When it comes to producing that sweet, psychoactive THC then you must look no further than those fine crystals on your cannabis plants; trichomes! 
Trichomes are the tiny little white hairs you will find all over your cannabis plants - on the buds, stems, roots, and leaves they are very small but in large quantities are easily noticeable. Trichomes store the THC and CBD - you will be able to notice which ones store this as they will be significantly bigger and more bulbous and will be found on the buds of your cannabis plants. Trichomes at the root of the cannabis plants are used to absorb nutrients, minerals, and water and they are very small, microscopic trichomes.
The endocannabinoid system manages and controls some of the human body's key biological functions such as mood, fertility, pain, memory and appetite, the last one being something all smokers should know all about. When humans ingest cannabinoids, they act somewhat like keys, unlocking the body's receptors and allowing for certain elements of perception and feeling to be altered. THC and CBD are perhaps the two most famous cannabinoids, they are compounds found in cannabis.