Parathyroid and Calcium Homeostasis
Calcium is an essential ion that is regulated in the body very tightly so that essential bodily functions are not affected by lack or excess of this vital element. Calcium that is present in the diet is absorbed in the gut in the presence of Vitamin D, and whose expression is monitored constantly through receptors which feed this information to the four tiny brown glands embedded into the thyroid gland in the neck. Parathyroid glands produce parathyroid hormone, which is released into the blood stream whenever calcium fluctuations happen. High calcium suppresses it, low calcium stimulates it. Parathyroid glands produce their effects through regulating vitamin D activation in the gut as well as by affecting the bone forming cells (osteoblasts) and bone degrading cells (osteoclasts). Bone is called upon to release calcium through osteoclastic activity mediated by parathyroid hormone and when the calcium level is restored, bone can claim the lost calcium back. This is orchestrated very finely and again is easy to diagnose through well planned tests. Nowadays we see unnecessary parathyroid surgery due to improper diagnosis. Through careful history, appropriate tests etc one can determine whether a parathyroid tumor formation was a defence mechanism of the body or cancerous and take action appropriately.