Bird, lung (LM, Medium)

Structure List Parabronchus Atria Blood capillaries Muscular pillars Air capillary

This field shows a cross section of a parabronchus and its associated gas exchange area. Note the muscles in the walls of the parabronchus. These muscular pillars separate atria from each other. From the atria, the air capillaries project into the surrounding vascular bed. At high magnification, attempt to identify air capillaries and blood capillaries in the parenchyma. What type of epithelium lines the surface of the smooth muscle bundles? The red blood cells are nucleated.