CRANIAL NERVES. 113 



sympathetic filaments, which join the pneumogastrics high up in the neck, 

 give motion to the muscular coat of the stomach. They influence the 

 secretion of gastric juice, aid the process of digestion and absorption from 

 the stomach. 



The Hepatic branches, probably through anastomosing sympathetic fila- 

 ments, 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 ; galvanization of the central ends exaggerates the glycogenic 

 function, and makes the animal diabetic. 



The Intestinal branches give sensibility and motion to the small intes- 

 tines, and when divided, purgatives generally fail to produce purgation. 



Function. A great sensitive nerve, which, through anastomotic fila- 

 ments 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. 



nth Pair. Spinal Accessory. 

 Apparent Origin. By two sets of filaments: 



1. A bulbar or medullary set, four or five in number, from the lateral or 

 motor tract of the lower half of the medulla oblongata, below the origin of 

 the pneumogastric. 



2. A spinal set, from six to eight in number, from the lateral portion of 

 the spinal cord, between the anterior and posterior roots of the upper four or 

 five cervical nerves. 



Deep Origin. The medtdlary portion arises in a nucleus in the lower 

 half of the floor of the 4th ventricle, common to the pneumogastric and 

 glosso pharyngeal nerves. The spinal portion has its origin in an elongated 

 nucleus lying along the external surface of the anterior cornua of the spinal 

 cord, extending down to the 5th cervical vertebra. 



Distribution. From this origin the fibres unite to form a main trunk, 

 which enters the cranial cavity through the foramen magnum, where it is 

 at times joined by fibres from the posterior roots of the two upper cervical 

 nerves, and sends filaments to the ganglion of the root of the pneumo- 

 gastric. After emerging from the cranial cavity through the jugular fora- 

 men, it sends a branch to the pneumogastric, and receives others in return, 

 and also from the 2d, 3d and 4th cervical nerves. It divides into two 

 branches: (i) An internal or anastomotic branch, made up of filaments 

 coming principally from the medulla oblongata, and is distributed to the 



