Question

What role do cilia play in the respiratory tract?

Options

• They secrete lysozyme to kill bacteria

• They engulf pathogens through phagocytosis

• They release histamine to increase blood vessel permeability

• They sweep trapped microbes and mucus outward

Answer 1

Cilia are hair-like projections in the respiratory tract that function as part of the first-line physical defence by sweeping trapped microbes and mucus outward, preventing pathogens from entering the lower respiratory system and establishing infection.