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):
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)

31

Ca++ channel on brush border:

TRPV6

32

Vit D deficiency characterized by seizures, growth retardation, failure of bone mineralization (osteomalacia):

rickets

33

Most toxic vitamin?

D

34

Vit associated with reduced colorectal carcinoma:

vit D

35

Most abundant metal ion in the body:

Calcium

36

HOw does Ca++ get across basolateral membrane?

Ca++ ATPase

37

Transcellular movement of Ca is regulated by?

calcitrol

38

Pericellular transport of Ca is regulated by?

Claudin

39

Inhibits PTH?

calcitonin

40

Intracellular signalling by calcium is mediated by?

calmodulin

41

How does Ca decrease cholesterol?

traps bile salts and fatty acids in undigestable soaps --> diverts cholesterol to bile salt synthesis

42

Saturable transport of Mg+ across brush border?

TRPM6

43

Basolateral transport of Mg+?

1. 2Na+ / Mg2+ antiporter

2. 2K+ / 3Na+ ATPase (creates favorable Na conc for #1 above)

44

Functions of Mg++?

bone

ATP

kinases

polymerases

45

Best measurement of Mg++?

renal excretion

46

SLC12A3 mutation

Gitelman Syndrome

47

Intracellular processes dependent on Mg++:

ATP associated processes