Begriff=Lower respiratory tracts; continuation of the trachea (windpipe). Before the 4th thoracic vertebra, the bronchus divides into the right and left main bronchi. The main bronchi then branch into the lobes of the lung, with three lobe bronchi on the right and two on the left. These then branch into segmental bronchi, corresponding to the number of lung segments. <br>The wall of the bronchi is covered with a ciliated epithelium. In the wall of the ciliated epithelium there are beaker cells which secrete mucus, which is transported in the direction of the throat by the cilia. In this way, foreign particles are transported out of the bronchi. Bronchial musculature is smooth and circular and forms helixes in the smaller bronchi.  Cf. [197; bronchioles</a></font>.