Adrenalin, also called epinephrine, is a hormone secreted both by the central nervous system where it acts as a neurotransmitter, and by the adrenal glands normally in times of stress
. It belongs to the class of catecholamines. It sets off a series of immediate physiological responses: acceleration of heart rate, increase of the force of heartbeats, rise in blood pressure, dilation of the bronchial tubes... Its role as neurotransmitter allows it to pass on information from one nerve cell to another. Adrenalin is also used in certain serious illnesses like cardiac arrest or anaphylactic shock
(a serious allergic reaction).