Definition of Carotid body

Carotid body: A small "body" of tissue rich in capillaries, at the spot the carotid artery branches in the neck, containing cells that sense the oxygen and carbon dioxide levels in blood and from which messages are dispatched to the medulla (in the brain) to regulate the heart rate.

Source: MedTerms™ Medical Dictionary
http://www.medterms.com/script/main/art.asp?articlekey=20471
Last Editorial Review: 6/14/2012