When we hear whistle, we conceive it through sensory neurons of ear that carry it to brain. Brain processes it and interneurons make a link with motorneuron. We run then. Pituatiry gland of brain secretes such hormones that stimulate other endocrine glands. Adrenal medulla of adrenal gland secretes epinephrine or adrenaline hormone that causes to increase blood flow in limbs and decrease in intestines. Heart beat also increase, rapid velocity of blood causes shorten of time for carry of O2 or oxygen from lung to compete this deficiency, rate of breathing is increased. Temperature of our body is rises. Rise in temperature causes sweat glands to sweat. Evaporation of sweat coolens the body. When we stop running, mechanism of feedback happens that return our body mechanism to normal.