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15 Cards in this Set
- Front
- Back
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plasma Ca is bound to (3)
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protein, i.e., albumin (40%)
citrate and phosphate (10%) |
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symptoms of hypocalcemia
general (2) neuronal (1) cardiac (2) |
general:
-learning retardation (chidlren) -apnea neuronal: -tetany (spasms, seizures, numbness, muscle cramps) cardiac: -long Q-T interval -reduced cardiac output |
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symptoms of hypercalcemia
general (5) neuronal (3) caridac (2) renal (3) |
general:
-fatigue -apathy -anorexia -delerium -coma neuronal: -headache -ICP -muscle weakness cardiac: -short Q-T interval -bradycardia renal: -polydipsia -polyuria -HTN |
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intracellular Ca is bound to (3)
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mitochondria
microsomes ER |
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targets of PTH (2)
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kidney
bone cells |
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effects of PTH on the kidney (3)
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increased Ca reabsorption at dct
increased PO4 excretion increased 1,25(OH)2D3 synthesis (PTH activates vitamin D synthesis) *PO4 binds Ca and lowers plasma [Ca]* |
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effects of PTH on bone cells (2)
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increased osteoclastic resorption via receptors on osteoblasts (only osteoblasts contain PTH receptors; send paracrine signals to osteoclasts)
increased Ca and PO4 in ECF and plasma |
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targets of vitamin D (2)
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intestine
bone |
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effect of vitamin D on the intestine
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increased Ca and PO4 absorption (24-48 hour response time)
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effects of vitamin D on bone (2)
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increased osteoclastic resorption via receptors on osteoblasts (paracrine singalling)
decreased PTH secretion (negative feedback mechanism) |
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vitamin D synthesis steps
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7-dehydrocholesterol (skin) + UV light --> cholicalciferol (Vit. D3-inactive form, blood) --> 25-OH cholicalciferol (measured via blood test, liver) --> 1,25(OH)2D3 (active form, kidney)
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osteoclast maturation is stimulated by
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RANK ligand
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bone resorption is inhibited by
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OPG (binds to RANK ligand receptors on premature osteoclasts to prevent osteoclast maturation)
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OPG is produced by
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osteoblasts
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ways to prevent bone fractures (5)
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adequate Ca and vitamin D
early bone mass accumulation bisphosphates (Fosamax) - inhibit osteoclast activity estrogen and estrogen receptor modulators pulsed PTH |
