Which hormone stimulates the fight-or-flight response?

The hormone that stimulates the fight-or-flight response is adrenaline, which is also known as epinephrine. Adrenaline is produced by the adrenal glands and is released into the bloodstream during stressful situations. When adrenaline is released, it triggers a series of physiological changes that prepare the body to either confront or flee from a perceived threat. These changes include increased heart rate, elevated blood pressure, heightened energy availability through the breakdown of glycogen to glucose, and expanded air passages to improve breathing.

This response is crucial for survival, allowing an individual to react quickly to danger. The activation of the fight-or-flight response via adrenaline is a key component of the body's stress response system and is essential in situations that demand immediate physical action.