BY VIOLA BRUGNATELLI · PUBLISHED MAY 5, 2015 · UPDATED OCTOBER 23, 2017 Highlights: The endocannabinoid system is the most important physiologic system involved in establishing and maintaining human health Sea squirts, tiny nematodes, and all vertebrate species share the endocannabinoid system as an essential part of life and adaptation to environmental changes Currently, there are two recognised cannabinoid receptors: CB1, predominantly present in the nervous system, connective tissues, gonads, glands, and organs; and CB2,