How does the cough reflex defend against respiratory pathogens in the upper airways?

There are three phases of Cough Inspiratory phase – rapid inhalation of up to 2.5L of air. Compression phase – closure of epiglottis and larynx, combined with contraction of the chest wall, diaphragm and abdominal muscles. This generates intrathoracic pressure of >100mmHg. Expiratory phase – the larynx and epiglottis suddenly open, resulting in a high expiratory flow. Rapidly moving air carries dislodged mucus and removes any foreign matter.