A number of vital functions in human body are controlled by biochemical substances, called hormones, which are chemical messengers released by either ductless or ducted glands directly into the blood stream or through ducts. Of all the hormone secreting glands in the body, the parathyroid gland is the smallest which is embedded in the thyroid gland or located on the rear side of it in the neck. There are four parathyroid glands located on the posterior side of the thyroid, measuring only about the size of a rice grain.
Because of the very small size, these endocrine glands weigh as low as 20mg or as high as 40mg. Usually, these are four in number, arranged in two pairs-one above and the other below-but some individuals have also been reported to have 6, 8 or even more. The two glands lying towards the head are termed as the superior parathyroid glands, while the other two lying on the lower side are known as the inferior parathyroid glands. Though the parathyroid glands are named after their close proximity with the thyroid gland, their functions are completely different from that of the neighbouring endocrine organ. Nervous and muscular systems are very sensitive to the concentration of calcium in the body that has to be maintained in a narrow range for their proper functioning. The hormone secreted by parathyroid gland (named after the gland as ‘parathyroid hormone’ or simply “parathormone”) is responsible for the maintenance of phosphate and calcium homeostasis in the body, and is functionally opposed to calcitonin.
Fun Facts on Parathyroid Glands
Though there are no pills or medications to cure the diseases of parathyroid gland, surgery and some other treatment measures have shown promising results.
Most of the parathyroid problems present themselves in their advanced stages, and some patients will not complain of any symptoms, until they are identified during routine diagnostic procedures.
Often the medical fraternity get confused with the diseases of the parathyroid gland and the blood calcium levels, as neither of these the conditions (diseases and calcium levels) have ever been found to synchronize with each other.
Most of the patients suffering from parathyroid disease have fluctuating blood calcium levels both in blood and bony structures.
Parathyroid glands are small endocrine glands in the neck of humans and other tetrapods that produce parathyroid hormone. Humans usually have four parathyroid glands, variably located on the back of the thyroid gland — considerable variation exists. Parathyroid hormone and calcitonin (one of the hormones made by the thyroid gland) have key roles in regulating the amount of calcium in the blood and within the bones.
Parathyroid glands share a similar blood supply, venous drainage, and lymphatic drainage to the thyroid glands. Parathyroid glands are derived from the epithelial lining of the third and fourth branchial pouches, with the superior glands arising from the fourth pouch, and the inferior glands arising from the higher third pouch. The relative position of the inferior and superior glands, which are named according to their final location, changes because of the migration of embryological tissues.