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Flashcards in Vitamins Deck (74)
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1

Fat soluble vitamins

Vitamins A, D, E, K

2

Water Soluble Vitamins

Vitamins C, B1, B2, B6, B12, folate, biotin, pantothenic acid
niacin

3

Vitamin A function

fat soluble vitamin
binds to cell nuclear receptors
provitamin A (carotene) - structure equivalent of 2 vitamin A molecules

4

processing of Vitamin A

Beta-carotene into retinal & then to retinol (active form) & retinoic acid

5

transport for Vitamin A

retinal binding protein

6

active form of vitamin A

retinol (OH group on the end)

7

toxic level of vitamin A

anything over 100 ug/dl

8

importance of vitamin A

growth, reproduction, immune system
cell differentiation - maintains epithelial integrity
vision- part of rhodopsin

9

Vitamin A role in vision

retinol is oxidized in rods of eye retina to retinal
the complexed w/ opsin to form Rhodopsin
sight in dim light

10

Vitamin A deficiency

lead to night-blindness- seen in malabsorption, liver impairment, premature infant
loss of hair
joint pain
headaches
drowsiness
vomiting

11

Hypervitaminosis A

vitamin A toxicity > 140 ug/dl in plasma
measured by HPLC

12

Vitamin E

(alpha-tocopherol); anti-oxidant - primary defense against oxidation of unsaturated lipids & cells

13

Vitamin E metabolism

40% absorbed from GI, attaches to chylomicrons for transport to liver
then transported via VLDL to cells
excreted through feces

14

deficiency of vitamin E

shows hemolytic anemia
can see in premature infants, fat malabsorption in adults
measured by HPLC

15

Vitamin K function

(napthoquinone); essential for coagulation factors

16

Vitamin K dependent coagulation factors

II, VII, IX, X also protein C & S

17

source of vitamin K

50% diet & 50% gut bacteria
absorbed into body via bile salts

18

lack of vitamin K

leads to hemorrhagic crisis
usually related to GI malabsorption & antibiotics

19

testing for vitamin K

use Prothrombin time (PT) -extended time
liver disease will also show low coag proteins but may not be vit K related

20

vitamin K toxicity

usually not seen in adults
children with vit K supplement at birth can see increase in bilirbuin
supplements rich in vit K : garlic, gingko, & ginseing

21

Vitamin D function

1,25 DHCC
facilitates calcium (& phosphorus) absorption

22

D2

ergocalciferol - not naturally occurring

23

D3

cholecalciferol
can make from sunshine on 7-dehydro-cholesterol

24

vitamin D absorption

absorb from gut; attaches to chylomicrons for transport to liver
stored in liver
excreted in bile

25

vitamin D stimulates

ca2+ absorption along w/ phosphorus from intestine
w/ PTH- increases mobilization of ca2+ from bone to circulation
has apoptotic effect - cancerous cells/ loses growth regulation

26

vitamin D deficiencies

children- ricketts
osteomalacia- softening of the bone
AED- hinder vit D absorption
any malabsorption condition or renal issue

27

vitamin D toxicity

children
hyperparathryoidism
hypophosphatemia
pregnancy
excess vitD leading to excess calcium deposits in heart & kidneys (damage can be irreversible)

28

laboratory testing for vitamin D

calcium testing - PTH, serum Ca2+, urine Ca2+
assay 25-OH-cholecalciferol or 25-OH vit D3 by immunassay or HPLC

29

vitamin B1 (thiamine)

used to make thiamine pyrophosphate TPP - important coenzyme
needed for decarboxylase subunits of dehydrogenase complexes

30

vitamin B1 metabolism

absorbed through GI
excreted through the kidney; out the urine