Which part of poppy plant is used to obtain the drug "smack"?

Latex poppy plant is used to obtain the drug "smack".  Opioids are the drugs, which bind to specific opioid receptors present in our central nervous system and gastrointestinal tract. Heroin, commonly called smack is chemically diacetylmorphine, which is a white, odourless, bitter crystalline compound. This is obtained by acetylation of morphine, which is extracted from the latex of poppy plant Papaver somniferum. Generally taken by snorting and injection, heroin is a depressant and slows down body functions.