Taken https://www.westonaprice.org/health-topics/the-pursuit-of-happiness/?fbclid=IwAR1lC_2Ug3HGgj_8jAIARU49T47VagapzlH5IKshq_IYch9JMOKcUuOLurI#gsc.tab=0 

Photo by Artem Beliaikin on unsplash.com 

Arachidonic acid is the direct precursor to the endocannabinoids, the natural compounds made within the body that activate the cannabinoid receptors. These compounds and their receptors are named after Cannabis sativa, also known as marijuana. The active component of marijuana, THC, activates the same receptors, although since it is a pharmacological agent provided at unnaturally high doses, it has many undesirable effects that the natural activators derived from arachidonic acid do not have. 

A brain cell will only convert arachidonic acid into endocannabinoids in response to a rapid influx of calcium into the cell. This influx is tightly controlled: the cell deliberately keeps the concentration of calcium outside its boundaries ten thousand-fold higher than the concentration of calcium within its boundaries; only when told to do so by another chemical signal will the cell open the calcium channels that will let this mineral come flooding in. Obviously, if calcium is not present, due to deficiency of either calcium or vitamin D, there will be no influx of calcium into the cell to initiate the conversion of arachidonic acid to endocannabinoids. Calcium must therefore be obtained in the diet, and vitamin D is necessary to absorb this vital mineral so that it can be transported through the blood and into the brain. It is also possible that the brain uses vitamin D as the direct chemical signal to open the calcium channels since a number of other cell types use vitamin D in a similar way. 

Endocannabinoids regulate the adrenal response to stress, mediated primarily by the hormone cortisol, which is responsible for the “fight-or-flight” response; they also regulate the production of dopamine in the brain, which is responsible for the motivation to sustain goal-oriented effort over time. By curbing the excess production of cortisol and supporting adequate production of dopamine, endocannabinoids help prevent excess tension, anxiety, burnout, and feelings of self-defeat and help support the confrontation of challenges with the attitudes necessary for success.