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23 Cards in this Set
- Front
- Back
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Vitamin A (retinol form)
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Fat soluble
required for: visual cycle, hormones needed for cell proliferation and differentiation (lymphocytes, epithelium, and osteoclasts) |
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Vitamin A deficiency
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night blindness
decreased resistance to infection (low lymphocytes) aberrant differentiation of epithelial cells in eyes fetal deformities |
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Vitamin A excess
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peeling, skin, bone demineralization, bone fragility, pain, fetal deformities
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What is the hormonal form of vitamin A
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the carboxylic acid form
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What is the form of vitamin A that is used for the visual cycle?
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11-cis-retinal
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what is the storage form of vitamin A?
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retinyl ester
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What is the dietary source of vitamin A?
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B-carotene
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What is the transport for of vitamin A?
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retinol (the alcohol)
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How do retinoids (retinoic acids) change gene transcription?
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a retinoid receptor protein dimerizes with another and then binds the gene element. When retinoid binds teh RRP, the transcription of gene is altered (it increases or decreases)
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How does vitamin A cause abnormal differentiation in the eye?
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mucous secreting epithelial cells become keratinizing squamous epithelial cells. This can result in xeropthalmia, bitot's spots, corneal changes that can result in blindness
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Vitamin D
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fat soluble, requires UV light
Required for: synthesis of 1,25(OH)2D2 or 3 (D2 or D3) |
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Vitamin D deficiency
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inadqequate mineralization of bones
adults: osteomalacia (bone fragility and pain) Children: ricketts, as above only with bone deformation |
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Vitamin D excess
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hypercalcemia causing Ca deposits and organ damage. Increased dimineralization of bone and bone fragility and pain
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Where is D2 made?
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from ergosterol in plant, fungal, and invertebrate cells
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Where is D3 made?
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from cholesterol in vertebrate skin cells
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In what two organs is vitamin D modified?
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the liver (C25) and the kidney (C1). Diseases of either my produce a deficiency
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How does the vitamin D hormone work?
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it binds the receptor protein in the nuclei of target cells and alters transcription of many genes
increases plasma calcium and phosphorus |
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How does vitamin D increase plasma calcium and phosphorus
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1) increases uptake of calcium by small intestine
2) increases release of CA and HPO4 by the bone: increases expession of RANK ligand by osteoblasts |
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niacin
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water soluble
needed for synthesis of NAD and NADPH *can be made endogenously from TrP |
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niacin deficiency
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pellegra: rough skin
3 D's: dermatitis, diarrhea, and dementia (death) S.A.D.= symptoms of ATP deficiet |
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what types of reactions are niacin enzymes used for?
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oxidation of carbs, lipids and amino acids, making ATP
if deficient, problems arise for cells (especially those that divide rapidly like skin cells) |
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riboflavin (B2)
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water soluble
needed for synthesis of FAD, FMN which are coenzymes for redox reactions and energy releasing pathways |
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riboflavin deficiency
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SAD
dermatitis, destruction of mucous secreting epithelial cells, glossitis, cheilosis (inflammation of lips, mouth), and corneal inflammation *usually not diet deficient, babies undergoing light therapy may need supplements |
