DIGESTION 287 



tion independently of the presence of food or liquid ; but if 

 the central end of the glosso-pharyngeal nerve be stimulated 

 at the same time, the movements do not occur. The glosso- 

 pharyngeal is therefore able to inhibit the deglutition centre, 

 and it is probably owing to the action of this nerve that in a 

 series of efforts at swallowing, repeated within less than a 

 certain short interval (about a second), only the last is 

 successful. 



The efferent nerves of the reflex act of deglutition are the 

 hypoglossal to the tongue and the thyro-hyoid and other 

 muscles concerned in raising the larynx ; the glossc-pharyn- 

 geal, vagus, facial and fifth to the muscles of the palate, 

 fauces, and pharynx ; the fifth to the mylo-hyoid ; and the 

 vagus to the larynx and oesophagus. Section of the vagus 

 interferes with the passage of food along the oesophagus ; 

 stimulation of its peripheral end causes cesophageal move- 

 ments. 



/<- Movements of the Stomach and Intestines. The whole of the 

 ^stomach does not take part equally in the movements asso- 

 ciated with digestion. We may divide the organ, both 

 anatomically and functionally, into two portions a pyloric 

 portion, or antrum pylori, and a larger cardiac portion, or 

 fundus.* At the junction of the antrum and the fundus the 

 circular muscular coat is thickened into a ring called the 

 ' transverse band,' or ' sphincter of the antrum.' When the 

 stomach is empty it is contracted and at rest. A few minutes 

 after food is taken contractions begin in the antrum, and run 

 on in constricting undulations (in the cat at the rate of six in 

 the minute) towards the pyloric sphincter. Feeble at first* 

 they become stronger and stronger as digestion proceeds, 

 and gradually come to involve the portion of the fundus 

 next the sphincter of the antrum, but apparently their 

 direction is always towards the pylorus, never, in normal 

 digestion, away from it. The food is thus subjected to 

 energetic churning movements in the pyloric end of the 



* Here ' fundus ' is used in the sense in which it is generally employed 

 in speaking of the stomach of the dog or cat as signifying ihe whole of the 

 organ with the exception of the antrum pylori. The fundus of the human 

 stomach is, properly speaking, only the cul-de-sac at the cardiac end ; the 

 portion intervening between it and the antrum pylori is often termed the 

 body of the stomach. 



