Calcium Metabolism, Vitamin D, Parathyroid Hormone and CalcitoninCalcium-ImportanceKey role played by calcium in:1.!eletal muscle contraction".Cardiac muscle contraction#.mooth muscles contraction$.%lood clottin&'.(ransmission o) ner*e impulsesDistribution o) Calcium in the %ody+ distribution o) total body calcium1. ,C- - ..1+". Intracellular / 1+#. %ones / 0est 1er*e as 0eser*oirs2Calcium Distribution in ,C-Calcium ,3chan&e %et4een Di5erent (issue Compartments1000%one 6nd Its 0elation to ,3tracellular Calcium%one 7 matri3 1colla&en 8 &round substance2 8 salts 1mostly hydro3yapetite, some amorphous2,3chan&eable calcium / readily mobili9able salts li!e calcium phosphate and other amorphous salts