Bronchi help transport air to and from the lungs; they send oxygen to the lungs and allow carbon dioxide to exit the lungs. The bronchi are a part of the respiratory tract that act as an extension of the windpipe.
At the end of the trachea are a right bronchus and a left bronchus. These bronchi play a major role within the conducting zone of the respiratory system. This zone includes the pharynx and the windpipe, which helps move air in and out of the body. The bronchial tubes travel through the lungs and separate into smaller airways known as bronchioles. In the bronchi, air is transported, but there is not a gas exchange.