What change occurs in the lungs if there is a reduction in ciliary function due to smoking?

• A. Increased ability to clear mucus
• B. Decreased mucus production
• C. Increased risk of infections and impaired clearance
• D. Enhanced gas exchange

Answer: (C)

When ciliary function in the lungs is reduced, especially due to the effects of smoking, the primary consequence is an increased risk of infections and impaired clearance of mucus and debris. Cilia are tiny hair-like structures lining the respiratory tract that play a critical role in keeping the airways clear by moving mucus and trapped particles out of the lungs. This process is essential for maintaining healthy lung function and preventing infections.

With diminished ciliary activity, mucus can accumulate within the airways. The stagnant mucus provides an ideal environment for pathogens to thrive, leading to a higher susceptibility to respiratory infections such as bronchitis and pneumonia. Additionally, the impaired clearance means that not only is mucus not effectively removed, but also that particulates and irritants introduced through smoking cannot be cleared efficiently, further compounding lung issues.

In contrast, the other options imply outcomes that would not occur as a result of reduced ciliary function. For instance, increased ability to clear mucus and enhanced gas exchange would not be observed due to the dysfunction caused by smoking. Decreased mucus production is typically not an outcome of impaired ciliary function; in fact, the chronic irritation from smoking often leads to increased mucus production as a compensatory response.