Generally, bronchitis is the irritation ad inflammation of the bronchial tubes as well as neighboring organs and tissues that are accessories in breathing. The main purpose of the bronchial tubes is to filter the air that passes through the respiratory tract as it sets out to the lungs. These tubes are covered with small hair-like projections that thwart irritants or dirt (such as dust or pollen) from entering the crucial parts of the respiratory tract. These hair-like projections are called cilia. But long term contact with chemicals, viruses, or even dust particles will facilitate these irritants to shatter the respiratory system’s natural defenses which will eventually cause infection and inflammation.