Name the plant source of the drug popularly called "smack". How does it affect the body of the abuser?

Explanation

Heroin (Commonly called smack) or diacetyl morphine is an opiate narcotic and derived from the opium of white poppy plant (Papaver somniferum). It is a powerful analgestic but causes addiction so has been banned for medicinal use. When heroin is injected intravenously, it produces the rapid response called rush. Its continuous use causes bradycardia, hypotension, constricted pupils, delayed responses, etc.