What is the role of cilia in the respiratory system?

• A. Transport oxygen
• B. Produce mucus
• C. Filter particles
• D. Regulate airflow

Answer: (C)

Cilia play a crucial role in the respiratory system by acting as a filtering mechanism. They are tiny, hair-like structures that line the respiratory tract and are responsible for sweeping mucus, dead cells, and foreign particles out of the airways. This action helps keep the air passages clear, ensuring that the air we breathe is as clean as possible by trapping dust, microbes, and other irritants before they can reach the lungs. By facilitating this movement, cilia contribute to the overall health of the respiratory system and support its function in gas exchange.

While other options might suggest important physiological activities, they do not accurately represent the primary function of cilia. For instance, oxygen transport is primarily done by red blood cells, and mucus production is the function of goblet cells rather than cilia themselves. Regulating airflow is more related to the structures of the respiratory system, such as the bronchi and bronchioles, rather than the action of cilia.