Which anatomical feature helps move mucus-trapped pathogens toward the throat?

• A. Stomach acid
• B. Lymph nodes
• C. Cilia in the airways
• D. Bones

Answer: (C)

Mucociliary clearance moves mucus-bound pathogens toward the throat. The airway lining combines mucus-producing goblet cells with ciliated epithelial cells that beat in a coordinated wave. As mucus traps inhaled microbes, the cilia push it upward toward the pharynx, creating a continuous escalator from the lungs to the throat. When the mucus reaches the throat, it’s usually swallowed and exposed to stomach acid, which helps destroy the pathogens, or it can be expelled by coughing. This system is essential for keeping the lower airways clear of infection. Other options don’t perform this transport role: stomach acid acts after swallowing, lymph nodes filter pathogens rather than move mucus in the airways, and bones don’t participate in clearing mucus.