FUNCTIONS OP THE SYMPATHETIC SYSTEM 421 



are also located in this organ which is the origin of many 

 of the cranial nerves. 



Functions of the S3nnpathetic system. — This name was 

 originally given to the chain of ganglia extending along 

 each side of the spinal column under the mistaken idea 

 that it was a pathway for all the so-called sympathetic 

 (reflex) actions of distant organs. This system was sup- 

 posed to arise from the brain by branches connected 

 with the fifth and sixth cranial nerves. It is now known 

 that this system consists merely of a collection of ganglia 

 or nerve cells which are connected with one another and 

 with the spinal nerves. While it is customary to limit 

 the term to the ganglia on each side of the spinal column, 

 it actually includes many other ganglia with or without 

 names which lie in different regions of the body. Accord- 

 ing to Professor Langley, the efferent fibers from the 

 sympathetic and related ganglia supply the unstriped 

 muscle tissues, the cardiac muscles and the glands, in short, 

 the muscles of the involuntary organs of the bod}?-, such 

 as the walls of the intestines. He has given the name 

 of autonomic to this system to indicate that these fibers 

 are to a certain extent independent of the central nervous 

 system. All the sjmipathetic ganglia are cormected with 

 the central nervous system by medullated fibers from 

 the spinal or cranial nerves, but these fibers do not pass 

 directly to the imstriped muscle tissue. On the con- 

 trary, they transfer their impulses to a ganglion cell and 

 the impulse passes out through a fiber (autonomic fiber) 

 of this ganglion cell which is usually non-medullated. 



The connection of these fibers with the spinal cord is 

 illustrated in Figure 189. Unlike the fibers which supply 

 the striated muscles, practically the entire set of autonomic 



