Binjurebarken

Binjurebarken, or the adrenal cortex, is the outer portion of the adrenal gland, located on the superior aspect of each kidney. It is derived from the mesoderm and comprises three distinct cortical zones: zona glomerulosa, zona fasciculata, and zona reticularis, each producing specific steroids.

The zona glomerulosa synthesizes mineralocorticoids, chiefly aldosterone, which regulate electrolyte balance and blood pressure through the renin–angiotensin system. The zona fasciculata produces glucocorticoids, mainly cortisol, involved in glucose metabolism, immune regulation, and the stress response; secretion is primarily controlled by adrenocorticotropic hormone (ACTH) from the pituitary, with a circadian rhythm. The zona reticularis secretes androgens, such as dehydroepiandrosterone (DHEA), also under ACTH control.

The adrenal cortex receives arterial blood from several suprarenal arteries and drains via adrenal veins; innervation is sympathetic. Hormone release is regulated by pituitary signals and, for aldosterone, by the renin–angiotensin system. Cortisol exerts negative feedback on ACTH production.

Developmentally, the cortex forms from mesodermal tissue of the developing adrenal primordium. Clinically, dysfunction can lead to primary adrenal insufficiency (Addison’s disease), Cushing’s syndrome from cortisol excess, or congenital adrenal hyperplasia due to enzymatic defects (most often 21-hydroxylase deficiency). Adrenal cortical tumors can alter hormone production and are evaluated with imaging and biochemical testing.