Describe the effects of cigarette smoke on the airway.

Cigarette smoke contains a number of harmful chemicals such as Tar, Carbon monoxide and Nicotine.

Tar settles on the lining of the airway and alveoli, increasing the diffusion distance for the gases oxygen and carbon dioxide. Over time, this leads to a higher blood level of carbon dioxide and a lower oxygen level.

Cigarette smoke stimulates the goblet cells to release more mucus and paralyses/destroys the cilia on the surface of the airway, so they are unable to move the layer of mucus.

This allows more pathogens to collect and accumulate in the mucus which makes infection more likely.

The chemicals in cigarette smoke can also cause an allergic reaction - causes smooth muscle contraction in the walls of the airways - which further restricts the flow of air.