Emphysema causes alveolar dilation and destruction of alveol

Emphysema causes alveolar dilation and destruction of alveolar walls which causes an increase in residual volume with air that cannot be exhaled. Assuming that an individual\'s TLC does not change, explain why a person with developing emphysema is not short of breath while resting, but becomes short of breath after climbing a flight of stairs.

Solution

Pulmonary emphysema is a disease caused in air spaces of lung distal to terminal bronchioles. The air spaces are enlarged and their walls are damaged. The disease is an important cause for disability and death. The incidence of emphysema is increasing at rapid rate. In emphysema fine alveolar structures of lungs are damaged. Large cystic air spaces are formed throughout the lung. The process begins at upper lobes and affects all lobes in both the lungs. Chronic inflammation of terminal bronchioles is observed.

Emphysema and chronic bronchitis are frequently considered as chronic obstructive pulmonary disease or COPD. The COPD is resulted in dyspnea and cyanosis. Dyspnea is shortness of breath and cyanosis is resulted by blue tinge of skin and mucous membrane due to excessive amount of reduced hemoglobin in the blood. The reduced hemoglobin is dark purplish red in color. COPD causes inflammation and narrowing of terminal bronchioles, dilation of pulmonary air spaces and loss of lung elasticity. These disturbances may lead to severe impairment in pulmonary function.

The pulmonary emphysema can be prevented by avoiding smoking and inhalation of polluted substances that are injurious to lungs. Air pollution increases the incidence of emphysema. In pulmonary emphysema, the breathing is not difficult during rest but becomes more difficult when doing strenuous activities like climbing stairs. This is because, the air volume and breathing rate increase proportionately. The tidal volume of air reaches plateau at higher intensities and inturn result in increased rate of respiration due to decreased ventilation. The air locked in alveolar pouches causes stress and becomes difficult for individual to take normal breathing. Therefore, person with emphysema struggles with shortness of breath after climbing a flight of stairs.