THE RESPIRATORY ORGANS. 



2 4 7 



that the mucosa assumes the character of diffuse adenoid tissue. 

 The superficial part of the tunica propria is beset with papilhe, best 

 developed in those regions whicbj are covered with squamous epi- 



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Longitudinal section of larynx of child, exhibiting vocal cords and ventricle : a, surface above false 

 cord (b} covered with squamous epithelium ; c, true cord covered with squamous epithelium ; V, ven- 

 tricle lined with ciliated columnar epithelium ; d, ducts of mucous glands (g) cut in" various direc- 

 tions; m, fibres of thyro-arytenoideus muscle. i 



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us mu 



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thelium. ^The deeper layer of the mucous membmne is of loose 

 structure, and passes into the still looser tissue of the submucosa, 

 which serves to attach the mucous membrane with the surrounding 

 firmer structures. In places the submucous tissue contains mucous 

 follicles, .2-1 mm. in length, lined with columnar cells, many of 

 which are distended with mucous secretion, even to the condition of 



