How does lung volume affect airway resistance during breathing?

• A. Higher volume decreases resistance
• B. Higher volume increases resistance
• C. Volume has no effect
• D. Only affects larger airways

Answer: (A)

Lung volume plays a crucial role in determining airway resistance during breathing. As lung volume increases, the airways expand, leading to a decrease in the resistance that air encounters as it moves through the respiratory passages. This is primarily due to the physical laws governing airway dynamics; specifically, the relationship between volume and pressure in the airways.

When the lung volume is higher, the bronchi and bronchioles, which are the smaller airways in the lungs, are held open more effectively due to the positive pressure exerted by the expanding lung tissue. This reduction in airway resistance allows for easier airflow during both inhalation and exhalation. In contrast, lower lung volumes can lead to airway constriction, increasing resistance and making breathing more laborious.

Understanding this relationship is important in clinical settings, especially for individuals with respiratory conditions, where managing airway resistance can significantly influence breathing efficiency and overall respiratory health.