KJZ Vitamin Functions & Deficiencies
About this set
Created by:
kzachari on May 20, 2011
Subjects:
medical school, first aid, step 2, usmle
Description:
Table 2.17-7 from First Aid for the USMLE Step 2 CK plus extra information on function
Classes:
Pass Whisperer, Medical Students sharing helpful flashcards
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30 terms
Terms | Definitions |
|---|---|
 Vitamin A fxn | Antioxidant constituent of visual pigments; needed for specialized tissue cell differentiation (pancreatic, mucus-secreting). |
| Vitamin A def | Night blindness, dry skin. |
| Vitamin B1 (thiamine) fxn | Cofactor for pyruvate dehydrogenase (glycolysis), alpha-ketoglutarate dehydrogenase (TCA), transketolase (HMP), and branched chain AA dehydrogenase |
| Vitamin B1 def | Impaired glucose breakdown leads to ATP depletion especially in highly aerobic tissues (brain, heart); causes: - Wernicke-Korsakoff syndrome (confusion, opthalmoplegia, focal hemorrhage in mamillary bodies), - beri-beri (dry-polyneuritis, muscle wasting; wet-dilated cardiomyopathy, edema). |
| Vitamin B2 (riboflavin) fxn | Cofactor in oxidation and reduction. |
| Vitamin B2 def | Cheilosis (inflammation of lips with scalin and fissures at corners of mouth), corneal vascularization, angluar stomatitis. |
| Vitamin B3 (niacin) fxn | Constituent of NAD+, NADP+; derived from tryptophan; synthesis requires B6. |
| Vitamin B3 def | Glossitis, pellagra (diarrhea, dermatitis, dementia); can be caused by INH (decreased B6) or malignant carcinoid syndrome (increased tryptophan metabolism). |
| Vitamine B5 (pantothenate) fxn | Component of CoA and fatty acid synthesis. |
| Vitamin B5 def | Dermatitis, enteritis, alopecia, adrenal insufficiency. |
| Vitamin B6 (pyridoxine) fxn | Converted to pyridoxal phosphate, cofactor in transamination, decarboxylation, glycogen phosphorylase, cystathionine and heme synthesis; required for niacin synthesis |
| Vitamin B6 def | Convulsions, hyperirritability, peripheral neuropathy, sideroblastic anemia, required during admin of INH. |
| Vitamin B12 (cobalamin) fxn | Cofactor for homocysteine methyltransferase |
| Vitamin B12 def | Macrocytic megaloblastic anemia, hypersegmented PMNs, neurologic sx (paresthesias, subacute combined degeneration, optic neuropathy), glossitis, increased levels of homocysteine and methylmalonic acid. |
| Vitamin C fxn | Antioxidant; facilitates iron absorption; necessary for proline and lysine hydroxylation in collagen synthesis; necessary for dopamine beta-hydroxylase. |
| Vitamin C def | Scurvy: swollen gums, anemia, poor wound healing. |
| Vitamin D fxn | Increases intestinal absorption of calcium and phosphate; increases bone resorption. |
| Vitamin D def | Rickets in children (bending bone); Osteomalacia (soft bone) and hypocalcemic tetany in adults. |
| Vitamin E fxn | Antioxidant protects erythrocytes and membranes from free-radical damage. |
| Vitamin E def | Increased erythrocyte fragility leads to hemolytic anemia, muscle weakness, neurodysfunction. |
| Vitamin K fxn | Catalyzes gamma-carboxylation of glutamic acid residues on blood clotting proteins. |
| Vitamin K def | Neonatal hemorrhage with normal bleeding time, increased PT and PTT. |
| Biotin fxn | Cofactor for carboxylation enzymes. |
| Biotin def | Dermatitis, alopecia, enteritis; caused by antibiotic use or excessive RAW EGG ingestion. |
| Folic acid fxn | Converted to THF, coenzyme for 1-carbon transfer (methylation) reactions. |
| Folic acid def | THE MC VIT DEFICIENCY IN THE US; Sprue, macrocytic megaloblastic anemia, no neurologic symptoms; increased homocysteine, normal methylmalonic acid |
| Magnesium def | Weakness, nuscle cramps, exacerbation of hypocalcemic tetany, CNS hyperirritability leading to tremors, choreathetoid movement. |
| Selenum def | Keshan disease (cardiomyopathy). |
| Zinc fxn | Essential for activity of 100+ enzymes; needed for zinc finger transcription factor motif. |
| Zinc def | Delayed wound healing, hypogonadism, decreased adult hair, dysgeusia, anosmia. |
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