Structure of the Adrenal Medulla

The adrenal medulla is the inner part of the adrenal gland and is made up of clusters of cells called chromaffin cells. These cells are derived from the neural crest and are closely associated with the sympathetic nervous system.

Hormones Produced

The adrenal medulla primarily produces two hormones: epinephrine (also known as adrenaline) and norepinephrine (noradrenaline). These hormones are released into the bloodstream in response to signals from the sympathetic nervous system.

Function

When the body perceives a threat or stress, the sympathetic nervous system signals the adrenal medulla to release epinephrine and norepinephrine. These hormones act on various organs to initiate the "fight or flight" response. They can increase heart rate, dilate airways, and redirect blood flow to the muscles, preparing the body to respond to the perceived threat.

Regulation

The release of hormones from the adrenal medulla is regulated by the sympathetic nervous system, which responds to signals from the brain in times of stress or danger.