Alila Academy

The adrenal glands are a pair of glands sitting on top of the kidneys. Each gland consists of an outer cortex of glandular tissue, and an inner medulla of nervous tissue.

The adrenal cortex produces a variety of steroid hormones, all of which are based on cholesterol. The cortex has three layers: zona glomerulosa, zona fasciculata, and zona reticularis. Each layer secretes its own set of hormones.

- The outermost layer, zona glomerulosa, produces mineralocorticoids, so named for their role in regulating minerals, in particular sodium and potassium. These hormones primarily act on the kidneys to control fluid and electrolyte balance. 

The major mineralocorticoid is aldosterone. Aldosterone increases potassium excretion, as well as sodium and water retention by the kidneys, thereby increasing blood volume and blood pressure. 

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