Fight-or-flight reactions cause activation of

Fight or flight reaction is a physiological reaction that occurs in response to emergency. Emergency hormones is secreted by adrenal medulla of adrenal gland. Adrenal medulla secretes epinephrine and nor-epinegphrine commonly called catecholamines hormones which stimulates sweating, heartbeat and breathing rate.
These hormones also causes dilation of coronary artery (supplying blood to heart muscles) a bronchioles (for increasing inspiratory volume) and pupil (for better vision)