Types of drugs and their effect on the body

The commonly abused drugs are opioids, cannabinoids, and coca alkaloids. 

Opioids: These drugs bind to specific opioid receptors in our central nervous system and in the gastrointestinal tract. Heroin is commonly called a smack. Chemically, it is diacetylmorphine; which is a white, odorless, bitter crystalline compound. Heroin is obtained by acetylation of morphine. Morphine is extracted from the latex of poppy plant. 

Cannabinoids: These are a group of chemicals which interact with cannabinoid receptors present mainly in the brain. Natural cannabinoids are obtained from the inflorescences of the plant Cannabis sativa. The flower tops, leaves, and resin of this plant are used in various combinations to produce marijuana, hashish, charas, and ganja.