DIGESTION OF FOOD IN THE MOUTH 



61 



ments, aided by the movements of the lips and cheeks, keep the food 

 in the best position for the action of the teeth. In a few seconds, even 

 hard and dry food becomes a thin and pasty mass. The tongue col- 

 le'cts the mass into a ball in the back part of the mouth in preparation 

 for its passage to the stomach. The process of sending food from the 

 mouth to the stomach is swal- 

 lowing w deglutition. 



81. The pharynx. 

 Back of the tongue is a 

 muscular bag about four 

 and a half inches in 

 length, lying against the 

 spinal column and called 

 the pharynx. It is lined 

 with mucous membrane, 

 which secretes far more 

 mucus than that of the 

 mouth. When the secre- 

 tion of mucus is excessive 

 it is called catarrh, but it 

 is usually a harmless 

 affection. The pharynx 

 has seven openings; one 

 into the esophagus or 

 muscular tube leading to 

 the stomach ; one into 

 the ^beginning of the 

 windpipe ; one into the mouth ; two into the nose, and two 

 into the middle ear. The openings to the nose and ears 

 can be closed by raising the soft palate against the spinal 

 column. The windpipe can be closed in three ways : 

 first, by the root of the tongue arching itself backward 

 over the windpipe; second, by a cover to the windpipe, 

 called the epiglottis ; third, by the vocal cords sliding 



Diagram of the beginning of swallowing. 



a top of tongue. 



b pharynx. 



c morsel of food. 



d sliding door of the front of the pharynx. 



e soft palate. 



/ epiglottis. 



