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75 Cards in this Set
- Front
- Back
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Nystagmus
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Oscillations of the eyeball(s)
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Organic Toxic Psychosis
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A detrimental loss of abject reality which originated from an organic source
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Ataxia
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Uncontrolled Muscle Movements
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Thiamin Pyrophosphate (TPP)
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Active form of Thiamin, which is involved in the oxidative decarboxylation of alpha-ketoacids, PDH, alpha-KGDH reactions and the transketolase reaction
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what diseases result from a deficiency of Thiamin (B1)
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Beriberi
Wernicke encephalopathy - complex ophthalmoplegia, ataxia, and acute confusional state Wernicke-Korsakoff Syndrome - with persistent learning and memory deficits |
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Symptoms of B1 Deficiency
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Constipation
Appetite Suppression Nausea Peripheral Neuropathy Mental Depression Fatigue Cardiovascular and Muscular defects |
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what accounts for the loss of memory in Wernicke-Korsakoff Syndrome?
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Wernicke-Korsakoff Syndrome damages limbic system
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for what is riboflavin (B2) a precursor?
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Precursor for FAD/FADH2
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Why could infants with hyperbilirubinemia potentially experience flavin deficiencies?
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Riboflavin decomposes under light, and phototherapy is the treatment for hyperbilirubinemia
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-emia
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suffix meaning in the blood
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-urea
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suffix meaning in the urine
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kernicterus
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bilirubin crosses blood/brain barrier and binds to neurons
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what is B1?
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thiamin
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what is B2?
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riboflavin
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what is B3?
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niacin
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what disease results from a deficiency of niacin (B3)?
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pellagra
(italian word for dry skin) |
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what are the symptoms of niacin deficiency?
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**diarrhea, dementia, dermatitis**
(3 D's) also weight loss |
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what treatments can cause B3 (niacin) deficiency?
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isoniazid treatment for TB
nicotinic acid treatment for plasma cholesterol |
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what is B5?
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pantothenic acid
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for what is pantothenic acid (B5) a precursor?
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coenzyme a (CoA)
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what is B6?
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group of molecules including pyridoxal, pyridoxamine, pyridoxine and pyridoxal phosphate (active form)
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what converts pyridoxal, pyridoxamine, and pyridoxine to pyridoxal phosphate?
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pyridoxal kinase (which requires zinc)
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for what is pyridoxal phosphate (PLP) used?
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cofactor in transamination reactions
glycogen phosphorylase GAD (GABA synthesis) |
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when does B6 intake need to be increased?
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during pregnancy and lactation
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what treatments cause B6 (pyridoxal phosphate) deficiency?
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isoniazid treatment for TB
penicillamine treatment for rheumatoid arthritis (both complex with PLP) |
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for what is biotin used?
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cofactor in carboxylation reactions
(e.g. acetyl-CoA carboxylase and pyruvate carboxylase) |
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what treatment can lead to biotin deficiency?
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strong antibiotics (since intestinal bacteria synthesize biotin)
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why do raw eggs cause biotin deficiency?
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avidin, a protein in raw eggs, strongly complexes biotin leading to deficiencies
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what is vitamin B12?
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cobalamin
found bound to protein as methylcobalamin or 5'deoxyadenosylcobalamin |
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how is B12 absorbed?
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hydrolyzed from protein in stomach by gastric acid or in intestines by trypsin
bound to intrinsic factor carried to ileum and absorbed transported to liver in blood bound to transcobalamin II |
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by what is B12 cleaved from the protein which carries it?
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gastric acid in stomach
or trypsin in intestines |
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by what is B12 carried to the ileum and absorbed?
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intrinsic factor
(from parietal cells of stomach) |
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what two reactions require B12?
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conversion of propionyl-CoA to succinyl-CoA
converting homocysteine to methionine (transferring methyl group from N5-THF to OH-cobalamin) |
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what enzymes require B12?
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methylmalonyl-CoA mutase
methionine synthase |
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why is methionine synthase such an important enzyme requiring B12?
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N5-THF conversion to DHF
(if this doesn't happen, cells can't divide, since it's important in nucleotide metabolism) |
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what happens as the result of a buildup in homocysteine?
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thiolates proteins, leading to their degradation
inhibits lysyl oxidase (which makes mature collagen) increases thrombosis and cardiovascular disease |
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what results from intrinsic factor deficiencies?
