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Human Body Study

Parathyroid Glands

Four tiny glands embedded in the back of the thyroid — separate from it in function, despite the shared location.

The endocrine system A stylised body with the eight endocrine glands placed at their anatomical positions: hypothalamus, pituitary, pineal, thyroid, parathyroids, adrenals, pancreatic islets and gonads. Each label links to the article for that gland. Hypothalamus Pituitary gland Pineal gland Thyroid gland Parathyroid glands Adrenal glands Pancreatic islets Gonads The endocrine glands at their anatomical positions — schematic, not to scale.

What they produce

Section titled “What they produce”

Parathyroid hormone (PTH) — the body’s main hormone for raising blood calcium.

What they do

Section titled “What they do”

Sense blood calcium and, when it falls, release PTH to draw calcium from bone, conserve it in the kidneys, and boost its absorption from food.

Key idea

Section titled “Key idea”

Small as they are, the parathyroids are indispensable — calcium is essential for nerves, muscle, and clotting, so their fine control of it is vital. See the calcium–phosphate axis.