(a) : Adrenaline (epinephrine), also called emergency hormone, is a hormone, produced by the medulla of the adrenal glands, that increases heart activity, improves the power and prolongs the action of muscles, and increases the rate and depth of breathing to prepare the body for ‘fright, flight, or fight’. At the same time it inhibits digestion and excretion. Similar effects are produced by stimulation of the sympathetic nervous system.