230 HUMAN PHYSIOLOGY. 



The cardiac branches, through filaments derived from the spinal 

 accessory, or possibly from the medulla oblongata direct, exert a 

 direct inhibitory action upon the heart. Division of the pneumo- 

 gastrics in the neck is followed by increased frequency of the 

 heart's action. Galvanization of the peripheral ends diminishes the 

 heart's pulsations, and, if sufficiently powerful, arrests it in diastole. 



The pulmonary branches give sensibility to the bronchial mucous 

 membrane and govern the movements of respiration. Division of 

 both pneumogastrics in the neck diminishes the frequency of the 

 respiratory movements, which may fall as low as four to six a minute ; 

 death usually occurs in from five to eight days. Feeble galvanization 

 of the central ends of the divided nerves accelerates respiration ; 

 powerful galvanization retards, and may even arrest, the respiratory 

 movements. 



The gastric branches give sensibility to the mucous coat, and 

 through motor or efferent fibers give motion to the muscular coat of 

 the stomach. They influence the secretion of gastric juice, and aid 

 the process of digestion. 



The hepatic branches, probably through anastomosing sympathetic 

 filaments, influence the secretion of bile and the glycogenic function 

 of the liver ; division of the pneumogastrics in the neck produces 

 congestion of the liver, diminishes the density of the bile, and arrests 

 the glycogenic function ; galvanisation of the central ends exaggerates 

 the glycogenic function and makes the animal diabetic. 



The intestinal branches give sensibility and motion to the small 

 intestines. 



Function. A great sensor nerve, which, through filaments from 

 motor sources, influences deglutition, the action of the heart, the 

 circulatory and respiratory systems, voice, the secretions of the 

 stomach, intestines, and various glandular organs, and the contrac- 

 tion of the walls of the stomach and intestines. 



Eleventh Pair. Spinal Accessory. 



The spinal accessory nerve consists of two distinct portions, the 

 medullary or bulbar, and the spinal. 



Origin. The medullary portion has its origin in nerve-cells in 

 the lower part of the nucleus ambiguous, located beneath the floor of 

 the fourth ventricle. From this origin the nerve-fibers pass forward 

 and emerge from the medulla oblongata on its lateral aspect. 



