Endocrine System > Adrenal Glands

Histology of the Adrenal Gland

"Two glands in one" is an apt description of the adrenal gland. Sectioning through this endocrine gland reveals a pale medulla surrounded by a darker cortex, and each of these two regions produces a distinctly different group of hormones. Prior to embarking on the lessons below, it would be best to review the core section Functional Anatomy of the Adrenal Gland.

Summary of LessonLink
The most distinctive feature of the mammalian adrenal viewed at low magnification is its partitioning into cortex versus medulla. Both tissues are very richly vascularized.
The adrenal cortex is partitioned into three concentric zones of steroid-synthesizing cells - glomerulosa, fasiculata and reticularis. Although the boundaries between these zones are somewhat indistinct, each has a characteristic arrangement of cells.
The medulla is populated with large columnar cells called chromaffin cells, which synthesize and secrete catecholamines. Ganglion cells are also observed, but infrequently. Blood from throughout the adrenal gland collects into large medullary veins to exit the gland.

Adrenal Glands: Introduction and Index

Send comments to Richard.Bowen@colostate.edu