The  endocannabinoid system, broadly speaking, includes:
* The endogenous arachidonate-based lipids, anandamide (N-arachidonoylethanolamide) and 2-AG, besides other N-acylethanolamines (NAEs); these are known as "endocannabinoids" and are physiological ligands for the cannabinoid receptors. Endocannabinoids are all eicosanoids.
* The enzymes that synthesize and degrade the endocannabinoids, such as fatty acid amide hydrolase or monoacylglycerol lipase.
* The cannabinoid receptors CB and CB, two G protein-coupled receptors that are located in the central and peripheral nervous systems.
The neurons, neural pathways, and other cells where these molecules, enzymes, and one or both cannabinoid receptor types are all colocalized collectively comprise the endocannabinoid system.
The endocannabinoid system has been studied using genetic and pharmacological methods. These studies have revealed that cannabinoids act as neuromodulators for a variety of processes, including motor learning, appetite, and pain sensation, among other cognitive and physical processes.  The localization of the CB1 receptor in the endocannabinoid system has a very large degree of overlap with the orexinergic projection system, which mediates many of the same functions, both physical and cognitive.  Moreover, CB1 is colocalized on orexin projection neurons in the lateral hypothalamus and many output structures of the orexin system, where the CB1 and orexin receptor 1 (OX1) receptors physically and functionally join to form the CB1–OX1 receptor heterodimer.