Zona fasciculata
Layers of cortex.
Gray's	subject #277 1278

The zona fasciculata constitutes the middle zone of the adrenal cortex, sitting directly beneath the zona glomerulosa. Constituent cells are organized into bundles or "fascicles".

The zona fasciculata chiefly produces glucocorticoids (mainly cortisol in the human), which regulates the metabolism of glucose, especially in times of stress (e.g., part of the fight-or-flight response). This tissue also generates a small amount of weak androgens (e.g., dehydroepiandrosterone). In certain animals such as rodents, the lack of 17alpha-hydroxylase results in the synthesis of corticosterone instead of cortisol.

Steroid-producing adrenal tumours and hyperplasias of the zona fasciculata result in excess cortisol production and are the cause for adrenal Cushing's syndrome. The genetic disorder McCune-Albright syndrome can also present Cushing's syndrome in affected patients.

adrenal gland (zona fasciculata layer).

[edit] External links

• Histology at BU 14502loa
• Anatomy Atlases - Microscopic Anatomy, plate 15.292 - "Adrenal Gland"