CLINICAL MEDICINE

Detailed explanation-1: -Overview. The bronchus in the lungs are lined with hair-like projections called cilia that move microbes and debris up and out of the airways. Scattered throughout the cilia are goblet cells that secrete mucus which helps protect the lining of the bronchus and trap microorganisms.

Detailed explanation-2: -Cilia propel a liquid layer of mucus that covers the airways. The mucus layer traps pathogens (potentially infectious microorganisms) and other particles, preventing them from reaching the lungs.

Detailed explanation-3: -Nose. The nose has internal hairs, which act as a physical barrier to infection. Cells in the nose produce mucus which traps pathogens before they can enter the lungs. When the nose is blown, the mucus, and any pathogens that are trapped within it, is removed.

Detailed explanation-4: -Mucus acts as a physical barrier, trapping inhaled particles and pathogens, whilst cilia move both the mucus layer and fluid in the underlying periciliary layer.