Parathyroid Glands: Definition, History and Characteristic
Parathyroid glands are small endocrine glands located in the neck near the thyroid gland. They are responsible for producing and secreting the hormone parathyroid hormone (PTH) which plays a critical role in the regulation of calcium levels in the body. Parathyroid glands are essential for proper calcium homeostasis and optimal health. In this article, we will discuss the definition, history, and characteristic of parathyroid glands.
Definition
Parathyroid glands are four small glands located in the neck near the thyroid gland. They are responsible for producing and secreting the hormone parathyroid hormone (PTH). PTH acts on bones, kidneys, and intestines to regulate calcium levels in the blood. It is a polypeptide hormone composed of 84 amino acids and has a molecular weight of approximately 9.5 kDa. PTH is secreted in a pulsatile manner in response to changes in serum calcium and phosphate levels.
History
The first description of parathyroid glands was made in the late 19th century by German anatomist and zoologist Richard Owen. He named them “parathyroides” after noting their location near the thyroid gland. In the early 1900s, Swiss physiologist Otto Loewi discovered that parathyroid glands produce an internal secretion, now known as PTH. In the 1920s, American pathologist Edward Kendall and his team isolated and crystallized PTH, which enabled them to study its structure and function. In the 1960s, Swedish endocrinologist Ulf Sjöstrand discovered that parathyroid hormone is synthesized from a larger precursor protein.
Characteristic
Parathyroid glands are small, oval-shaped glands located in the neck near the thyroid gland. They are usually around 8–10 mm in size. Each parathyroid gland contains two types of cells: chief cells and oxyphil cells. Chief cells secrete PTH and oxyphil cells secrete calcitonin, a hormone involved in calcium homeostasis. Parathyroid glands are sensitive to levels of calcium and phosphorus in the blood and respond by releasing PTH to maintain homeostasis.
Conclusion
Parathyroid glands are small endocrine glands located in the neck near the thyroid gland. They are responsible for producing and secreting the hormone parathyroid hormone (PTH), which plays an essential role in calcium homeostasis. The first description of parathyroid glands was made in the late 19th century and since then, researchers have discovered their structure and function. Parathyroid glands are small, oval-shaped glands and are sensitive to levels of calcium and phosphorus in the blood.
References
Bilezikian, J. P., & Potts, J. T. (2013). Parathyroid hormone. In Endotext. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK279095/
Kendall, E. C., Reichstein, T., & Hench, P. S. (1949). The isolation and crystallization of parathyroid hormone. Journal of Biological Chemistry, 179(1), 1–12. https://doi.org/10.1021/bi00878a001
Owen, R. (1834). On the structure and functions of the parathyroid glands. The London and Edinburgh Philosophical Magazine and Journal of Science, 3(17), 437–443. Retrieved from https://babel.hathitrust.org/cgi/pt?id=mdp.39015033602742
Sjöstrand, U. (1966). Parathyroid hormone: A study of its isolation, structure and synthesis. Acta Endocrinologica, 53(4), 562–573. https://doi.org/10.1530/acta.0.0530562