Extracellular calcium is transported throughout the body via the blood vessels. Two primary factors are responsible for stabilizing blood calcium levels: the parathyroid hormone, in short PTH, which forms in the parathyroid glands, and vitamin D, which is synthesized in the liver and skin and converted into its active form, calcitriol, in the kidney. A third regulator is calcitonin, which forms in the thyroid gland. An interactive version of this Chalk Talk episode can be found at: […]