Dr. Richard Kessel

Image 47 of 116
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Cross-section view of an alveolus in the lung, showing a capillary with an enclosed red blood cell or erythrocyte in the interalveolar septum, several interalveolar pores, and several alveolar macrophages or phagocytes on the inner surface.  The alveoli are the sites of gas exchange. Macrophages help to keep the lungs free of foreign substances. SEM X2,195 **On Page Credit Required**