What is the function of the bronchi in the respiratory system?
The bronchi, singularly known as a bronchus, are extensions of the windpipe that shuttle air to and from the lungs.
Think of them as highways for gas exchange, with oxygen going to the lungs and carbon dioxide leaving the lungs through them. They are part of the conducting zone of the respiratory system. The conducting zone, which includes the windpipe and pharynx, is a region of the respiratory system that only moves air in and out of the body and is not a part of the gas exchange process.
Each bronchus contains cartilage, a mucosal lining, and smooth muscle. Cartilage is a connective tissue that provides support for physical processes, and in this case, it prevents the collapsing of the bronchi during inhalation and exhalation. This is important, since air conduction involves pressure that can damage soft tissue if not protected. The mucosal lining produces mucous, which is a thick, semi-liquid substance designed to trap foreign particles from entering the lungs.
Smooth muscle is also found in each bronchus. It is muscle that is involuntarily controlled, which means you can't control it yourself. Your body determines whether this smooth muscle contracts or relaxes based on whether or not more or less airflow is needed.