Respiration 



16 



four and one-half inches long, called the larynx. It contains 

 the organ of voice and is more fully described in Chapter XII. 



The upper end of the larynx opens into the pharynx, or 

 throat, and is provided with a kind of lid, the epiglottis, 

 (sec. 156 and Fig. 45). 



247, The Trachea, or 

 Windpipe. The continua- 

 tion of the larynx is the 

 trachea, a tube about three- 

 fourths of an inch in diam- 

 eter and about four inches 

 long. It extends down- 

 wards along the middle line 

 of the neck, where it may 

 readily be felt in front, be- 

 low the Adam's apple. 



The walls of the wind- 

 pipe are strengthened by a 

 series of cartilaginous rings, 

 each somewhat the shape 

 of a horseshoe or like the 

 letter C, being incomplete 

 behind, where they come in 

 contact with the oesophagus. 

 Thus the trachea, while 

 always open for the passage 



FIG. 84. Larynx, Trachea, and the 

 Bronchi. (Front view.) 



of air, admits of the disten- 

 tion of the food passage. 

 >248. The Bronchial 

 Tubes. The lower end of 

 the windpipe divides into two branches called bronchi. Each 

 branch enters the lung of its own side and breaks up into 

 a great number of smaller branches called bronchial tubes. 



, epiglottis ; B, thyroid cartilage ; C, crico- 

 thyroid membrane, connecting with the cri- 

 coid cartilage below, all forming the larynx; 

 D, one of the rings of the trachea. 



