Adrenal Gland Histology

Abstract

The adrenal glands are composed of two distinct types of tissue: adrenal cortical tissue and adrenal medullary tissue. The adrenal cortex is approximately 2 mm thick and surrounds the adrenal medulla. The adrenal cortex shows zonation with the thin discontinuous zona glomerulosa most peripherally, the zona fasciculata comprising most of the cortex, and the innermost zona reticularis cells, which are adjacent to the adrenal medulla. The adrenal cortex synthesizes mineralcorticoids, glucocorticoids, and sex steroids. These steroids have been associated with different zones of the adrenal cortex, with aldosterone produced by the zona glomerulosa, cortisol produced by the zona fasciculata and somewhat by the zona reticularis, and dehydroepiandrosterone sulfate synthesized by the zona reticularis and somewhat by the zona fasciculata. This simplified characterization is proving more complex as more is learned about the adrenal cortex.