Adrenaline, also known as epinephrine, is a hormone and medication which is involved in regulating visceral functions. Adrenaline is normally produced both by the adrenal glands and by a small number of neurons in the medulla oblongata. It plays an important role in the fight-or-flight response by increasing blood flow to muscles, output of the heart by acting on SA Node, pupil dilation response and blood sugar level. It does this by binding to alpha and beta receptors. It is found in many animals and some single-celled organisms. Polish physiologist Napoleon Cybulski first isolated adrenaline in 1895.
