THE TRACHEA AND LUNGS. 



145 



the mucous membrane is concerned, but over the true vocal cords and 

 upon the epiglottis, as well as here and there in the part above the 

 glottis, stratified epithelium is found, and taste-buds (see next Lesson) 

 may occur in this epithelium, except over the vocal cords. 



FIG 167. DIAGRAMMATIC REPRESENTATION OF THE ENDING OF A 

 BRONCHIAL TUBE IN SACCULATED INFUNDIBULA. 



J3, terminal bronchus ; L.B., lobular bronchiole ; A, atrium ; I, infundibulum ; C, air-cells 



or alveoli. 



The lymphoid tissue is especially abundant in the mucons mem- 

 brane of the ventricle of Morgagni, and a large number of mucous 

 glands open into this cavity and into that of the sacculus. 



The true vocal cords are composed of fine elastic fibres. 



FIG. 168. PORTION OF A TRANSVERSE SECTION OF A BRONCHIAL TUBE, HUMAN, 

 6 MM. IN DIAMETER. (F. E. Schultze.) (Magnified 30 diameters.) 



a, cartilage and fibrous layer with mucous glands, and, in the outer part, a little fat ; in the 

 middle, the duct of a gland opens on the inner surface of the tube ; b, annular layer of 

 involuntary muscular fibres ; c, elastic layer, the elastic fibres in bundles which are seen 

 cut across ; d , columnar ciliated epithelium. 



K 



