Lung bronchus and lobe anatomy, illustration. The human lungs are divided into lobes, with different lobes served by different lungs airways (bronchi). At left, the upper, middle and lower lobes are labelled. At right, the primary, secondary and tertiary bronchi are labelled showing how the bronchi branch into smaller airways the deeper they go into the lungs. Each secondary bronchus is also called a lobar bronchus (as it branches to the different lobes). Each tertiary bronchus is also called a segmental bronchus (as it branches to the segments that make up each lobe). Different lobes and segments are affected by different diseases, with the overall effect of a disease determined by the areas of lung it has affected. The trachea (windpipe) is also shown.