246 



THE RESPIRATORY SYSTEM 



of the bronchi, viz., in the outer fibrous coat or attached thereto 

 by a broad band of fibrous tissue. Moreover each bronchus is 

 accompanied by only one branch of the pulmonary artery and re- 

 ceives no capillaries from it. 



At the apex of the pulmonary lobule the pulmonary artery 

 enters with the bronchiole and immediately breaks into several 

 small twigs one for each atrium, according to Miller which sup- 



FIG. 209. FROM THE LUNG OF A CHILD. 



At a, the origin of a pulmonary venule in the wall of a lobule is shown ; at b, the 

 pulmonary venule is just coming into relation with the bronchiole. Hematein, Wei- 

 gert's elastic stain, and picro-fuchsin. Photo, x 105. 



ply the capillary networks in the walls of the alveolar ducts and 

 alveoli. The pulmonary capillaries form an exceedingly dense 

 net of anastomosing vessels in the walls of the alveoli, the meshes 

 of the capillary net being frequently, in the deeper portions of the 



