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How do the adrenal glands contribute to the fight-or-flight response?
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Endocrine system
The glands of the human endocrine system.
The adrenal glands play a critical role in the fight-or-flight response through the coordinated activity of their two distinct anatomical regions: the adrenal medulla and the adrenal cortex.12
- Adrenal Medulla: Upon activation of the sympathetic nervous system, the adrenal medulla secretes large quantities of catecholamines—specifically epinephrine and norepinephrine—into the bloodstream. These hormones initiate rapid physiological changes, such as increased heart rate, bronchial dilation, and the breakdown of liver glycogen to boost blood glucose levels, preparing the body to react to an acute threat.134
- Adrenal Cortex: In concert with the medulla, the adrenal cortex increases the secretion of cortisol. This hormonal response helps the body manage stress by influencing metabolism and maintaining physiological stability during the encounter.1324
Together, these secretions ensure the body is physically and metabolically primed to either confront or retreat from immediate danger.13