NICOTINE
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                                  SMOKING
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           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 nicotineÄ
     about 60 milligramsÄcould 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
     occurrence 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 Nicotiniana tabacum, although Nicotiniana
     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.
~GREY.PAL~
