Parathyroid glands

Small glands that play a crucial role in regulating calcium levels in the blood.

Parathyroid glands are four small endocrine glands located on the posterior surface of the thyroid gland in the neck. Each gland is roughly the size of a grain of rice and functions primarily to produce parathyroid hormone (PTH), which is vital for maintaining proper calcium balance in the body. Additionally, PTH has a role in phosphate metabolism.

Terminologia Anatomica

glandulae parathyreoideae

System

Endocrine system

Function

The primary function of the parathyroid glands is to regulate calcium levels in the blood, which is essential for various physiological processes, including muscle contractions, nerve impulse transmission, and blood coagulation. When blood calcium levels drop, the parathyroid glands release PTH into the bloodstream. This hormone stimulates the release of calcium from bones, increases calcium absorption in the intestines by promoting vitamin D activation, and reduces calcium loss through the kidneys. This finely tuned mechanism ensures that the body maintains calcium homeostasis, preventing both hypocalcemia (low calcium levels) and hypercalcemia (high calcium levels), which can lead to various health issues.

Location

Parathyroid glands are situated on the posterior surface of the thyroid gland, with each gland typically located near the corners of the thyroid's lobe. The thyroid itself is located in the lower front of the neck, just below the Adam's apple, covering the trachea. Due to variability in human anatomy, the location of the parathyroid glands can sometimes differ, with some individuals having them located in the upper neck or even within the chest cavity, highlighting their migratory nature during fetal development.

Did You Know?

Parathyroid glands were named in the late 19th century, but they were not clearly identified until later due to their small size.
People can live normally with only one functioning parathyroid gland, showing the resilience and adaptability of the human body.
Diseases affecting the parathyroid glands can lead to conditions like hyperparathyroidism or hypoparathyroidism, each with distinct symptoms and treatments.
Parathyroid hormone was one of the first hormones discovered that regulates mineral balance in the body, emphasizing the importance of these glands in overall health.