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45 Cards in this Set
- Front
- Back
name the lipid soluble vitamins
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A,D,E and K
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are lipid soluble vitamins regularly excreted in the urine?
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no
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what foods have vitamin A?
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liver, egg yolk, butter and whole milk- green and yellow vegetables provide carotenes which is a precursor of vitamin A
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where is vitamin A stored?
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liver
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forms of vitamin A
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retinol, retinal, retinoic acid, B-carotene
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where does retinal come from?
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oxidation of retinol
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where does retinoic acid come from?
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oxidation of retinal
cannot be reduced in the body irreversible |
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what does B-carotene produce?
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cleaved in the intestine to give two molecules of retinal-antioxidant
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functions of vitamin A using every form but retinoic acid?
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growth of bone, vision and reproduction
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main function of retinoic acid?
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promotes growth and differentiation of epithelial cells
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function of Vitamin A using all forms
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keratinization of taste buds
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earliest sign of vitamin A deficiency?
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night blindness
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xerophthalmia
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pathologic dryness of the conjunctiva and cornea-can lead to blindness
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results of vitamin A deficiency
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anemia-transferrin synthesis
follicular hyperkeratosis |
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clinical uses of vitamin A
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acne and psoriasis- retinoic acid
prevention of chronic disease-reduced risk of heart disease, lung and skin cancer, cataracts and macular degeneration |
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main action of vitamin D
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regulate plasma levels of Ca and phosphorus along with immunity, insulin secretion and cell proliferation
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preforms of active vitamin D
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D2(ergocalciferol)-in plants
D3(cholecalciferol)- in animals |
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vitamin D2
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ergocalciferol-found in plants, produced by irradiating ergosterol from yeast, used to fortify milk, butter etc.
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vitamin D3
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cholecalciferol-found in animals, produced in skin by UV irradiation of dehydrocholesterol
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the primary storage form of vitamin D
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25-hydroxyvitamin D3
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sequence of vitamin D activation?
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7-dehydrocholesterol(irradiation), cholecalciferol(hydroxylation), calcidiol-if needed then hydroxylated to calcitriol, if not the hydroxylated to 24,25-dihydroxyvitamin D3 which is inactive
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sources of vitamin D
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salt water fish, liver, egg yolk, fortified milk and butter
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effect of PTH on vitamin D synthesis?
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high PTH stim. active vitamin D synthesis
low PTH stim. inactive vitamin D synthesis |
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vitamin D deficiencies
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nutritional rickets
renal rickets-no active form hypoparathyroidism-hypocalcemia because of no PTH osteoporosis-no Ca absorption in the gut muscle weakness |
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functions of vitamin D
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uptake of Ca and phosphorus by intestine
inhib. excretion of Ca in kidney stim. resorption of bone |
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PTH's effect on the kidney
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incr. Ca reabsorption but incr. phosphorus excretion
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most toxic vitamin
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D-stored in fat can cause loss of appetite, nausea, thirst and stupor
excess bone resorption-deposition in organs |
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non-calcium related functions of vitamin D3
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differentiation of T cells,immunosuppressive effect on dendritic cells, antimicrobial activity in human monocytes and neutrophils
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MS and irritable bowel syndrome correlate with what vitamin deficiency?
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D
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diseases assoc. with vitamin D deficiency?
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MS, IBS, Type I diabetes, rheumatoid arthritis and systemic lupus erythematosus
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primary role of vitamin K
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post-translational modification of various blood clotting factors
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forms of vitamin K
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K1(phylloquinone)-plants, egg yolk and liver
K2(menazuinone)-intestinal bacterial flora menadione-synthetic derivative |
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the most active natural form of vitamin K
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K1(phylloquinone)
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functions of vitamin K
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1. synthesis of prothrombin and blood clotting factors in liver-inactive to active
2. interaction of prothrombin with platelets-prothrombin to thrombin |
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cases of hypoprothrombinemia
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antibiotics, elderly, newborns and patients with obstructive jaundice(K requires bile to be absorbed)
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results of vitamin K toxicity
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hemolytic anemia and jaundice in infants
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why are newborns at risk for vitamin K deficiency?
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K does not cross the placental barrier and they have sterile intestines
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where do we find vitamin E?
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vegetable oils, seed embryos, grains, leafy vegetables, liver and eggs
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functions of vitamin E?
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antioxidant in the prevention of oxidation of cell components by molecular O2 and free radicals-E becomes oxidized
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RDA for vitamin E?
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10mg for men, 8mg for women
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why would the RDA of vitamin E increase?
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increase in the intake of polyunsaturated fatty acids-increased serum cholesterol-more free radicals
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vitamin E is linked to the decrease in what disease?
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heart disease-decreased risk of MI or death in men and women
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the least toxic lipid-soluble vitamin
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vitamin E
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PTH effect on hydroxylases in vitamin D pathway?
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incr. 1-hydroxylase-active form
decr. 24-hydroxylase-inactive form |
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Type II vitamin D-dependency rickets
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lack of receptors or impaired function
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