Adrenaline

Adrenaline is a hormone produced by the adrenal glands during high stress or exciting situations. This powerful hormone is part of the human body's acute stress response system, also called the "fight or flight" response. It works by stimulating the heart rate, contracting blood vessels, and dilating air passages, all of which work to increase blood flow to the muscles and oxygen to the lungs. Additionally, it is used as a medical treatment for some potentially life-threatening conditions including anaphylactic shock. In the US, the medical community largely refers to this hormone as epinephrine, although the two terms may be used interchangeably.

The Adrenal Glands

The adrenal glands are found directly above the kidneys in the human body, and are roughly 3 inches (7.62 cm) in length. Adrenaline is one of several hormones produced by these glands. Along with norepinephrine and dopamine, it is a catecholamine, which is a group of hormones released in response to stress. These three hormones react with various body tissues, preparing the body to react physically to the stress causing situation.