What is the role of cilia in the respiratory system?

• A. Assist in gas exchange
• B. Help produce sound
• C. Keep air passages clean
• D. Facilitate movement of the diaphragm

Answer: (C)

Cilia play a crucial role in maintaining the cleanliness of the air passages within the respiratory system. These tiny hair-like structures are located on the surface of epithelial cells lining the respiratory tract. Their primary function is to sweep mucus and trapped particles, such as dust, pollen, and pathogens, out of the airways. This mucociliary clearance mechanism is essential for protecting the lungs from infection and irritation, as it helps to prevent harmful substances from reaching the alveoli, where gas exchange occurs.

By generating coordinated, wave-like motions, cilia effectively move mucus towards the throat, where it can be swallowed or expelled. This cleaning process ensures that the air we breathe is as free as possible from contaminants, contributing to overall respiratory health. The other functions mentioned in other choices do not pertain to the primary role of cilia within the respiratory system.