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40 Cards in this Set
- Front
- Back
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What are the top 5 abundant elements in the environment?
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Iron
Aluminium Silica Oxygen Calcium |
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Where is 99% of the body's calcium stores found?
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In the teeth and bones
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What does the body do if the extracellular levels of calcium drop?
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Takes calcium from the bones
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What form is calcium absorbed in?
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Ionic form
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Where is calcium absorbed through active transport and what is it controlled by?
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Duodenum and proximal jejunum
1,25 dihydroxyvitamin D |
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What is the transport protein that carries caclium through the cell wall?
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Calbindin
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What regulates calbindin?
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Vitamin D
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Passive transport of calcium occurs where and what is it dependent on?
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Entire length of small intestine and is based on high levels of calcium outside of the intestines
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What factors inhibit absorption?
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Oxalates
Phytates Other 2+ cations fat malabsorption Phosphates - soft drinks Some medications Hypochlorhydria Ageing |
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What factors enhance absorption?
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Lactose
Vitamin D Low calcium intake Acidic Ph Growth Pregnancy Lactation Exercise |
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What % of calcium is transported via proteins such as albumin?
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40%
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What % of calcium is transported via sulphate, citrate or phosphate
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10%
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What are the 3 ways that calcium is excreted from the body?
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Urine
Faeces Skin |
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What is the urinary loss of calcium per day?
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100-200mg
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What factors increase urinary excretion?
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Sodium
Protein Boron + Magnesium Caffeine |
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What factors decrease urinary excretion of calcium?
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Phosphorus
Potassium Magnesium Boron |
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What two conditions reduce the amount of calcium excreted in the urine?
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HRT for post menopausal women
Growth Periods |
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What condition increases calcium excretion?
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Menopause
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What are the approximate losses of calcium through faeces per day?
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170mg
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What conditins or foods increase faecal calcium excretion?
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Fibre
Phytates Oxalates Magnesium Fat Malabsorption |
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What amount of calcium is loss through skin and sweat per day?
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15mg
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What increases the amount of calcium lost via the skin?
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Exercise
Can go to 50-100mg per day |
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What foods increase calcium excretion and where is it excreted?
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Protein from animal products
Via the urine |
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What hormones increase calcium excretion?
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PTH deficiency
Vitamin D |
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What is hypercalciuria?
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Elevated calcium in the urine
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What are H2 blockers?
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A class of drugs that block stomach acid secretion?
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What are H2 blockers?
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A class of drugs that block stomach acid secretion?
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What does the calcium that is not in the bone do?
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Cell signalling
Nerve pulse transmission Hormone secretion Muscle contraction Blood clotting Calcium regulation |
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What form is calcium in the bones?
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Hydroxyapatite
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What is the formula for hydroxyapatite?
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Ca5(OH)(PO4)3
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What is an osteoblast?
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creater of bone cell
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What is an osteoclast?
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Destroyer of bone cells
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What is hypotonia?
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Low muscle tone
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What are the elements needed to form bone?
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Osteoblasts
calcitriol Collagen Ground substance (Chondroitin sulphate) |
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What are the substances that osteoclasts release to break down bone?
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Citric acid
Lactic acid |
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What muscle action is calcium crucial for?
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Contraction
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How does calcium create muscle contraction?
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Action potential ->
Calcium released as ca2+-> calcium binds to troponin-> removes blocking action of tropomysin-> Contraction occurs-> After action potential ends ca2+ removed-> contraction stops |
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What is familial hypocalciuric hypercalcaemia?
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A family disease which causes PTH to perceive low levels of calcium and oversecrete, thereby increasing calcium uptake
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Which neurotransmitters require calcium at the synaptic cleft?
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Blood vessel constriction/dilation
secretion of hormones |
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What is the intracellular protein that binds with calcium ions to either inhibit/excite physiological responses in hormones?
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calmodulin
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