Chap. XIII] 



RESPIRATORY SYSTEM 



237 



round, while during the production of a high note the edges of 

 the folds approximate so closely as to leave scarcely any open- 

 ing at all. 



fiiiperior 

 Horn 



Inferior 

 Horn 



Fig. 143. — Front View of Cartilages of Larynx. Trachea and Bronchi. 



Voice. — The vocal cords produce the voice. A blast of air, 

 driven by an expiratory movement out of the lungs, throws the 

 two elastic cords into vibrations. These impart their vibrations 

 to the column of air above them, and so give rise to the sound 



