ABSTRACT
Blood Reactions. There is a continual series of interactions among the calcium levels in the blood, calcium found within a cell, and calcium stored in the bones. The parathyroid glands, together with vitamin D and calcitonin, are involved in calcium and phosphate metabolism in the body. They regulate the deposition and resorption of calcium and phosphate in bone. The blood levels of calcium and phosphate act, in turn, as feedback regulators of the secretion of parathyroid hormones and calcitonin.
