DEFENCE MECHANISMS OF THE LUNGS

Healthy lungs have effective ways to keep clean. Mucus in the airways traps dirt and foreign particles. Little hairs called cilia beat back and forth in the airways to move the mucus and dirt up where it can be expelled by coughing.

There are also special cells in the airways called macrophages. Macrophages are mobile cells that eat up toxins in the airways and lungs.

There are two requirements for this system to work:

• a regular supply of air containing oxygen must be inhaled via open, clear airways in order to reach the air sacs
• the waste gas, carbon dioxide, must be exhaled through these same airways

SMOKING destroys all these defenses.

• smoke consists of hundreds of chemicals that act as toxins to our lungs
• smoke increases mucus production, but it also stops the little hairs or cilia from working

How Our Lungs Work

Chronic Bronchitis