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B12 deficiency
pernicious anemia (loss of blood cell production by marrow) |
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what are the symptoms of pernicious anemia?
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numbness
tingling weakness sore smooth tongue anorexia diarrhea pallor of the skin and mucous membranes |
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what clinical findings are present in pernicious anemia patients?
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chronic progressive anemia of older adults
low RBC counts low hemoglobin numerous macrocytic erythrocytes predominant numbers of megaloblasts |
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what are megaloblasts?
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abnormal, nucleated red blood cells
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for what is folic acid important?
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1-carbon transfer reactions
most importantly in dTMP synthesis, since amino acids can be acquired from the diet and purine nucleotide salvage is so efficient |
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what type of anemia is indicative of folic acid deficiency?
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megaloblastic and macrocytic anemia
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what treatments can impair folate absorption?
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anticonvulsants
oral contraceptives |
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what is vitamin C?
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ascorbic acid
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what is the major function of ascorbic acid?
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cofactor in hydroxylation of proline residues of collagen
also involved in catabolism of tyrosine, synthesis of epinephrine, synthesis of bile acids, and steroidogenesis |
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what disease results from vitamin C deficiency?
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scurvy
deficiencies result primarily from poor diet |
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what vitamins are water soluble?
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thiamine (B1)
riboflavin (B2) niacin (B3) pantothenic acid (B5) PLP (B6) biotin (B7) folic acid (B9) cyanocobalamin (B12) ascorbic acid (C) Biotin (B7) folic acid (B9) |
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what is B7?
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biotin
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what is B9?
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folic acid
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what vitamins are lipid soluble?
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retinol (A)
cholecalciferol (D) tocopherols (E) phylloquinone (K) |
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what is vitamin A?
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retinol
retinaldehyde retinoic acid |
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from what is retinol derived?
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beta-carotene in intestine
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by what enzyme is retinol converted to retinal and back?
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retinaldehyde reductase
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by what class of enzymes is retinal oxidized to retinoic acid?
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retinaldehyde dehydrogenases
(RALDHs) |
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by what is retinol transported from the liver?
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bound to aporetinol binding protein (RBP)
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by what means does plasma transport of vitamin A occur?
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bound to albumin
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what binds vitamin A within extrahepatic cells?
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cellular retinol binding protein (CRBP)
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what forms rhodopsin (visual purple)?
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11-cis-retinal
and scotopsin |
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with what is rhodopsin coupled?
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G-protein called transducin
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explain the process of light reception by rhodopsin
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when exposed, 11-cis-retinal is converted to all-trans-retinal
conformational change activates transducin increased GTP binding activates cGMP phosphodiesterase cGMP maintains Na+ channels in the open state drop in cGMP closes channels and leads to hyperpolarization of rod cell |
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what happens in deficiency of vitamin A?
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night blindness
increased susceptibility to infection and cancer |
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what happens in severe deficiency of vitamin A?
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progressive keratinization of the cornea
(xerophthalmia) |
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what is xerophthalmia?
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progressive keratinization of the cornea
caused by severe vitamin A deficiency |
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in what is vitamin D involved?
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calcium homeostasis
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what is caused by a deficiency of vitamin D?
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rickets in children
osteomalacia in adults |
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what is the progression of vitamin D conversions?
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cholecalciferol -> 25-OH cholecalciferol in liver
25-OH -> calcitriol in kidney |
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what is calcitriol?
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1,25-dihydroxycholecalciferol
hormone that functions to regulate serum calcium and phosphorous levels in concert with PTH and calcitonin |
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what is vitamin E?
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mixture of compounds known as tocopherols
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what is the major storage site for vitamin E?
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adipose tissue
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what is the major function of vitamin E?
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antioxidant
scavanges peroxy free radicals, then is conjugated to glucuronate, and excreted in bile |
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what are the two possibilities for vitamin E after it has scavenged peroxy free radicals?
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conjugated to glucuronate and excreted in bile
transfers electrons to vitamin C and regenerated |
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what are the three forms of vitamin K?
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phylloquinone - found in plants
menaquinone - bacterially synthesized menadione - synthetic form in supplements |
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what is the major function of vitamin K?
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cofactor in generation of gamma-carboxy-glutamate residues found in clotting factors
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what is the function of gla residues in clotting factors?
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chelates calcium
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when are vitamin K deficiencies seen?
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maladsorptive diseases
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