Where are the parathyroid glands located?

The parathyroid glands are two pairs of small glands on the posterior aspect of the thyroid lobes. The superior parathyroids are constant in position at the thyroid's mid-posterior border, while the inferior parathyroids are variable, often near the lower pole.

What is the function of the parathyroid glands?

They secrete parathormone (PTH), which increases blood calcium levels by mobilizing calcium from bone, enhancing calcium reabsorption in the kidneys, and promoting intestinal calcium absorption.

How do the superior and inferior parathyroid glands differ?

They differ in location, blood supply, and embryonic origin. The superior glands have a constant position, are supplied by the superior parathyroid artery, and come from the 4th pharyngeal pouch. The inferior glands have a variable position, are supplied by the inferior thyroid artery, and come from the 3rd pharyngeal pouch.

What are the clinical conditions associated with parathyroid dysfunction?

Two main disorders are hypoparathyroidism, often post-surgical and causing low calcium and tetany, and hyperparathyroidism, usually from a tumor and leading to bone softening and kidney stones.

What is the blood supply to the parathyroid glands?

The superior parathyroid is supplied by the superior parathyroid artery, while the inferior parathyroid is supplied by a branch of the inferior thyroid artery, which serves as a surgical landmark.

How are the parathyroid glands innervated?

They receive sympathetic innervation from cervical sympathetic ganglia, which is vasomotor. Hormone secretion is regulated by serum calcium levels, not nerve signals.

What are the key cells in the parathyroid glands?

The main cells are chief cells, which secrete parathormone to regulate calcium, and oxyphil cells, a minor population with unknown function.

Parathyroid Glands – Location & Calcium Control

❓ Frequently Asked Questions