292 THE NERVOUS SYSTEM 



two main divisions. One goes to the pharynx, the Eus- 

 tachian tube, the palate, and the tonsils, as a motor nerve 

 chiefly. The other is the nerve of taste for the back part 

 of the tongue. 



10. The vagus, or pneumogastric, is the wandering nerve. 

 It is longer and has a more complicated distribution than 

 any other cranial nerve. It sends branches to pharynx, 

 larynx, esophagus, stomach, intestines, lungs, heart, liver, 

 and spleen. It is both sensory and motor. 



11. The spinal accessory, a purely motor nerve, con- 

 tains fibers from a nervous center in the walls of the 

 fourth ventricle, and from the anterior horns of the spinal 

 cord. The latter fibers pass up into the cranium and join 

 the cerebral fibers of this nerve just before it passes out 

 of the skull. The nerve has two branches, one of which 

 joins the vagus, to which it supplies motor fibers and 

 inhibitory fibers for the heart, while the other supplies 

 certain muscles of the shoulder blade and neck. 



12. The hypoglossal is connected with the vagus, Avith 

 a ganglion of the sympathetic system, and with some of 

 the upper spinal nerves. It is the motor nerve for the 

 muscles connected with the hyoid bone and the tongue, 

 and sends a branch to some muscles of the neck and chest. 

 It also contains vasomotor filaments. 



428. The Nervous End Organs have been described in 

 previous chapters, and are mentioned here to complete 

 the anatomical view of the nervous system. They are in 

 man of three classes, viz. end plates of different forms 

 found in the muscles, organs of special sensation, and 

 secreting cells found in the various glands. 



429. The Sympathetic System (Fig. 136). What is 

 commonly called the sympathetic or ganglionic system con- 

 sists of a double chain of ganglia, twenty-four upon each 



