Bronchi: anatomical and functional
When bronchitis becomes inflamed due to irritation or infection, resulting in more difficult breathing, people with bronchitis also tend to have more mucus and phlegm.
The bronchi are the main passageway into the lungs. When someone takes a breath through the nose or mouth, the air enters the larynx. The next step is through the trachea, which carries air to the left and right bronchi.
The bronchi become smaller as they approach lung tissue and are then considered minor bronchi. These passageways then develop into small air sacs called alveoli, which exchange oxygen and carbon dioxide in the respiratory system. The primary bronchus is located in the upper part of the lung, with the secondary bronchus near the centre of the lung. The third bronchus is located near the bottom of these organs, just above the bronchi. No gas exchange occurs in any bronchi. When the bronchi become inflamed due to irritation or infection, bronchitis leads to more difficulty breathing. People with bronchitis also tend to have more mucus and phlegm than people without bronchitis.