Pulmonary Physiology, Metabolic & Defense Systems of the Lung, Dr. D. Penney

Figure 13.02. Ciliary action and mucous movement.

Mucous with trapped materials is propelled mouthward by forward ciliary strokes. The recovery stroke of the cilia occur within the lower periciliary layer. The cilia do not extend into the airway lumen, i.e. the air stream.