Zona glomerulosa

Zona glomerulosa
Layers of cortex.
Details
Latin	Zona glomerulosa
Dorlands /Elsevier	z_01/12869730
Anatomical terminology []

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

In response to increased potassium levels, renin or decreased blood flow to the kidneys, cells of the zona glomerulosa produce and secrete the mineralocorticoid aldosterone into the blood as part of the renin-angiotensin system. Although sustained production of aldosterone requires persistent calcium entry through low-voltage activated Ca²⁺ channels, isolated zona glomerulosa cells are considered nonexcitable, with recorded membrane voltages that are too hyperpolarized to permit Ca²⁺ channels entry. However, mouse zona glomerulosa cells within adrenal slices spontaneously generate membrane potential oscillations of low periodicity; this innate electrical excitability of zona glomerulosa cells provides a platform for the production of a recurrent Ca²⁺ channels signal that can be controlled by angiotensin II and extracellular potassium, the 2 major regulators of aldosterone production. 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.