

                                
                                  SMOKING
                                

                                    *-

           My Science fair Topic Is "How Much Nicotine There Is After

     Smokes a Single Cigarette". I decided to do that topic so people who

     smoke or think of smoking in the future will realize how dangerous

     smoking is.

                                -NICOTINE-

     Nicotine is an extremely poisonous, colorless, oily liquid

     alkaloid that turns brown on exposure to air. The most potent

     ingredient of the TOBACCO plant, Nicotiniana tabacum, it is

     found mainly in the leaves. Both nicotine and the tobacco plant

     are named for Jean Nicot, a French ambassador who sent tobacco

     from Portugal to Paris in 1560. Nicotine can affect the human

     nervous system, causing respiratory failure and general

     paralysis. It may be absorbed through the skin. Only two or

     three drops (less than 50 mg) of the pure alkaloid placed on

     the tongue is rapidly fatal to an adult. A typical cigarette

     contains 15 to 20 mg of nicotine. However, the actual amount

     that reaches the bloodstream and hence the brain through normal

     SMOKING is only about 1 mg. Nicotine is believed to be

     responsible for most of the short-term and many of the

     long-term effects of smoking and for the fact that tobacco

     smoking is such a powerful habit. Nicotine yields of cigarettes

     have declined by about 70 percent since the 1950s, largely due

     to the popularity of filter-tipped varieties. Nicotine can be

     produced in quantity from tobacco scraps and is used as a

     pesticide.


          SMOKING most commonly refers to the practice of inhaling smoke

     from the burning tobacco in a pipe, cigar, or cigarette.

     American Indians smoked pipes, and European explorers had

     introduced the practice into the Old World by the early 16th

     century.  Controversy over the health effects of smoking has

     existed since that time.



                        -WHY SMOKING IS DANGEROUS-

           Cigarette smoke contains thousands of chemical substances, many

     of which have been linked to the development of diseases.  Chemical

     substances occur in cigarette smoke as gases or as tiny particles.

          GASES in cigarette smoke that pose a great threat to health

     include Hydrogen Cyanide, Nitrogen Oxides, and, especially, Carbon

     Monoxide.  Carbon Monoxide is a poisonous gas that readily combines

     with hemoglobin, a substance in the blood that transports oxygen to

     body tissues.  Carbon Monoxide in the blood prevents oxygen from

     reaching the brain and the heart and other muscles.  Continual expo-

     sure to the high levels of carbon monoxide associated with cigarette

     smoking is believed to lead to heart disease.

          PARTICULATES in cigarette smoke are often referred to as tar

     these particulates include a variety of health damaging substances,

     of which nicotine is the most hazardous.  A thumbleful of nicotine

     about 60 milligramscould kill an adult if taken all at once.  A

     typical cigarette contains about one milligram of nicotine.  The body

     prevents the accumulation of fatal doses by quickly breaking down the

     nicotine from each cigarette.  However, nicotine raises the blood

     pressure, increases the heart rate, and contracts blood vessels near

     the skin.  Its effects on the body, along with the effects of carbon

     monoxide, may contribute to the high rate of heart disease among smo-

     kers.  Nicotine also is believed to contribute to the growth of seve-

     ral types of cancer.  Cigarette filters remove some but not all

     nicotine during smoking.


                        -HOW MANY TEENAGERS SMOKE-

          Roughly 1/3 of adult Americans smoke cigarettes, and most of

     them started in their teens.  In fact, of high school seniors who

     smoke regularly, less than 2% began in their senior year of high

     school and roughly 2/3 began by the 9th grade.  While only about 15%

     of youth aged 12-17 smoke regularly, most of them will continue to

     smoke and will learn to smoke stronger cigarettes at higher rates

     (youth smoke an average of about one-half pack-per-day compared to an

     average of about a pack-per-day for adults).  Teenage smoking is also

     of concern since smoking, along with drinking alcohol, is a major

     precursor to illicit use of other psychoactive drugs.  Many teenagers

     perceive smoking to be much more prevalent than the actual case,

     that "everyone smokes" or "it is the thing to do".  In point of fact,

     about 1 in 7 persons aged 12-18 smokes cigarettes.  The figures are

     even lower for youth involved in athletics or bound for college.
 
