SENSE ORGANS. 



205 



130), that the passage of the food from the mouth to the 

 stomach and of the air from the nostrils to the lungs 

 cross one another in the throat. Therefore there must 

 be a valve which shall close the larynx when the food is 

 passing, otherwise the food, especially liquids, would fall 

 into the larynx in swallowing. This would produce great 

 irritation and pain. This valve is the epiglottis. When 

 we swallow, the larynx is drawn up by certain muscles 

 with great force toward the roof of the throat. In this 

 position the food in passing presses down the epiglottis 

 and closes perfectly the open- 

 ing of the larynx. The rela- Jk e Q0 



tion of the epiglottis to the 

 larynx is seen in Fig. 131. 



Fig. 130. — Section of head, show- 

 ing the relations of the air pas- 

 sage and the food passage : g, 

 gullet ; rr, trachea ; cr, the point 

 of crossing. 1 



cr- 



Fig. i^i. — Side view of larynx : hy, 

 hyoid ; epg, epiglottis ; th, thy- 

 roid ; cr, cricoid ; a, arytenoid. 

 The different parts are seen in 

 transparency. 



At the junction of the epiglottis with the larynx there 

 are a kind of cords (false vocal cords), which are sup- 

 posed to have some function in modifying the voice. 



Experiment. — Put your finger on the Adam's apple 

 (larynx), and try to hold it down while you swallow. You 

 will find it impossible. It rises in spite of your effort. 



