SMOKING -

1. It means to draw tobacco smoke into the mouth or lungs & exhale it via mouth, nostrils or both.
2. Tobacco is obtained from Nicotiana tobacum & Nicotiana rustica of solanaceae family, name was given after Jean Nicot.
3. Tobacco is used for smoking, chewing & snuffing.
4. It's main toxic component is nicotine.
5. Other harmful components are CO, benzpyrene and tar.
6. Tar contains ammonia, formaledehyde aceteldehyde, HCN, NO₂, NO₃ & acrolein.
7. Nicotine stimulates conduction of nerve impulses, causes alertness, relaxes muscles, increases heart beat & B.P., retard foetal growth.