352 THE NERVOUS SYSTEM 



ganglion fibers go to the intrinsic musculature of the eye. Some of the fibers 

 arising in the sphenopalatine ganglion go to the blood-vessels in the mucous 

 membrane of the nose. Fibers from the otic ganglion reach the parotid gland. 

 And those arising in the submaxillary ganglion end in the submaxillary and 

 sublingual salivary glands (Fig. 250). 



IMPORTANT CONDUCTION PATHS BELONGING TO THE AUTONOMIC NERVOUS 



SYSTEM 



Thanks to the work of Langley, we know that the conduction pathways in 

 the sympathetic nervous system are at least as sharply defined as those in the 

 brain and spinal cord. A great deal has already been done in the way of tracing 

 these pathways; and some of the more important of these are given in the out- 

 line which follows: 



1. Paths for the efferent innervation of the eye (Figs. 247, 250): 



(a) Ocular craniosacral pathway. 



Preganglionic neurons: Cells in the Edinger-Westphal nucleus, 

 fibers by way of the third cranial nerve to end in the ciliary ganglion. 



Postganglionic neurons: Cells in the ciliary ganglion, fibers by 

 way of the short ciliary nerves to the ciliary muscle and the circular 

 fibers of the iris. 



Function: Accommodation and contraction of the pupil. 



(b) Ocular thoracicolumbar pathway. 



Preganglionic neurons: Cells in the intermediolateral column of 

 the spinal cord, fibers by way of the upper white rami and sympathetic 

 trunk to end in the superior cervical ganglion. 



Postganglionic neurons: Cells in the superior cervical ganglion, 

 fibers by way of the internal carotid plexus to the ophthalmic division 

 of the fifth nerve, the nasociliary and long ciliary nerves of the eyeball; 

 other fibers pass from the internal carotid plexus through the ciliary 

 ganglion, without interruption, into the short ciliary nerves and to 

 the eyeball. 



Function: Dilatation of the pupil by the radial muscle-fibers of 

 the iris. 



2. Paths for the efferent innervation of the submaxillary gland (Fig. 250) : 

 (a) Submaxillary craniosacral pathway. 



Preganglionic neurons: Cells in the nucleus salivatorius superior, 

 fibers by way of the seventh cranial nerve, chorda tympani, and 



