Define Tissue Distribution and Regulation of Calcium Concentration?
As already discussed, development and preservation of bone mass is quantitatively an important function of calcium. It should also be noted here that the calcium content of the body at birth is only 30 mg which increases to 1000-1200 g by adulthood through deposition of mineral in the skeleton. It is not surprising, then, that of 1200 g calcium found in an adult human, 99% is present in bones and teeth. The remaining 10% found in blood, extracellular fluid (ECF), muscles and other tissues, nevertheless plays an important role in vascular contraction, vasodilation, muscle contraction, nerve transmission and glandular secretions. The concentration of ionized calcium in blood plasma is very critical for their functions and therefore the plasma calcium is controlled within very narrow limits, the skeletal calcium providing a large reserve for doing this.