364 



HOW FOOD IS PREPARED FOR BODY USE 



to the back, called the soft palate. These separate the nose 

 cavity from that of the mouth. The space back of the soft 

 palate is called the pharynx, or throat cavity. From the pharynx 



.hard palate 

 soft palate 



.- uvulae 



..-nccr-ee 



...vomer 



.--Eustachian - 



"tube 

 —esophagus--! 

 '—glottis 

 — tongue - 



Comparison between the mouth of frog and of man. 



lead off the gullet and trachea or windpipe. There are also open- 

 ings here to the Eustachian tubes and to the nose. The lower 

 part of the mouth cavity is occupied by a muscular tongue. The 

 tongue is used in moving food about in the mouth, and in starting 



it on its way to the 

 gullet. 



Laboratory Exercise. 

 What conditions are 

 favorable or unfavor- 

 able for the digestion 

 of starch? Place in 

 test tubes an equal 



. i . m amount of starch paste, 

 epiglottis- In the firgt tube add 



water ; to a second, 

 saliva; to a third, 

 saliva and a few drops 

 of weak acid ; to a 

 fourth tube saliva and 

 a base such as weak 

 sodium hydroxide. 

 Place all these tubes 

 in water of about 

 99° F. for 20 minutes. 

 Test the contents of 



hard 

 soft 



A longitudinal section through the head, showing the 

 throat and its connections. How is the throat connected 

 with the nose ? with the stomach? with the lungs ? 



