Module 7: Figure parathyroid gland
Location and structure of parathyroid glands.
In humans, there are four separate parathyroid glands, which are closely associated with the thyroid gland. The main cell type in the parathyroid gland is the chief cells that are arranged into sheets that lie close to blood vessels. High levels of Ca2+ acts through a Ca2+-sensing receptor (CaR) to inhibit the release of parathyroid hormone (PTH).