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HUMAN LUNG 133 



HUMAN LUNG SECTION SHOWING A SINGLE 

 ALVEOLUS (Fig. 90) 



OBSERVE : 

 (L.) 



1. The outline of alveolus. (The alveoli in human lung will 

 show much distortion, as the tissue cannot be secured in perfect 

 condition.) 



FIG. 90. TRANSVERSE SECTION OF A SINGLE PULMONARY ALVEOLUS. STAINED 

 WITH H^EMATOXYLIN (X 400). 



A. A, A. Walls of alveolus. 



B. Lumen. 



C. C, C. Capillaries variously sectioned in their tortuous course. 



D. Pavement epithelial cells intact. 



E. Detached pavement cell. 



F. Detached cluster of pavement cells. 

 F'. Granular lining cells. 



G. Pulmonary artery. 



(H.) 



2. The fibrous wall, A, A. 



3. The lumen, B. (The bottom or top has been cut off in 

 making the section.) 



4. The tortuous capillaries, C, C, in the fibrous wall. 



