Adrenaline is a hormone that is produced in the adrenal medulla, which is in the inner adrenal gland. This gland sits atop the kidney. When put under stress this gland is stimulated by the nervous system and releases adrenaline into the blood stream. The release of adrenaline is a three step process. First, the hypothalamus produces hormones that stimulate the pituitary gland. Next, the pituitary gland then produces corticotropin hormones which are hormones that stimulate the adrenal glands that eventually produce adrenaline.
In 1895, George Oliver and Edward Schäfer discovered that that when the secretions of adrenal glands were extracted and injected into an experimental animal, they could raise blood pressure. The purification of this principle became a matter of interest, and in 1897, John Abel and Albert Crawford thought that they had succeeded when they purified a crystalline principle they named epinephrine. Adrenaline is used for many different purposes. It is used to control hemorrhages in surgery and to treat asthma and other allergies. According to the MSDS, excessive digestion of adrenaline is fatal. It can also be very irritant to eyes and can be absorbed through skin. Adrenaline can also be used to prevent cardiac arrest. Adrenaline can also be found in some nasal sprays to open up nasal passages. This has a short term effect. Adrenaline is helpful to survive in dangerous situations. If you were pinned down by a boulder, adrenaline would kick in and would help you to move the boulder off of you. This process is natural and you can find your way out of unhappy states. When you are put into a dangerous situation like that, your heart rate is elevated and your blood pressure is elevated. Adrenaline redirects blood to large muscle groups so that you are given more strength and stamina to get out of the dangerous situation.