出国留学网专题频道尼古丁栏目，提供与尼古丁相关的所有资讯，希望我们所做的能让您感到满意！ 烟碱（Nicotine），俗名尼古丁，是一种存在于茄科植物（茄属）中的生物碱，也是烟草的重要成分，还是N胆碱受体激动药的代表，对N1和N2受体及中枢神经系统均有作用，无临床应用价值。尼古丁会使人上瘾或产生依赖性（最难戒除的毒瘾之一），人们通常难以克制自己，重复使用尼古丁也增加心脏速度和升高血压并降低食欲。大剂量的尼古丁会引起呕吐以及恶心，严重时人会死亡。烟草中通常会含有尼古丁，这使许多吸烟者无法戒掉烟瘾。
12月23日 出国留学网liuxue86.com英语频道特为大家准备相关的学习资料，希望对大家有用。
The Thinking Man's Choice
Contact is made. Nerves order the heart to pump faster. Adrenalin surges to action. Nerves constrict the blood vessels in the extremities of the body. Skin temperature drops. Fingers and toes grow colder. Blood pressure jump. An alcoholic or a dope addict in the first stages of a "cure"? A man being catapulted into outer space? No! These effects stem from smoking just one cigarette.
The United States Public Health Service is issuing continual warnings to smokers. If they abstain completely from smoking, their chances of acquiring lung cancer will be one in 275. Their chances of dying of lung cancer will be one in 10 if they become heavy smokers─two or more packs a day. Lung cancer is fatal in 95 per cent of all cases.
But in spite of glaring evidence and frequent warnings, the public is smoking more and more. The Department of Agriculture estimates that this year's consumption of cigarettes will reach 180 packs per person fifteen years of age and over. How many cigarettes does this mean per person?─3600.
Why is smoking such an important problem? Because smoking is not a mere habit, as so many think it is. No, it is more serious than that. A habit can be broken easily enough, but an addiction cannot. Smokers lapse into helplessness! Daniel Schubert, of the University of Chicago, quizzed 226 students at a large Northwestern college about their smoking habits─why th...
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