nadledvin

Nadledviny, known in English as the adrenal glands, are a paired set of small endocrine glands located at the superior poles of the kidneys. They are composed of an outer cortex and an inner medulla, with distinct embryonic origins and hormone roles.

Anatomy and location: They lie in the retroperitoneum, enclosed by perirenal fat and renal fascia. The right gland sits posterior to the liver, while the left lies near the spleen and stomach.

Structure and hormones: The cortex contains three zones that produce mineralocorticoids (aldosterone), glucocorticoids (cortisol), and adrenal androgens. The medulla derives from neural crest cells and secretes catecholamines (epinephrine and norepinephrine) in response to sympathetic signals.

Physiology: Aldosterone regulates sodium and potassium balance and blood pressure; cortisol modulates metabolism, stress response, and inflammation; catecholamines prepare the body for acute stress through rapid cardiovascular and metabolic effects.

Vascularization and innervation: The glands receive arterial supply from the superior, middle, and inferior suprarenal arteries. Venous drainage is typically into the inferior vena cava (right) or renal vein (left). Sympathetic innervation from preganglionic fibers modulates activity.

Development and clinical relevance: Cortex originates from mesoderm; medulla from neural crest. Disorders include Addison disease (adrenal insufficiency), Cushing syndrome (cortisol excess), congenital adrenal hyperplasia, and pheochromocytoma; incidental adrenal tumors are often discovered on imaging.