Role of Calcium in Bones
Typical body contains between 1-2kg of calcium, 99% of which is deposited in skeleton. If levels of calcium increase by 30% neurons and muscle cells lose responsiveness. An increase of 30% causes excitability to the point of convulsions. A 50% increase usually causes death. Hormones parathyroid hormone and calcitriol increases serum calcium. Calcitonin depresses serum calcium.