Asbestos Hazard Emergency Response Act (AHERA) Certification Practice Exam

Which of the following best describes the role of cilia in the respiratory system?

1. Filtering the air before it enters the lungs

2. Facilitating gas exchange in the alveoli

3. Helping to transport mucus out of the lungs

4. Protecting against viral infections

The correct answer is: Helping to transport mucus out of the lungs

Cilia play a crucial role in maintaining respiratory health by helping to transport mucus out of the lungs. In the respiratory system, cilia are tiny hair-like structures that line the airways. Their primary function is to move in a coordinated manner to propel mucus, which traps dust, pathogens, and other particles, upward toward the throat where it can be swallowed or expelled. This process is essential for keeping the airways clear and preventing the accumulation of harmful substances that could lead to infections or respiratory issues. In contrast, while filtering air before it enters the lungs is an important function of structures like nasal hair and the mucus layer, it is not specifically the role of cilia. Gas exchange occurs in the alveoli, but this process does not involve cilia. Although some components of the respiratory system do play a role in protecting against infections, the primary function of cilia is not directly related to preventing viral infections but rather to clearing debris and pathogens from the respiratory tract. Thus, the choice emphasizing the transport of mucus accurately reflects the role of cilia in respiratory physiology.