The pseudostratified ciliated columnar epithelium of the trachea the pseudostratified ciliated columnar epithelium of the trachea lines the airway that is held open by c-shaped cartilaginous rings produces mucus to trap dust particles, bacteria, and other debris produces mucus to trap dust particles, bacteria, and other debris; sweeps the mucus toward the throat, where it can be expelled or swallowed; and lines the airway that is held open by c-shaped cartilaginous rings sweeps the mucus toward the throat, where it can be expelled or swallowed