The ''zona fasciculata'' (sometimes, fascicular or fasciculate zone) constitutes the middle and also the widest zone of the

adrenal cortex The adrenal cortex is the outer region and also the largest part of an adrenal gland. It is divided into three separate zones: zona glomerulosa, zona fasciculata and zona reticularis. Each zone is responsible for producing specific hormones. It is ...

, sitting directly beneath the ''

zona glomerulosa The ''zona glomerulosa'' (sometimes, glomerular zone) of the adrenal gland is the most superficial layer of the adrenal cortex, lying directly beneath the renal capsule. Its cells are ovoid and arranged in clusters or arches (''glomus'' is Latin ...

''. Constituent cells are organized into bundles or "fascicles". The ''zona fasciculata'' chiefly produces glucocorticoids (mainly

cortisol Cortisol is a steroid hormone, in the glucocorticoid class of hormones. When used as a medication, it is known as hydrocortisone. It is produced in many animals, mainly by the '' zona fasciculata'' of the adrenal cortex in the adrenal g ...

in humans), which regulate the metabolism of glucose. Glucocorticoid production is stimulated by adrenocorticotropic hormone (ACTH), which is released from the

anterior pituitary A major organ of the endocrine system, the anterior pituitary (also called the adenohypophysis or pars anterior) is the glandular, anterior lobe that together with the posterior lobe (posterior pituitary, or the neurohypophysis) makes up the pi ...

, especially in times of stress as part of the

fight-or-flight response The fight-or-flight or the fight-flight-or-freeze response (also called hyperarousal or the acute stress response) is a physiological reaction that occurs in response to a perceived harmful event, attack, or threat to survival. It was first des ...

. The ''zona fasciculata'' also generates a small amount of weak androgens (e.g., dehydroepiandrosterone). The main source of androgens will come from the ''

zona reticularis The zona reticularis (sometimes, reticulate zone) is the innermost layer of the adrenal cortex, lying deep to the zona fasciculata and superficial to the adrenal medulla. The cells are arranged cords that project in different directions giving a n ...

'' region. In certain animals such as

rodents Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

, the lack of 17alpha-hydroxylase results in the synthesis of

corticosterone Corticosterone, also known as 17-deoxycortisol and 11β,21-dihydroxyprogesterone, is a 21-carbon steroid hormone of the corticosteroid type produced in the cortex of the adrenal glands. It is of minor importance in humans, except in the very rar ...

instead of cortisol. Steroid-producing adrenal tumours and

hyperplasia Hyperplasia (from ancient Greek ὑπέρ ''huper'' 'over' + πλάσις ''plasis'' 'formation'), or hypergenesis, is an enlargement of an organ or tissue caused by an increase in the amount of organic tissue that results from cell proliferatio ...

of the ''zona fasciculata'' result in excess cortisol production and are the cause for adrenal Cushing's syndrome. The

genetic disorder A genetic disorder is a health problem caused by one or more abnormalities in the genome. It can be caused by a mutation in a single gene (monogenic) or multiple genes (polygenic) or by a chromosomal abnormality. Although polygenic disorders ...

McCune-Albright syndrome can also present as Cushing's syndrome in affected patients. Adrenal gland (zona fasiculata)

External links

* * - "Adrenal Gland" {{Adrenal gland Adrenal gland it:Zona fascicolata

See also

External links