You are likely aware of the 11 major organ systems in the human body: circulatory, respiratory, urinary, reproductive, integumentary, skeletal, muscular, nervous, endocrine, lymphatic and digestive systems. Combined, these systems do everything from circulating blood and filtering oxygen, to allowing you to lift weights and run on the treadmill.
However, there is also the endocannabinoid system (ECS). While it is less well-known than the other major organ systems in the body, the ECS is deeply involved in establishing and maintaining human health in various ways.