions of the retinoic acid form? Vitamin A

cell differentiation, bone health, immune function

6

retinoic acid is formed from what? Vitamin A

retinal and its irreversible

7

which form is in foods? Vitamin A

retinol

8

which form is from plants (carotenoids)? Vitamin A

retinal

9

what are three other properties besides its function of retinoic acid? Vitamin A

 Excretion product
 Toxic
 Helps skin

10

which form is associated with carotenoids? Vitamin A

retinal

11

how many carotenoids are found in nature? Vitamin A

600

12

how many carotenoids have potential vitamin A activity? Vitamin A

50

13

the carotenoids without activity have what health benefits? Vitamin A

 i.e., Lycopene
 Antioxidant that protects against free radicals that initiate cancer

14

whats the efficiency of conversion of carotenoids? Vitamin A

40%

15

30% of carotenoids are what (what happens to them)? Vitamin A

absorbed intact as pigments and deposit in
fats

16

the excess amounts of carotenoids are what four things? Vitamin A

deep yellow color of palms, ear lobes & soles of feet: xanthosis cutis

17

what masks the carotenoids colors? Vitamin A

chlorophyll

18

what happens to green leaves that expose the carotenoids colors? Vitamin A

i.e., green leaves turn red, yellow in fall

19

what is its function in rats? Vitamin A

reproduction

20

vitamin A and vision deal with what? Vitamin A

Ability of eye to adapt to changes in light is dependent on Rhodopsin (visual purple)

21

what are the three details of Rhodopsin (visual purple)? Vitamin A

 Exposure to light bleaches it to form opsin + retinol
 Changes from cis (bent) to trans (linear) form  Stimulates electrical impulses to brain

22

there is constant need for replenishing for what function? Vitamin A

vision

23

what is Nyctalopia? Vitamin A

Night blindness: lack of vitamin A (retinol); Eye cannot readapt easily to darkness

24

how much is in the eye? Vitamin A

1%

25

what two parts of the skin does it deal with in skin integrity via cell differentiation? Vitamin A

 Mucous membranes of epithelial cells
 Epithelial tissues (eye, mouth, skin, GI, respiratory tract, genitourinary tract) have goblet cells that secrete mucus

26

what do the Epithelial tissues that have goblet cells that secrete mucus do during a cold? Vitamin A

flow increases to wash away virus

27

what is the enzyme used in the Epithelial tissues that have goblet cells that secrete mucus during a cold and what does that enzyme do? Vitamin A

lysozymes: degrades foreign
bacteria

28

what happens to the function of skin integrity via cell differentiation in the cells when there is a deficiency? Vitamin A

cells keratinize  Harden, dry, flake off

29

what happens to the function of skin integrity via cell differentiation in the eyes when there is a deficiency? Vitamin A

cornea dries & hardens Xeropthalmia

30

what happens to the function of skin integrity via cell differentiation in the salivary glands when there is a deficiency? Vitamin A

dry, mouth cracks

31

what happens to the function of skin integrity via cell differentiation in the respiratory tract when there is a deficiency? Vitamin A

cilia dries & lost
 Open to invading organisms

32

what happens to the function of skin integrity via cell differentiation in the skin when there is a deficiency? Vitamin A

hardened eruption around hair follicles
(toad skin)

33

what happens in the functions of growth (& Reproduction in Rats)? Vitamin A

Attaches to binding proteins in cell nucleus to stimulate
differentiation of cells

34

what happens with its function of growth (& Reproduction in Rats) when there is a deficiency in the skeletal bone? Vitamin A

destroys old bone for remodeling
 Bone overgrowth

35

what happens with its function of growth (& Reproduction in Rats) when there is a deficiency in the teeth? Vitamin A

Malformation

36

what happens with its function of growth (& Reproduction in Rats) when there is a deficiency in the reproduction (rats)? Vitamin A

 Male:No spermatogenesis  Female: Fetal resorption

37

what happens with its function in immunity? Vitamin A

Helps fight infection by maintaining healthy epithelial cells & mucous
proteins in intestines & lungs

38

what are the three things that happen to the immunity function with a deficiency? Vitamin A

 Decreased activity of white blood cells (T-
lymphoctyes)
 Increased risk of dying from measles in children  Increased cancers of epithelial cells

39

what does lycopene reduce the risk of? Vitamin A

Reduced risk prostrate cancer

40

who got toxicity by eating what type of liver? Vitamin A

Explorers ate polar bear liver

41

what are the five toxicity symptoms? Vitamin A

 Drying, desquamation of skin
 Bone abnormalities
 Hemorrhage
 Liver Failure
 Death

42

what happens with the toxicity symptom of Drying, desquamation of skin? Vitamin A

Hair loss / skin rash

43

what happens with the toxicity symptom of Bone abnormalities? Vitamin A

Headaches, bone & joint pain

44

what are the two things that happen with toxicity in pregnancy? Vitamin A

Accutane --> Dries skin; Birth Defects

45

when are the effects of toxicity in pregnancy seen? Vitamin A

3 X RDA

46

whats the RDA? Vitamin A

 Men: 900 μg RAE  Women: 700 μg RAE

47

whats the Retinol activity equivalents (RAE)? Vitamin A

1 μg of retinol =1 μg RAE

48

1 μg RAE equals how much beta carotene? Vitamin A

12 μg

49

1 μg RAE equals how much alpha carotene and beta cryptoxanthin? Vitamin A

24 μg

50

what are the scientific names of the food sources? Vitamin A

Preformed Retinol; Proform: Carotenoids

51

what are the four main foods sources? Vitamin A

beef liver, sweet potatoes, carrots, fortified cornflakes