d. Disease Processes of Lungs or Component Parts.
(1) Lung cancer. People inhale many irritating substances as a part of
ordinary breathing. Inhaled smoke and almost all pollutants have an irritating effect on
the bronchial tubes and lungs. These pollutants act as stresses or irritating stimuli. A
common lung cancer, bronchogenic carcinoma, starts in the walls of the bronchi and is
caused by stress and irritation.
(2) Nasal polyps. These polyps, protruding growths of mucous membrane
hanging down from the posterior wall of the nasal septum, are bluish-white tumors. As
they become larger, they may fill the nasopharynx making breathing through the nose
difficult. A doctor can remove these polyps easily.
(3) Bronchial asthma. Usually, bronchial asthma is caused by an allergy to
edible or air-borne substances--for example, wheat or dust. Muscles in the walls of the
small bronchi and bronchioles go into spasms caused by the allergy. Also, the smaller
bronchi and bronchioles may be clogged with excessive amounts of mucous making
(4) Bronchitis. Bronchitis is inflammation of the bronchi. The most
important cause of chronic bronchitis is cigarette smoking. (Chronic bronchitis is
bronchitis that lasts for at least three months of the year for two successive years.)
(5) Emphysema. In this disease, the alveolar walls lose their elasticity and
remain filled with air during expiration. The word "emphysema" means "blown up" or
"full of air." A person with emphysema must actively work to exhale. Also, as a result of
damage to the alveolar-capillary membrane, the respiration rate slows down. Removing
the irritating stimuli-- air pollution, occupational exposure to dust, cigarette smoking--can
(6) Pneumonia. Pneumonia is an acute infection or inflammation of the
alveoli. The amount of air space in the lungs is reduced because the alveolar sacs fill
up with fluid and dead white cells. A bacteria called pneumococcus bacterium is the
most common cause of this disease, but other bacteria or a fungus may also cause
pneumonia. Several viruses may cause viral pneumonia.
(7) Tuberculosis. Tuberculosis is caused by bacteria-- Mycobacterium
tuberculosis--which destroys parts of the lung tissue. Tuberculosis bacteria are spread
by inhaling, can live through some disinfectants, but are killed by sunlight. This disease
is sometimes associated with crowded, poorly lit housing. A person with tuberculosis
must have rest, sunlight, and good diet.