Calcium Homeostasis 0.0 / 5 ? BiologyEndocrinologyUniversityAll boards Created by: emmaCreated on: 09-12-13 14:18 Hypocalcium increases nerve excitability.. leading to tetany --> asphyxiation 1 of 24 Hypercalcaemia decreases neurotransmitter excitability... leading to cardiac arrhythmias, lethargy, death 2 of 24 3 causes of hypercalcaemia 54% hyperthyroidism, 34% malignancy associated, 12% other 3 of 24 3 ways homeostasis is maintained Bone - 500mg. Kidney, 10.8 filtration, 10.6 reabsorption. Intestines, 1g diet, 800mg faeces. 4 of 24 Free ionised calcium = ?mM 1.2 mM 5 of 24 sensing mechanisms sense changes in... Free ionised calcium levels 6 of 24 Where is PTH produced Chief cells in Parathyroid gland 7 of 24 Where is PTH cleaved Liver 8 of 24 PTH secretion is ? proportional to serum calcium inversely - signmoidal 9 of 24 Effects of VitD increase net intestinal Ca uptake from 200-600 mg/day, increase calbindin expression, increase serum Ca levels by increased bone resorption and renal reabsorption 10 of 24 Deficiency of Vit D can cause Rickets, secondary HPT and osteomalacia 11 of 24 Where is calcitonin produced parafollicular thyroidal c cells 12 of 24 what calcitonin do? decrease calcium after load 13 of 24 Oral calcium salts are.. calcium gluconate, calcium lactate, hydroxyapatite 14 of 24 injected calcium salts are calcium gluconate for hypocalcaemia tetany 15 of 24 Oral vitamin D3... t1/2=22hours, binds alpha globulin, treats rickets, osteodystrophy and HPT hypocalcaemia 16 of 24 Excess VitD3 can cause hypercalcaemia, osteoporosis, proteinuria, polyuria, nephrocalcinosis, vascular cacification 17 of 24 To treat hypercalcaemic crisis.. saline hydration, furosemide (Lasix) diuresis (Decrease calcium reabsorption in cTAL), calcitonin (decrease bone resorption) and bisphosphonates 18 of 24 Glucocorticoid treatment decreases intestinal ca absorption, decreases bone foration, increases renal extretion, may lead to osteoporosis 19 of 24 disphosphonates decrease bone turnover, bind hydroxyapatite 20 of 24 mithramycin decrease bone reabsorption, antibiotic in cancer treatment, treat hypercalcaemia and paget's at 1/10 of chemo dose 21 of 24 calcimimetics decreases PTH secretion, treats primary and secondary HPT, +VE allosteric modulator of CR 22 of 24 calcilytics increase PTH secretion, osteoporosis treatment, -ve allosteric modulator of CR (antagonist) 23 of 24 sodium cellulose phosphate oral, binds ca in gut, decreases intestinal absorption, may increase serum phosphate 24 of 24
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