The fight-or-flight response, also known as the acute stress response, refers to a physiological reaction that occurs in the presence of something that is terrifying, either mentally or physically.
IMMEDIATE PHYSIOLOGICAL REACTIONS INCLUDE:
Acceleration of heart and lung action
Paling or flushing, or alternating between both
Inhibition of stomach and upper-intestinal action to the point where digestion slows down or stops
General effect on the sphincters of the body
Constriction of blood vessels in many parts of the body
Liberation of metabolic energy sources (particularly fat and glycogen) for muscular action
Dilation of blood vessels for muscles
Inhibition of the lacrimal gland (responsible for tear production) and salivation
Dilation of pupil (mydriasis)
Relaxation of bladder
Inhibition of erection
Loss of hearing
Tunnel vision (loss of peripheral vision)
Disinhibition of spinal reflexes
Tremors
Increased muscle tension in order to provide the body with extra speed and strength.
