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GI > Wk1 Fat soluble vit/minerals/elect pt 1 > Flashcards

Wk1 Fat soluble vit/minerals/elect pt 1 Flashcards

1
Q

Define EAR (Estimated Average Requirement)

A

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

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2
Q

Define RDA (Recommended Daily Allowance)

A

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

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3
Q

Define Tolerable Upper Limit:

A

Risk of “overdose” is approx. 0.1%

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4
Q

Biologically active form of vit A:

A

all-trans-retinol

  • B-ionone ring
  • branched polyunsaturated acyle chain
  • alcohol
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5
Q

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

A
  1. aldehyde
  2. carboxylic acid
  3. ester w/ fatty acid (eg. palmitate)
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6
Q

Three dietary forms of vit A:

A
  1. retinyl palmitate
  2. B-carotene
  3. a-carotene
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7
Q

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

A

Retinoic acid

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8
Q

Vit A metabolites that are transported in chylomicrons:

A

Retinyl-fatty acid esters

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9
Q

Reservoir for vit A storage in liver:

A

Stellate cells

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10
Q

retinal cycle in photoreceptors?

A

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

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11
Q

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

A
  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
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12
Q

Vit A metabolites that act as antioxidants:

A

carotenes (double bonds bind free radicals)

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13
Q

Bitot’s spots in the eye?

A

Vit A deficiency

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14
Q

Dry eye due to keratinization?

A

xeropthalmia

due to vit A deficiency

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15
Q

Vit E form with SATURATED 16-C acyl chains:

A

tocopherols

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16
Q

Vit E form with polyUNsaturated 16-C acyl chains:

A

tocotrienols

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17
Q

Vit E absorption and distribution parallels _____?

A

fat digestion and absorption

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18
Q

Vit E functions?

A
  1. lipid bilayers
  2. intracellular plasma membranes
  3. cellular oxidative stress defense
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19
Q

Vit that can inhibit Vit K absorption and metabolism:

A

Vit E

20
Q

Vit E deficiency: Causes? Symptoms?

A

Causes:

  • premature infants
  • Crohns
  • short bowel syndrome

Sx:

  • myopathy
  • hemolytic anemia
  • peripheral neuropathy
  • ataxia, loss of vibratory sense
21
Q

Main form of dietary vit K:

A

Phylloquinone

green leafy vegetables

22
Q

Vit K produced by fermentation:

A

Menaquinones

23
Q

Vit K absorption paralells _____.

A

fat

24
Q

Vit K stored in _______.

A

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

25
Q

Coumadin blocks what enzyme?

A

vit k epoxide reductase

**increases PTT

26
Q

Clotting factors reliant on vit K dependent carboxylation:

A

VIIa

IX

X

27
Q

Main circulating form of vit D:

A

25-hydroxycholecalciferol

28
Q

Biologically active form of vit D:

A

1,25-dihydrocholecalciferol

29
Q

Where does vit D get activated:

A

kidney

**in response to PTH

30
Q

Enzyme in kidney responsible for activating vit D:

A

1-a-hydroxylase (+ PTH)

31
Q

Ca++ channel on brush border:

A

TRPV6

32
Q

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

A

rickets

33
Q

Most toxic vitamin?

A

D

34
Q

Vit associated with reduced colorectal carcinoma:

A

vit D

35
Q

Most abundant metal ion in the body:

A

Calcium

36
Q

HOw does Ca++ get across basolateral membrane?

A

Ca++ ATPase

37
Q

Transcellular movement of Ca is regulated by?

A

calcitrol

38
Q

Pericellular transport of Ca is regulated by?

A

Claudin

39
Q

Inhibits PTH?

A

calcitonin

40
Q

Intracellular signalling by calcium is mediated by?

A

calmodulin

41
Q

How does Ca decrease cholesterol?

A

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

42
Q

Saturable transport of Mg+ across brush border?

A

TRPM6

43
Q

Basolateral transport of Mg+?

A
  1. 2Na+ / Mg2+ antiporter

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

44
Q

Functions of Mg++?

A

bone

ATP

kinases

polymerases

45
Q

Best measurement of Mg++?

A

renal excretion

46
Q

SLC12A3 mutation

A

Gitelman Syndrome

47
Q

Intracellular processes dependent on Mg++:

A

ATP associated processes

GI (46 decks)

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