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67 Cards in this Set
- Front
- Back
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vitamin A function
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antioxidant
constituent of visual pigments |
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vitamin A deficiency
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night blindness
dry skin squamous metaplasia of specialized epithelia |
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vitamin A excess
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arthralgias, fatigue, headaches, skin changes, sore throat, alopecia;
teratogenic (cleft palate, cardiac abnormalities) |
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vitamin A sources
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liver
leafy vegetables |
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vitamin A
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retinol
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vitamin B1
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thaimine
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vitamin B1 function
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thiamine pyrophosphate (TPP) is cofactor for:
pyruvate dehydrogenase (glycolysis) a-ketoglutarate dehydrogenase (TCA) transketolase (HMP shunt) branched-chain aa dehydrogenase |
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vitamin B1 deficiency
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wernicke-korsakoff (confusion, ophthalmoplegia, ataxia + memory loss, confabulation, personality change);
dry beriberi (polyneuritis, symmetrical muscle wasting); wet beriberi (dilated cardiomyopathy, edema) |
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vitamin B2
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riboflavin
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vitamin B2 function
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FAD, FMN:
cofactor in oxidation and reduction |
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vitamin B2 deficiency
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cheilosis (inflammation of lips, scaling and fissures at corners of mouth);
corneal vascularization |
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retinol
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vitamin A
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thiamine
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vitamin B1
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riboflavin
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vitamin B2
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vitamin B3
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niacin
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vitamin B3 function
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NAD, NADP: redox reactions;
derived from tryptophan; synthesis requires vitamin B6 |
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vitamin B3 deficiency
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glossitis
pellagra (diarrhea, dermatitis, dementia) |
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causes of vitamin B3 deficiency
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hartnup dz (decreased tryptophan absorption);
malignant carcinoid sx (increased tryptophan metabolism); INH (decreased vitamin B6) |
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vitamin B3 excess
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facial flushing
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niacin
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vitamin B3
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vitamin B5
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pantothenate
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vitamin B5 function
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essential component of CoA (cofactor for acyl transfers);
fatty acid synthase |
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vitamin B5 deficiency
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dermatitis
enteritis alopecia adrenal insufficiency |
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pantothenate
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vitamin B5
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vitamin B6
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pyridoxine
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vitamin B6 function
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converted to pyridoxal phosphate - cofactor in transamination, decarboxylation rxns, glycogen phosphorylase, heme synthesis;
required for synthesis of niacin from tryptophan |
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vitamin B6 deficiency
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convulsions
hyperirritability peripheral neuropathy |
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induce vitamin B6 deficiency and causing peripheral neuropathy
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INH
oral contraceptive |
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pyridoxine
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vitamin B6
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vitamin B12
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cobalamin
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cobalamin
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vitamin B12
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vitamin B12 function
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cofactor for homocysteine methyltransferase and methylmalonyl-CoA mutase
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vitamin B12 sources
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animal products
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vitamin B12 deficiency
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macrocytic, megaloblastic anemia;
neurologic symptoms (paresthesias, subacute combined degeneration) due to abnormal myelin; prolonged deficiency leads to irreversible system damage |
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causes of vitamin B12 deficiency
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sprue
enteritis diphyllobothrium latum lack of intrinsic factor absence of terminal ileum |
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folic acid function
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THF - coenzyme for 1-carbon transfer/methylation reactions;
important for synthesis of nitrogenous bases in DNA and RNA |
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folic acid sources
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green leafy vegetables
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folic acid deficiency
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macrocytic, megaloblastic anemia;
no neurologic symptoms; mc vit def in US - seen in alcoholism and pregnancy |
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causes of folic acid deficiency
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phenytoin
sulfonamides MTX |
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biotin function
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cofactor for carboxylation enzymes:
pyruvate carboxylase (pyruvate --> OAA); acetyl-CoA carboxylase (acetyl-CoA --> malonyl-CoA); propionyl-CoA carboxylase (propionyl-CoA --> methylmalonyl-CoA) |
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causes of biotin deficiency
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antibiotic use
excessive ingestion of raw eggs |
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biotin deficiency
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relatively rare
dermatitis alopecia enteritis |
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vitamin C
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ascorbic acid
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ascorbic acid
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vitamin C
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vitamin C function
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antioxidant, also:
facilitates iron absorption (keeps reduced to Fe2+); hydroxylation of proline and lysine in collagen synthesis; dopamine b-hydroxylase (dopamine --> NE) |
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vitamin C sources
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fruits and vegetables
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vitamin C deficiency
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scurvy: swollen gums, bruising, anemia, poor wound healing
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D2
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ergocalciferol: ingested from plants, used as pharmacologic agent
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D3
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cholecalciferol: consumed in milk, formed in sun-exposed skin
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25-OH D3
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storage form
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1,25-(OH)2 D3
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calcitriol: active form
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vitamin D function
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increase intestinal absorption of Ca and phosphate;
increase bone resorption |
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vitamin D deficiency
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rickets in children
osteomalacia in adults hypocalcemic tetany |
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vitamin D excess
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hypercalcemia
hypercalciuria loss of appetite stupor |
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cause of vitamin D excess
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sarcoid (increased activation of vitamin D by epithelioid macrophages)
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cause of vitamin D deficiency
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dark skinned purely breast fed infants
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vitamin E function
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antioxidant: protects erythrocytes and membranes from free-radical damage
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vitamin E deficiency
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increased fragility of rbcs (hemolytic anemia);
muscle weakness; neurodysfunction |
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vitamin K function
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catalyzes g-carboxylation of glutamic acid residues on various proteins concerned with blood clotting (factors II, VII, IX, X, protein C and S)
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vitamin K sources
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synthesized by intestinal flora
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vitamin K deficiency
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neonatal hemorrhage with increased PT and aPTT but normal bleeding time
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causes of vitamin K deficiency
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sterile neonate intestines (given injection at birth);
prolonged use of broad-spectrum antibiotics |
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zinc function
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essential for activation of 100+ enzymes;
zinc fingers (transcription factor motif) |
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zinc deficiency
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delayed wound healing
hypogonadism decreased adult hair may predispose to alcoholic cirrhosis |
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specific iron deficiency symptoms
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dysphagia
koilonychia |
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kwashiorkor
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protein malnutrition resulting in skin lesions, edema, liver malfunction;
small child with swollen belly |
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marasmus
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energy malnutrition resulting in tissue and muscle wasting, loss of subcutaneous fat, and variable edema
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