True of the following

Parathormone - hormone synthesized and released into the bloodstream by the parathyroid glands; regulates phosphorus and calcium in the body and functions in neuromuscular excitation and blood clotting. After ingestion of substantial amounts of calcium, the sho term control that prevents calcium spiking in the serum is absorption by the bone matrix. After about an hour, PTH will be released and not peak for about 8 hours. The PTH is, over time, a very potent regulator of plasma calcium, and controls the conversion of vitaminD into its active form in the kidney. The parathyroid glands are located behind the thyroid and produce the parathyroid hormone in response to low calcium levels.Ref: Ganong&;s review of medical physiology; 24th edition; page no:-377