Bronchi

Dscn1952.jpg (71659 bytes) Dscn1953.jpg (70983 bytes) Medial view, left lung

The bronchi are the large branches on both sides of the respiratory system.  There are two primary bronchi that branch from the trachea.  You will probably not see these.  However, the above dissection is at the level of the primary bronchus and you can see in the right hand picture where it bifurcates as it passes into the lung.  In that picture the probe is covering one of the openings of the secondary bronchi.  Each primary bronchus branches to secondary bronchi, one to each of the lung lobes.  Thus, there are 7 secondary bronchi in a cat, but only five in humans.  The bronchi are recognizable because of the cartilaginous rings in their walls that help keep them from collapsing.  The secondary bronchi also subdivide as they move through the lung.