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Module 7: Figure adrenal gland

Adrenal gland structure and function.

The orange-coloured adrenal glands are located on the top of each kidney. A section through the gland illustrates the outer cortex, which is divided into three zones and an inner medulla that has the chromaffin cells. The latter are innervated by the splanchnic nerve. Shown on the right are the functions of the cells specialized to synthesize and secrete hormones (yellow arrows). Angiotensin II and high K+ stimulate aldosterone release (Module 7: Figure glomerulosa cell signalling), corticotropin [or adrenocorticotrophic hormone (ACTH)] stimulates the release of cortisol, while release of acetylcholine (ACh) from the splanchnic nerve endings activates the chromaffin cells to release adrenaline (epinephrine) (Module 7: Figure chromaffin cell secretion).