HOW DUST IS PREVENTED FROM ENTERING THE LUNGS

The respiratory system prevent harmful substances in the air from entering the lungs using the following built-in structures:

·         Hairs in your nose help filter out large particles.

·         Cilia (microscopic hairs), found along the air passages, move in a sweeping motion to keep the air passages clean. They sweep in such a way that they bring the particle toward the throat to be coughed out.

·          Mucus produced by cells in the trachea and bronchus moisten the air passages. It also helps to trap dust, bacteria and viruses, and other substances that were not trapped by the hairs from entering the lungs.

·         With the aid of the cilia, impurities that reach the deeper parts of the lungs are moved up via mucous and coughed out or swallowed.

·         The condition called bronchitis (inflammation of the bronchi) occurs if harmful substances, such as cigarette smoke, are inhaled and the cilia stop functioning properly.