Adrenal medulla

Part of the adrenal gland involved in the production of catecholamines

Adrenal medulla

The adrenal medulla is the inner part of the adrenal gland, which is located on top of each kidney. It plays a crucial role in the body's response to stress by producing catecholamines, primarily epinephrine (adrenaline) and norepinephrine (noradrenaline).

Structure

The adrenal medulla is surrounded by the adrenal cortex, which is the outer layer of the adrenal gland. The medulla itself is composed of chromaffin cells, which are derived from neural crest cells during embryonic development. These cells are responsible for the synthesis and secretion of catecholamines.

Function

The primary function of the adrenal medulla is to secrete catecholamines in response to stress. When the body perceives a stressful situation, the sympathetic nervous system stimulates the adrenal medulla to release epinephrine and norepinephrine into the bloodstream. These hormones prepare the body for a "fight-or-flight" response by increasing heart rate, blood pressure, and blood glucose levels, among other physiological changes.

Hormones

The main hormones produced by the adrenal medulla are:

• Epinephrine (Adrenaline): Increases heart rate, dilates air passages, and participates in the "fight-or-flight" response.
• Norepinephrine (Noradrenaline): Works alongside epinephrine to increase heart rate and blood pressure, and also acts as a neurotransmitter in the central nervous system.

Clinical significance

Disorders of the adrenal medulla can lead to various medical conditions. One such condition is pheochromocytoma, a rare tumor of the chromaffin cells that can cause excessive production of catecholamines, leading to hypertension and other symptoms. Diagnosis and management of such conditions require careful medical evaluation and treatment.

Related pages

• Adrenal gland
• Adrenal cortex
• Sympathetic nervous system
• Pheochromocytoma

Gallery

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  Diagram of the adrenal gland

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  Histological section of the adrenal medulla