Calcium plays a very important role in the formation of bones. Write on the role of endocrine glands and hormones responsible for maintainim calcium homeostasis.
The endocrine glands and hormones that are responsible for maintaining calcium homeostasis, are thyroid and parathyroid glands and their associated hormones an calcitonin and Parathyroid Hormone (PTH).
(i) Parathyroid glands are the glands developed from the endoderm of the embryo The cells of parathyroid glands are of two types, i.e., chief cells and oxyphil cells. Thr chief cells of the parathyroid glands secrete parathyroid hormone (PTH).
This hormone (PTH) is involved in regulating calcium and phosphate balance betweer the blood and other tissue. It mobilises the release of calcium into the blood from bones. PTH increases calcium reabsorption by the body organs like intestine anc kidneys.
(ii) Thyroid gland is the largest endocrine gland located anterior to the thyroid cartilage o. the larynx in the neck. This gland plays a vital role in maintaining calcium homeostasis It releases thyroculcitonin hormone produced by the parafollicular cells, also called 'C cells.
This hormone is secreted when the calcium level in blood gets high. It is a 32 aminc acid peptide hormone that lowers the calcium level by suppressing release of catciurr ions from the bones. Thus, calcitonin has an action opposite to that of the parathyroic hormone on calcium homeostasis.