176 THE ENGINES OF THE HUMAN BODY 



learn when we see men or women in whom disease has 

 damaged the controlling nerve centres in the medulla ; 

 all attempts at swallowing end in choking and spluttering. 

 The reflex or " touch-the-button " mechanisms of the 



BASE of SKULL 



LARYNGEAL OPENING, 

 (Closed) 



LARYNX 



TRACHEA 



OESOPHAGEAL 

 OPENING 



OESOPHAGUS 



Fig. 37. — Diagram showing a bolus of food within the pharynx, in the 

 act of being forced into the oesophagus. 



pharynx have broken down. That such people may live 

 food must be poured directly into the oesophagus by 

 means of a tube attached to a funnel or filler. 



A bolus of food is carried rapidly through the pharynx, 

 but its transport in the oesophagus is leisurely. In fig. 38 

 a representation is given to show the manner in which the 



