The maintenance of normal lung volume is primarily influenced by which factor?

• A. Airway resistance
• B. Alveolar pressure gradients
• C. Compliance of lung tissue
• D. Pleural space pressure

Answer: (C)

The maintenance of normal lung volume is primarily influenced by the compliance of lung tissue. Compliance refers to the ability of the lung to stretch and expand during inhalation. High compliance indicates that the lungs can expand easily, while low compliance means they are stiffer and require more effort to inflate.

When the lung tissue is compliant, it can efficiently accommodate the volume of air that enters during each breath, facilitating effective gas exchange. This property is crucial for maintaining normal lung volumes, as it directly affects how well the lungs can expand with each inhalation.

Other factors such as airway resistance, alveolar pressure gradients, and pleural space pressure do play significant roles in the overall mechanics of breathing, but they do not primarily dictate the ability of the lung tissue to expand and accommodate air. For example, while airway resistance can affect airflow, it does not directly influence the elastic properties of lung tissue. Similarly, alveolar pressure gradients are important for driving gas exchange but are not the main determinant of lung volume maintenance. Lastly, pleural space pressure is vital for keeping the lungs inflated against the thoracic wall, but again, it does not primarily dictate lung tissue compliance.