adrenal medulla

anatomy

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July 23, 2026

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The adrenal medulla is the inner part of the adrenal gland. It is composed of chromaffin tissue, which contains cells that produce and secrete catecholamines, primarily epinephrine and norepinephrine.1

These hormones are released in response to stress and are a key part of the fight-or-flight response. They increase heart rate, blood pressure, and blood sugar levels, preparing the body for immediate action. Norepinephrine also functions as a neurotransmitter in the sympathetic nervous system.21

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human nervous system
The endocrine system
The adrenal medulla, on the other hand, is innervated by sympathetic preganglionic neurons. Within the adrenal medulla are chromaffin cells, which are homologous to sympathetic neurons and, like sympathetic neurons, are developed from embryonic neural crest cells. Chromaffin cells produce epinephrine (adrenaline) and, to a much…
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The adrenal medulla, on the other hand, is innervated by sympathetic preganglionic neurons. Within the adrenal medulla are chromaffin cells, which are homologous to sympathetic neurons and, like sympathetic neurons, are developed from embryonic neural crest cells. Chromaffin cells produce epinephrine (adrenaline) and, to a much…
Read More