62 



APPLIED PHYSIOLOGY 



together in the middle. The opening to the mouth can 

 be closed by two upright muscles which hang between the 

 back part of the soft palate and the base of the tongue. 



These two muscles come 

 together in the middle 

 like sliding doors. 



82. Swallowing. By 

 a conscious effort, the 

 tongue quickly pushes the 

 morsel of food backward 

 towards the pharynx. The 

 two upright muscles of 

 the pharynx, gliding to- 

 gether over the surface of 

 the tongue between it and 

 the food, cut the food off 

 from the mouth. During 

 this movement the phar- 



ynx closes all its other 

 ; t the Qne 



to the esophagus. The 

 f ood fe now beyond the 



* 

 Control of the WllL The 



Diagram of second part of swallowing. 



a top of tongue arched backward and up- 

 ward. 



b pharynx. 



c morsel of food pushed into the pharynx by 

 the back of the tongue. 



d sliding doors of .^e pharynx which have muscles o f the pharynx 



come together in the middle. f J 



e soft palate lifted upward to shut off the nose, itself now Contract, for- 



f ^ilrynx. ^^ downward to close the cing the food into the 



esophagus, the opening 

 of which is the only one not closed. 



83. The esophagus. The esophagus is a muscular 

 tube connecting the pharynx with the stomach. It is 

 about nine inches in length. It is lined with mucous 

 membrane and secretes only enough mucus to moisten its 

 surface. When food reaches it, a ring of the muscular 



