fight or fly

the eye (receptor) will generate nerve impulses that will be carried by the afferent neurone to the brain. From the brain, nerve impulses will be transmitted through the efferent neurone to the adrenal gland, which will secrete adrenaline hormone.This hormone is secreted directly into bloodstream and is carried by blood to a few target organs. The adrenaline is carried to heart muscle to increase the heartbeat rate. It's also transported to the lungs to increase the breathing rate. It also stimulates the conversion of glycogen to glucose for muscle contraction (increase metabolic rate). Adrenaline also reacts on the skin causing vasodilation.