Answer
Ms. Brown is experiencing dyspnea and has been diagnosed with emphysema. She has been a cigarette smoker for several years and the products of tobacco smoking--smoke, nicotine, tar, carbon monoxide-- have damaged her lungs. Typically, the products of smoking destroy alveolar walls; this produces in large spaces in the lungs, which remain filled with residual air after exhalation. The change from many small alveolar spaces to large irregular spaces reduces surface area in the lungs; this impairs the efficiency of pulmonary gas exchange, and the oxygen content of blood decreases.
Nicotine and other chemical irritants of cigarette smoke constrict terminal bronchioles; this slows air flow in and out of the lungs--an effect aggravated by loss of elasticity of lung tissues. Because air flow and gas exchange are impeded, carbon dioxide builds up in the lungs and binds to hemoglobin . This reduces the ability of the blood to transport the normal amount of oxygen.
The respiratory passages of a smoker secretes an unusual amount of mucus in response to the irritation by smoke and other chemicals. It is normally the function of respiratory cilia to clear the passages of this mucus and so get rid of the irritation. But tobacco tar and some other chemicals paralyze
and destroy the respiratory cilia ; this interferes with the ability of respiratory passages to clear themselves of the mucus and the toxins.
Work Step by Step
People with emphysema use more energy to breathe than healthy people do. This daily extra exertion weakens the respiratory muscles of emphysemic patients. Consequently, they become tired even by walking short distances.
Patients who develop chronic bronchitis--with emphysema-- are said to have chronic obstructive pulmonary disease (COPD). There is no cure for emphysema (or COPD) but bronchodilators, corticosteroids, and proper nutrition all help in slowing down the progress of the disease and making the patient feel better. Most important of all, Ms. Brown should stop smoking. Emphysema is a significant cause of mortality among Americans.
