The adrenal or suprarenal glands are endocrine organs anatomically associated with the superior poles of both kidneys. The right gland is pyramid-shaped, while the left gland is more semilunar in shape and larger than the right.

Each gland consists of an outer adrenal cortex and an inner adrenal medulla.

The adrenal glands are related to other abdominal structures. Along the anterior side of the right adrenal gland passes a part of the right lobe of the liver and the inferior vena cava, while anterior to the left adrenal gland lies part of the stomach, pancreas, and, occasionally, the spleen. Posterior to both glands is the diaphragm.

Both adrenal glands are covered by the perinephric fat and enclosed in the renal fascia with a thin septum separating each adrenal gland from its associated kidney.

The adrenal glands synthesize and release various hormones in the bloodstream, which are included in regulation of metabolism, blood pressure, electrolyte balance, stress, and other important body functions. The adrenal cortex is the production site for steroid hormones - mineralocorticoids (such as aldosterone), glucocorticoids (cortisol, cortisone), and androgens (DHEA, androstenedione), while the adrenal medulla mainly produces the catecholamines (adrenaline and noradrenaline).

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Adrenal glands