What is the endocannabinoid system?

"The endocannabinoid system (ECS) is a group of naturally-occurring molecules (endocannabinoids) and their receptors in the brain and elsewhere throughout the nervous system. The endocannabinoid system is comprised of two main types of cannabinoid receptors, CB1 and CB2.[1]

These CB1 and CB2 receptors respond to both endocannabinoids (produced by the body: anandamide) and phytocannabinoids (produced by the cannabis plant: THC, CBD). CB1 receptors are found primarily in the brain, while CB2 receptors are more densely populated throughout the immune system, gastrointestinal system, and portions of the nervous system.[2]

CB1 receptors and CB2 receptors both respond differently to the variety of phytocannabinoids from the cannabis plant. In the past two decades, increased cannabis research has suggested that the endocannabinoid system plays a major role in regulating psychological and physiological health and disease."[3]

[1] - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219532/

[2] - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2697681/

[3] - http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3481523/