The four small parathyroid glands are located in the neck, right next to the thyroid gland. The parathyroid glands are endocrine organs producing a hormone called parathormone (PTH) and are involved in calcium blood level regulation.
In the low power magnification a round, encapsulated organ is seen. Within the gland there is a lot of adipose tissue and numerous venules, which run through the gland that are filled with red blood cells. These are seen either in cross section or longitudinal section.
The parathyroid gland has two cell types, chief cells and oxyphil cells. Chief cells are more numerous and have a round nucleus surrounded by a small amount of cytoplasm. Chief cells produce PTH. The oxyphil cells are seen in scattered groups among the chief cells. They have a slightly smaller nucleus and eosinophilic cytoplasm. The function of the oxyphil cells is unknown.