Zona glomerulosa

The zona glomerulosa of the adrenal gland is the most superficial layer of the adrenal cortex, lying directly beneath the adrenal gland's capsule. Its cells are ovoid in shape and are arranged in clusters or arches (glomus is Latin for "ball").

In response to increased potassium levels or decreased blood flow to the kidneys, cells of the zona glomerulosa secrete the mineralocorticoid aldosterone into the blood as part of the renin-angiotensin system. Aldosterone regulates the body's concentration of electrolytes, primarily sodium and potassium, by acting on the distal convoluted tubule of kidney nephrons to:
 * increase sodium reabsorption
 * increase potassium excretion
 * increase water reabsorption through osmosis

The enzyme aldosterone synthase acts in this location.