Term
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Definition
β-carotene cleaved in intestine by β-carotene dioxygenase retinal.
Retinal retinol
By retinaldehyde reductase,
____ requiring enzyme within the intestines.
Retinol is esterified to palmitic acid chylomicrons. liver storage as a lipid ester within lipocytes |
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Term
| cellular retinol binding protein (CRBP) |
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Definition
| In extrahepatic tissues retinol is bound to |
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Term
| aporetinol binding protein (RBP) |
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Definition
From liver to extrahepatic tissues
Binding of hydrolyzed retinol to |
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Definition
Rhodopsin or visual purple scotopsin + 11-cis-retinal
Coupled to a specific G-protein called |
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Definition
| appears to be responsible for initiating the closure of the channels |
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Term
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Definition
deficiency in this vitamin leads to Undernutrition or as a conditioned deficiency in malabsorption of fats.
Impaired vision, particularly in reduced light (night blindness).
Xerophthalmia (dry eye dryness of the conjunctivae (xerosis) small opaque plaques (Bitot spots) keratomalacia total blindness.
Upper respiratory passages and urinary tract squamous metaplasia secondary pulmonary infections, & renal and urinary bladder stones.
Hyperplasia and hyperkeratinization of the epidermis follicular or papular dermatosis.
Immune deficiency higher mortality rates from common infections such as measles, pneumonia, and infectious diarrhea |
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Definition
| this condition leads to headache, vomiting, stupor, and papilledema, symptoms also suggestive of brain tumor |
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Term
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Definition
treated with retinoic acid or its derivatives
Mild By topical application of Tretinoin (all trans retinoic acid) not used systemically as toxic
Severe oral isotretinoin(13-cis retinoic acid)
Chronic disease high amounts of β-carotene in diet decreased incidence of Heart disease and lung and skin cancer;
Decreased risk of macular degeneration and cataracts |
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Term
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Definition
what vitamin does this describe?Steroid hormone
Biologically active form is 1,25-dihydroxy vitamin (1,25-(OH)2D3 or calcitriol).
Functions primarily to regulate calcium and phosphorous homeostasis
Sources –
Diet Ergocalciferol and cholecalciferol |
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Term
| cholecalciferol (vitamin D3) |
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Definition
| In the skin 7-dehydrocholesterol is converted to ? following uv irradiation |
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Term
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Definition
| when vitamin D binds to a ? it can be transported to liver |
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Term
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Definition
Conversion of 25(OH)D to 1,25(OH)2D by ? in the kidney;
biologically this is the most active form of vitamin D |
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Term
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Definition
| this condition increases parathyroid hormone (PTH), and activates α1-hydroxylase |
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Term
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Definition
| directly activates α1-hydroxylase |
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Term
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Definition
Which vitamin is the following describing? Collaborates with PTH in the mobilization of calcium from bone
Effects on bone depend on plasma levels of calcium.
Hypocalcemia collaborates with PTH in resorption of calcium and phosphorus from bone
Required for normal mineralization of epiphyseal cartilage & osteoid matrix.
Increased synthesis of calcium-binding proteins osteocalcin & osteonectin in osteoid matrix may play a role |
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Term
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Definition
a vitamin D deficiency that leads to Infants Present with craniotabes, excess of osteoid frontal bossing and a squared appearance to the head.
Deformation of the chest "rachitic rosary" & pigeon breast deformity). spine, pelvis, and long bones (e.g., tibia lumbar lordosis and bowing of the legs |
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Term
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Definition
| In adults vitamin D deficiency deranges normal bone remodeling, inadequately mineralized, excess of persistent osteoid causes this condition |
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Definition
Mixture of several related compounds known as tocopherols.
which is the most potent? |
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Definition
Absorbed from the intestines--> chylomicrons--> tissues--> liver through chylomicron remnant uptake.
Liver can export vitamin E in VLDLs.
Due to lipophilic nature-->accumulates in cellular membranes, fat deposits and other circulating lipoproteins.
The major site of vitamin E storage is in ? |
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Term
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Definition
Vitamin E is an antioxidant that scavenges free radicals formed in redox reactions throughout the body
and plays a role in termination of free radical-generated lipid peroxidation chain reactions, particularly in cellular and subcellular membranes that are rich in polyunsaturated lipids.
Complemented by _____ whic is essential for the activities of glutathione peroxidase and thioredoxin reductase |
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Term
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Definition
the following describes which vitamin; Cofactor for liver microsomal carboxylase γ-carboxyglutamates.
Clotting factors II, VII, IX, and X & prothrombin
Carboxylation calcium-binding sites calcium-dependent interaction of clotting factors with phospholipid surface generation of thrombin
Proteins C and S also require γ-carboxylation
γ-carboxylation of osteocalcin facilitates binding to calcium |
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Term
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Definition
which vitamin does this describe? Majority is synthesized by bacteria in the large intestine.
Dietary sources include the photosynthetic (green) parts of plants.
No RDA but 70-140 mg/day is recommended as adequate level; Prolonged administration can cause hemolytic anemia and jaundice in new born |
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