Figure 5. Images of alveolar walls taken from semi-thin (1–2 µm) sections stained with Toluidine Blue.

A, alveolar wall taken from control lung with numerous capillaries discernible within the alveolar wall. B, alveolar wall taken from chronically hypoxic lung tissue. Some capillaries appear to protrude from alveolar wall into alveolar lumen, a pattern not seen in control lungs. Scale bars indicate 10 µm.