suprarenala

The suprarenal glands, commonly known as the adrenal glands, are a pair of small endocrine organs located on the superior poles of the kidneys. They play a central role in the body’s response to stress, metabolism, fluid and electrolyte balance, and blood pressure regulation. The gland is structurally divided into two distinct parts with separate origins and functions: the cortex (outer portion) and the medulla (inner portion).

The adrenal cortex develops from mesoderm and comprises three layers, each producing different hormones. The zona glomerulosa secretes mineralocorticoids, primarily aldosterone, which helps regulate sodium and potassium balance and thus blood pressure. The zona fasciculata produces glucocorticoids, mainly cortisol, which influence metabolism, immune response, and stress adaptation. The zona reticularis synthesizes androgens, providing precursors for sex hormones. The adrenal medulla derives from neural crest cells and releases catecholamines, chiefly epinephrine and norepinephrine, in response to sympathetic stimulation, supporting the fight-or-flight response.

Hormone regulation involves the hypothalamic-pituitary-adrenal axis. The hypothalamus releases corticotropin-releasing hormone, stimulating the pituitary to secrete adrenocorticotropic hormone, which in turn prompts the cortex to produce corticosteroids. Cortisol provides negative feedback to the hypothalamus and pituitary to modulate its own production.

Clinically, dysfunctions of the suprarenal glands include Addison’s disease (adrenal insufficiency), Cushing’s syndrome (excess cortisol), primary hyperaldosteronism, and pheochromocytoma (a catecholamine-secreting tumor). Understanding adrenal structure and function is essential for diagnosing hormonal disorders and managing systemic stress responses.