A short term stress response is controlled by adrenaline (epinephrine) and noradrenaline (norepinephrine). When an organism interacts with a stressful situation, these two hormones are released by the adrenal medulla into the blood flow. These hormones bind specific adrenal receptors located on the surface of the cells of various organs and tissues. Activation of the receptors stimulates particular signaling pathways in the cells, changing their metabolism. As a result, adrenaline and noradrenaline stimulate glycogen breakdown in the liver and skeletal muscles, increasing blood glucose level. They increase heart rate, dilate bronchioles, and increase blood pressure. All these processes enhance blood oxygenation and increase blood flow to the brain, muscles, and heart provide an urgent response to a stress factor.