 

          -THE EFFECTS OF SMOKING ON OFFSPRING IF HIS MOTHER SMOKES-

          The effects of cigarette smoking on pregnancy, birth weight, and

     infant health have been studied extensively.  It appears that

     retarded growth is caused by hypoxia or decreases oxygen available to

     the fetus.  This partly due to the carbon monoxide delivered by the

     smoke inhalation.  Another effect of cigarette smoke during pregnancy

     is to increase the likelihood of spontaneous abortions.  In fact, the

     risk is almost double for women who smoke.  Smoking also increases

     the risk  of congenital malformations.  Thus, like so many other

     effects on smoking, is directly related to the amount of smoking.

     Levels of smoking are also associated with a variety of other

     complications during pregnancy and labor.  These include increased

     risk of bleeding and premature rupture of membranes.  Finally, there

     is a clear relationship between smoking during pregnancy and the

     occurance of the sudden infant death syndrome.  Babies born to

     cigarette smokers develop more slowly throughout childhood than

     babies born to nonsmokers.  They are more likely to have

     neurological disorders, physical abnormalities, and lower

     intelligence scores.  Until adolescence, children of the mothers who

     smoke 10 or more cigarettes per day remain about three to five months

     behind to children of nonsmokers in reading, mathematics, and general

     ability scores.  Cigarette smoking during pregnancy is also a

     significant risk factor for hyperkinesis in children.


                  
                                 STATISTICS


           In the early 1960s numerous clinical and laboratory  
     
     studies on smoking and disease had been made.  In 1964 a committee

     appointed by the surgeon general of the U.S. Public Health
 
     Service issued a report based on the critical review of

     previous studies on the effects of smoking.  The report
 
     concluded that most lung-cancer deaths are caused by cigarette

     smoking, which was also responsible for many deaths and

     disabilities from illnesses such as chronic bronchitis,

     emphysema, and cardiovascular disease.  One recent study

     estimated that 400,000 Americans die each year from breathing

     their own smoke.  Pregnant women who smoke may harm the fetus.

     A 1984 report by the service suggested that passive inhalation

     of smoke by nonsmokers could be harmful.  Considered

     controversial at the time, other studies have since confirmed

     these charges.  Some experts estimate that passive smoke kills

     as many as 50,000 Americans a year, and it is the third leading

     preventable cause of death, behind smoking and alcohol.

     Reports released in 1992 implicated passive smoke in both lung

     and heart problems of nonsmokers and found that children are

     particularly sensitive to passive smoke.

     Since 1964, health warnings have been mandated on tobacco

     advertising, and the use of such advertising has been

     restricted.  Most states in the United States have also passed

     laws to control smoking in public places such as restaurants

     and workplaces, where nonsmoking areas may be required.  U.S.

     airlines have prohibited smoking on flights lasting six hours

     or less.  Among the military, the U.S. Army has been

     particularly strict in imposing smoking restrictions.  The
 
     tobacco industry and many smokers regard antismoking measures

     as harassment, whereas many nonsmokers defend the measures on

     the grounds that the government has a duty to discourage

     unhealthful practices, that public funds in one form or another

     become involved in treating diseases caused by smoking.



                                 -TOBACCO-


           Tobacco is a tall, herbaceous plant the leaves of which are

     harvested, cured, and rolled into cigars, shredded for use in

     cigarettes and pipes, and processed for chewing or snuff.

     Tobacco is an important crop in almost all tropical countries

     as well as in many temperate ones.  The main source of
 
     commercial tobacco is Nicotiana tabacum, although Nicotiana

     rustica is also grown and is used in Oriental tobaccos.

     Tobacco has developed a wide range of morphologically different

     types, from the small-leaved aromatic tobaccos to the large,  

     broad-leaved cigar tobaccos.  The most practical means of

     classifying them is by the method used for curing or drying the

     leaf.







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