262 Unit 4 Understanding and Avoiding Hazardous Substances
Copyright Goodheart-Willcox Co., Inc.
Chronic bronchitis is an ongoing condition in which the bronchial
tubes become swollen and irritated. Smoking causes the mucous mem-
brane in the lungs’ bronchial passages to become infl amed, which narrows
the pathway to the lungs. This makes it increasingly diffi cult for the lungs
to take in enough oxygen, which is why people with bronchitis often expe-
rience coughing spells and have diffi culty catching their breath. Smoking
and inhaling secondhand smoke are primary causes of chronic bronchitis,
but regularly inhaling air pollution and smoke from tobacco products con-
tributes to the condition as well.
Emphysema is a disease that causes the airways in the lungs to be-
come permanently enlarged. Emphysema destroys the sacs of air that
make up lung tissue (alveoli), which is where oxygen and carbon dioxide
are traded during the breathing process. The destruction of the alveoli
makes it more diffi cult to breathe. As a result, the person has to breathe
faster to get enough oxygen into the lungs and into the bloodstream. This
extra work places a burden on the heart, leading to more health problems
(Figure 9.4).
Asthma and Other Illnesses. Asthma is a chronic disease caused by
blockages of the airfl ow to and from the lungs. When a person with asthma
inhales tobacco smoke—either by smoking a cigarette or by being around
people who are smoking—the lining of the airways becomes irritated.
This irritation can then cause an asthma attack. Moreover, because tobacco
smoke damages the cilia, they are unable to eliminate unwanted particles
in the lungs. This means these particles stay in the airways and continue to
trigger asthma attacks.
Similarly, smoking interferes with a person’s ability to participate in
even casual forms of physical activity. For example, after beginning to
smoke, someone who once ran one lap around the track without becoming
out of breath may be breathless after running half as far. This is because
smoking leads to reduced lung capacity, and the hearts of smokers are al-
ready overworked before they begin physical activity.
Smoking also leads to a weakened immune
system. Your immune system consists of the or-
gans, tissues, and cells in the body that help
defend itself from disease-causing agents such
as bacteria, parasites, and viruses. Smokers are
at greater risk of becoming ill from germs that
cause colds and the fl u.
Tobacco use can lead to a number of other
health problems. Smokers have a higher risk
factor than nonsmokers for developing osteo-
porosis, ulcers, fertility problems, and gum
disease. Tobacco use can also interfere with
eating by changing the shape of taste buds.
When food does not taste as good, some long-
term smokers lose their appetite and interest
in eating.
chronic bronchitis
a condition in which the
bronchial tubes swell and
become irritated
Below, on the left, is a
healthy, normal lung. On
the right is a smoker’s lung,
which has been damaged
in many ways. For example,
constant irritation from the tar
in smoke keeps a smoker’s
lungs infl amed, resulting in
a buildup of scar tissue that
reduces the lung’s elasticity.
Figure 9.4
emphysema
a disease that permanently
enlarges lung airways
and destroys lung tissue,
making it diffi cult for a
person to breathe
asthma
a chronic disease
characterized by episodes
of blocked airfl ow to the
lungs
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