• The function of the tracheal cilia is to pass mucus out. Tracheal cilia beat upward toward the pharynx to remove dust and trapped particles in mucus.

• The tracheae, primary, secondary and tertiary bronchi, and initial bronchioles are supported by incomplete cartilaginous rings.

• Pulmonary ventilation is always more than that of alveolar ventilation.

• Minute (pulmonary) ventilation tidal volume × respiratory rate. Alveolar ventilation (tidal volume - dead space) × respiratory rate. Because of physiological dead space, pulmonary ventilation is greater than alveolar ventilation.

• Typical value of total lung capacity of an adult human being is 6 liters (varies with sex, age, body size).