Epinephrine (INN) (IPA: ) or adrenaline (European Pharmacopoeia and BAN) (IPA: ), sometimes spelled "epinephrin" or "adrenalin" respectively, is a hormone when carried in the blood and a neurotransmitter when it is released across a neuronal synapse. It is a catecholamine, a sympathomimetic monoamine derived from the amino acids phenylalanine and tyrosine. The Latin roots ad-+renes and the Greek roots epi-+nephros both literally mean "on/to the kidney" (referring to the adrenal gland, which sits atop the kidneys and secretes epinephrine). Epinephrine is sometimes shortened to epi or to EP in medical jargon.