How does coughing and sneezing protect the respiratory system?

Coughing and sneezing are reflexes of the body that prevent bacteria to further damage the organs inside the body. It helps in keeping the airways clear and in healing. The two sources or passages of these natural reflexes are the nose and the mouth.  

Inside the nose, there are nasal hairs present to filter the oxygen or air that we breathe in. These are called Cilia, these are protective mechanisms of the body that trap dirt that cannot pass through the respiratory system. Sneezing is a natural reflex that clears the nose passages from obstructions that might affect the lungs. Coughing is also a natural reflex that is generated by an irritation in the tonsils, this condition is commonly viral. The tonsils are responsible for protecting the passage of dirty air into the lungs.