What substance is released by the adrenal glands during the fight or flight response?

The substance released by the adrenal glands during the fight or flight response is adrenaline, also known as epinephrine. This hormone plays a crucial role in preparing the body to react to stress or danger. When faced with a threatening situation, the adrenal glands secrete adrenaline into the bloodstream, which leads to a series of physiological changes.

These changes include an increased heart rate, dilated air passages, heightened blood flow to muscles, and a surge of energy. These responses are aimed at enhancing the body's ability to respond quickly, either by fighting or fleeing from the perceived threat.

Cortisol, while also released during stress, primarily helps in long-term stress management rather than the immediate reaction associated with the fight or flight response. Insulin is involved in regulating blood sugar levels, and estrogen is a hormone primarily related to the reproductive system and does not play a direct role in acute stress responses. Thus, adrenaline is the hormone that specifically triggers the immediate physiological reactions associated with the fight or flight response.