adrenaline
Meaning of adrenaline: Adrenaline is a hormone and neurotransmitter released during stress that rapidly raises heart rate, blood pressure, and alertness.
Definition of adrenaline
Adrenaline is a substance that acts both as a hormone, traveling through the bloodstream to affect distant tissues, and as a neurotransmitter, carrying signals between nerve cells. It is produced mainly by the adrenal medulla, the inner portion of the adrenal glands sitting atop each kidney, and is released rapidly in response to a perceived threat, physical exertion, or other acute stress.
Once released, adrenaline increases heart rate and the force of each heartbeat, raises blood pressure, widens the airways to ease breathing, and redirects blood flow toward muscles, changes collectively known as the fight or flight response. It also triggers release of stored glucose to provide readily available energy.
Adrenaline is also manufactured as a medication, given by injection to treat severe allergic reactions and certain life threatening heart rhythm problems, since its rapid, powerful effects on the heart and blood vessels can help reverse a dangerous drop in blood pressure or airway swelling.
Also known as
Used in a sentence
Adrenaline was administered by injection to treat the patient's severe allergic reaction.
Good to know
Adrenaline and epinephrine are the same substance under two different names, epinephrine being the term generally preferred in the United States and adrenaline more common elsewhere, though both appear throughout medical literature.
Word origin
Where “adrenaline” comes from
Formed from Latin ad-, meaning near or toward, and ren, meaning kidney, since adrenaline is produced by the adrenal glands positioned near the kidneys.