Wk1 Fat soluble vit/minerals/elect pt 1 Flashcards Preview

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Flashcards in Wk1 Fat soluble vit/minerals/elect pt 1 Deck (47)
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1

Define EAR (Estimated Average Requirement)

Average daily nutrient intake level estimated to meet the requirements of of half of the healthy members of a particular life stage and gender group

2

Define RDA (Recommended Daily Allowance)

Average daily dietary nutrient intake level sufficient to meet the nutritional requirements of nearly all (97-98%) healthy persons in a particular life stage and gender group

3

Define Tolerable Upper Limit:

Risk of "overdose" is approx. 0.1%

4

Biologically active form of vit A:

all-trans-retinol

-B-ionone ring
-branched polyunsaturated acyle chain
-alcohol

5

Three things all-trans-retinol can be converted to:

1. aldehyde

2. carboxylic acid

3. ester w/ fatty acid (eg. palmitate)

6

Three dietary forms of vit A:

1. retinyl palmitate

2. B-carotene

3. a-carotene

7

Vit A metabolite that can be transported in blood with albumin:

Retinoic acid

8

Vit A metabolites that are transported in chylomicrons:

Retinyl-fatty acid esters

9

Reservoir for vit A storage in liver:

Stellate cells

10

retinal cycle in photoreceptors?

cis-retinal + opsin = rhodopsin

rhodopsin + UV light = opsin + tras-retinal

trans-retinal --> G-protein rec. --> closes Na+ channels --> hyperpolarization of rod cell --> signals neuron

trans-retinal recycled back to cis-retinal

11

4 roles of retinoic acid ligand based transcription factors (RAR, RXR, PPAR):

1. differentiation of goblet cells (inhibits keratinization)

2. apoptosis of cancer cells

3. maturation of dendritic cells

4. recruitment of antibody secreting cells to small intestine

12

Vit A metabolites that act as antioxidants:

carotenes (double bonds bind free radicals)

13

Bitot's spots in the eye?

Vit A deficiency

14

Dry eye due to keratinization?

xeropthalmia

due to vit A deficiency

15

Vit E form with SATURATED 16-C acyl chains:

tocopherols

16

Vit E form with polyUNsaturated 16-C acyl chains:

tocotrienols

17

Vit E absorption and distribution parallels _____?

fat digestion and absorption

18

Vit E functions?

1. lipid bilayers

2. intracellular plasma membranes

3. cellular oxidative stress defense

19

Vit that can inhibit Vit K absorption and metabolism:

Vit E

20

Vit E deficiency: Causes? Symptoms?

Causes:
-premature infants
-Crohns
-short bowel syndrome

Sx:
-myopathy
-hemolytic anemia
-peripheral neuropathy
-ataxia, loss of vibratory sense

21

Main form of dietary vit K:

Phylloquinone

green leafy vegetables

22

Vit K produced by fermentation:

Menaquinones

23

Vit K absorption paralells _____.

fat

24

Vit K stored in _______.

cell membranes of lung, kidney, bone marrow, adrenal glands

25

Coumadin blocks what enzyme?

vit k epoxide reductase

**increases PTT

26

Clotting factors reliant on vit K dependent carboxylation:

VIIa

IX

X

27

Main circulating form of vit D:

25-hydroxycholecalciferol

28

Biologically active form of vit D:

1,25-dihydrocholecalciferol

29

Where does vit D get activated:

kidney

**in response to PTH

30

Enzyme in kidney responsible for activating vit D:

1-a-hydroxylase (+ PTH)