What triggers a cough?

Cough receptors are located in the walls of the body’s airways and are triggered by irritants such as dust or smoke, microorganisms or conditions like asthma.

The receptors trigger an impulse that runs along the vagus nerve to the cough centre, which is located in the medulla oblongata of the brain.

This in turn sends nerve impulses to the respiratory muscles, causing a sudden inhalation of air. This air becomes momentarily trapped in the lungs as the glottis and vocal cords in the throat close.

The intercostal muscles between the ribs, the abdominal muscles and the diaphragm then contract and force air out, causing the glottis and vocal cords to reopen. The pressure of the air as it leaves the body, hopefully taking with it the irritant, causes the sensation – and characteristic noise – of a cough.