Tobacco

Tobacco
Tobacco History
Tobacco Cultivation
Tobacco Types
Tobacco Products

Tobacco (Nicotiana spp., L.) refers to a genus of broad-leafed plants of the nightshade family indigenous to North and South America, or to the dried and cured leaves of such plants. Tobacco leaves are often smoked in the form of a cigar or cigarette, or in a smoking pipe, or in a water pipe or a hookah. Tobacco is also chewed, "dipped" (placed between the cheek and gum), and sniffed into the nose as finely powdered snuff. The Spanish word "tabaco" is thought to have its origin in Arawakan language, particularly, in the Taino language of the Caribbean, said to refer to a roll of these leaves (according to Bartolome de Las Casas, 1552) or to the "tabago", a kind of y-shaped pipe for sniffing tobacco smoke (according to Oviedo), but Sp. tabaco (also It. tobacco) was commonly used to define medicinal herbs from 1410, originating from the Arabic "tabbaq", reportedly since the 9th century, as the name of various herbs. The word might then be European, and later applied to this plant from the Americas.

Tobacco contains the alkaloid nicotine, a powerful neurotoxin that is particularly harmful to insects. All means of consuming tobacco result in the absorption of nicotine in varying amounts into the user's bloodstream, and over time the development of tolerance and dependence. Absorption quantity, frequency and speed seem to have a direct relationship with how strong a dependence and tolerance, if any, might be created. A lethal dose of nicotine is contained in as little as one half of a cigar or three cigarettes; however, only a fraction of the nicotine contained in these products is actually released into the smoke, and most clinically significant cases of nicotine poisoning are the result of concentrated forms of the compound used as insecticides. Other active alkaloids in tobacco include harmala.
Major hazards of tobacco use, however, involve carcinogenic compounds in tobacco and tobacco smoke. Many jurisdictions have enacted smoking bans in an effort to minimize possible damage to public health caused by tobacco smoking.

source: wikipedia
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