Question

Which of the following changes can an emphysema patient experience?

• A. Increased blood oxygen concentration
• B. Increased residual volume
• C. Decreased blood carbon dioxide concentration
• D. Decreased total lung capacity

Answer 1

The correct option is B Increased residual volume

An emphysema patient suffers from damaged alveolar walls (the outer layer of air containing pouches present in lungs). This leads to a decrease in the respiratory surface. Cigarette smoking is one of the leading causes of this respiratory disorder.
The lungs are a pair of spongy, air-filled organs located on both sides of the chest in humans. The walls of the lungs are such that they can easily deflate during exhalation. Such a property of the lungs is termed as elastic recoil of lung tissue. This property helps in reducing the lung volume. As the lung tissue i.e. alveolar walls are damaged, there is decreased recoil. It leads to difficulty in exhaling completely, which increases the residual volume (air volume that cannot be expelled from lungs after forced exhalation).
Total lung capacity is the total volume of air present in the lungs after forced inhalation. As mentioned earlier, elastic recoil is reduced in an emphysema patient. There is less recoil after inhalation i.e. less opposition to inhalation, thus increasing the total lung capacity.
Now since the alveolar wall is damaged, the surface area in the alveoli is also reduced. It reduces the gaseous exchange that results in a decrease in the oxygen concentration in the blood and increases the carbon dioxide concentration in the blood as the body tissues continuously use up oxygen and expel carbon dioxide in the blood.