fight-or-flight reaction

[ fahyt-awr-flahyt ]

noun

, Physiology, Psychology.

1. the response of the sympathetic nervous system to a stressful event, preparing the body to fight or flee, associated with the adrenal secretion of epinephrine and characterized by increased heart rate, increased blood flow to the brain and muscles, raised sugar levels, sweaty palms and soles, dilated pupils, and erect hairs.

fight or flight reaction

1. The set of processes that occur in the body when it is confronted with some form of physical or mental stress . For example, if a person is faced with danger (as from a vicious animal about to attack), the nervous system signals for adrenaline and other hormones to be released into the blood . These hormones prepare the body either to confront the attacking animal or to flee to safety (thus, “fight or flight”). Changes in the body include increased heart rate, dilated pupils of the eye (to improve vision), and increased supply of blood to the muscles (to prepare the body for action).

Example Sentences

Mostly water, nutrients, and red blood cells, what runs through our veins also transports a huge variety of signaling molecules that coordinate metabolism, immune responses, fight-or-flight reactions, and myriad other activities.

From Popular-Science