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NEUROLOGY 



The peripheral portion of the sympathetic nervous system is characterized by 

 the presence of numerous ganglia and complicated plexuses. These ganglia are 

 connected with the central nervous system by three groups of sympathetic efferent 

 or preganglionic fibers, i. e., the cranial, the thoracolumbar, and the sacral. These 

 outflows of sympathetic fibers are separated by intervals where no connections 

 exist. The cranial and sacral sympathetics are often grouped together owing to 

 the resemblance between the reactions produced by stimulating them and by the 

 effects of certain drugs. Acetyl-choline, for example, when injected intravenously 

 in very small doses, produces the same effect as the stimulation of the cranial or 

 sacral sympathetics, while the introduction of adrenalin produces the same effect 

 as the stimulation of the thoracolumbar sympathetics. Much of our present 

 knowledge of the sympathetic nervous system has been acquired through the appli- 

 cation of various drugs, especially nicotine which paralyzes the connections or 

 synapses between the preganglionic and postganglionic fibers of the sympathetic 

 nerves. When it is injected into the general circulation all such synapses are 

 paralyzed; when it is applied locally on a ganglion only the synapses occurring in 

 that particular ganglion are paralyzed. 



Langley, 1 who has contributed greatly to our knowledge, adopted a terminology 

 somewhat different from that used here and still different from that used by the 

 pharmacologists. This has led to considerable confusion, as shown by the arrange- 

 ment of the terms in the following columns. Gaskell has used the term involuntary 

 nervous svstem. 2 



Gray. 



Sympathetic nervous system. 

 Cranio-sacral sympathetics. 



Oculomotor sympathetics. 



Facial sympathetics. 



Glossopharyngeal sympathetics. 



Vagal sympathetics. 



Sacral sympathetics. 

 Thoracolumbar sympathetics. 



Enteric. 



Langley. 



Autonomic nervous system. 

 Parasympathetics. 

 Tectal autonomies. 



Bulbar autonomies. 



Sacral autonomies. 

 Sympathetic. 



Thoracic autonomic. 

 Enteric. 



Meyer and Gottlieb. 3 



Vegetative nervous system. 

 Autonomic. 



Cranial autonomies. 



Sacral autonomies. 

 Sympathetic. 



Enteric. 



THE CRANIAL SYMPATHETICS. 



The cranial sympathetics include sympathetic efferent fibers in the oculomotor, 

 facial, glossopharyngeal and vagus nerves, as well as sympathetic afferent in the 

 last three nerves. 



The Sympathetic Efferent Fibers of the Oculomotor Nerve probably arise from cells 

 in the anterior part of the oculomotor nucleus which is located in the tegmentum 

 of the mid-brain. These preganglionic fibers run with the third nerve into the orbit 

 and pass to the ciliary* ganglion where they terminate by forming synapses with 

 sympathetic motor neurons whose axons, postganglionic fibers, proceed as the short 

 ciliary nerves to the eyeball. Here they supply motor fibers to the Ciliaris muscle 

 and the Sphincter pupillse muscle. So far as known there are no sympathetic 

 afferent fibers connected with the nerve. 



The Sympathetic Efferent Fibers of the Facial Nerve are supposed to arise from the 

 small cells of the facial nucleus. According to some authors the fibers to the sali- 

 vary glands arise from a special nucleus, the superior salivatory nucleus, consisting 

 of cells scattered in the reticular formation, dorso -medial to the facial nucleus. 

 These preganglionic fibers are distributed partly through the chorda tympani and 



1 Schafer. Textbook of Physiology, 1900. 



2 Gaskell, W. H., The Involuntary Nervous System, London, 1916. 



3 Die Experimentelle Pharmakologie, 1910. 



