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The adrenal cortex is organized into zona glomerulosa, zona fasciculata, and zona reticularis, which produce aldosterone, cortisol, and androgens, respectively. Their secretion is regulated differently: aldosterone responds to the renin–angiotensin–aldosterone system, while cortisol and adrenal androgens are ACTH-regulated. Cortisol supports gluconeogenesis, vascular tone, and suppression of immune and inflammatory responses; prolonged excess can impair bone formation. Aldosterone promotes renal sodium reabsorption and potassium and hydrogen ion excretion, helping maintain blood pressure and fluid balance. Adrenal androgens have a smaller role in males and contribute to libido and characteristic hair growth in females. The inner medulla releases epinephrine and norepinephrine in response to sympathetic stimulation.