RESPIRATION. 



175 



found in the epithelium of the posterior surface of the epiglottis, and in 

 several other situations in the laryngeal mucous membrane. 



The Trachea and Bronchial Tubes. The trachea or wind-pipe 

 extends froni the cricoid cartilage, which is on a level with the fifth cervi- 



FIG. 145. 



FIG. 146. 



FIG. 145. Outline showing the general form of the larynx, trachea, and bronchi, as seen from 

 before, h, the great cornu of the hyoid bone; e, epiglottis; , superior, and f, inferior cornu of the 

 thyroid cartilage; c, middle of the cricoid cartilage: fr, the trachea, showing sixteen cartilaginous 

 rings: 6, the right, and 6'. the left bronchus. (Allen Thomson. 1 x J^. 



FIG. 146. Outline showing the general form of the larynx, trachea, and bronchi, as seen from be- 

 hind, /i, great cornu of the hyoid bone ; t, superior, and t\ the inferior cornu of the thyroid cartilage ; 

 e, the epiglottis; a, points to the back of both the arytenoid cartilages which are surmounted by the 

 cornicula; c, the middle ridge on the back of the cricoid cartilage : tr, the posterior membranous part 

 of the trachea; 6, 6', right and left bronchi. (Allen Thomson.) J& 



cal vertebra, to a point opposite the third dorsal vertebra, where it divides 

 into the two bronchi, one for each lung (Fig. 146). It measures, on an 

 average, four or four-and-a-half inches in length, and from three-quarters 

 of an inch to an inch in diameter. 



