A bronchus (plural bronchi, adjective bronchial)'s a passage of airway in the respiratory tract that conducts air into the lungs. No gas exchange takes place in this part of the lungs. Anatomy The trachea (windpipe) divides into two main bronchi (also mainstem bronchi), the left and the right, at the level of the sternal angle at the anatomical point known as the carina. The right main bronchus's wider, shorter, and more vertical than the left main bronchus. The left main bronchus subdivides in… (More on Bronchi)