Light micrograph section of an adult parathyroid gland. Cell cord formed exclusively by chief cells. The chief cells of the parathyroid are small cells (in fact, one of the smallest cell types in the body). These cells are the only ones present in the gland in the first years of life. Among the cell cords are narrow connective tissue septa occupied almost entirely by vessels, very abundant, as is characteristic of the entire endocrine system. On the outside, there are ample conjunctive septa, with thicker vessels and adipocytes, another characteristic of this gland.