THE SYMPATHETIC NERVE SYSTEM 383 



THE SYMPATHETIC NERVE SYSTEM 



The sympathetic system consists of numbers of 

 ganglia connected with one another by extension of 

 their nerve trunks. It is not an independent system 

 for the conveyance of nerve impulses, but is in rela- 

 tion with the cerebrospinal system of nerves through 

 communicating branches. 



The ganglia are classified - as central ganglia which 

 are arranged on either side of the spinal column, and 

 are connected to each other by nerve trunks, forming 

 the gangliated cord. The central ganglia extend from 

 the base of the skull to the coccyx, and communicate 

 with the spinal nerves by means of nerves called rami 

 communic antes. 



The ganglia of the cord are classified for purpose 

 of study into the following groups: 



Cervical portion 3 pairs of ganglia. 



Thoracic portion . . . . 10 to 12 pairs of ganglia. 



Lumbar portion 4 pairs of ganglia. 



Sacral portion 4 or 5 pairs of ganglia. 



The ganglia of the sympathetic system are further 

 arranged into minute plexuses called the three great 

 gangliated plexuses. They are situated in the thoracic 

 and abdominal cavities and receive interconnecting 

 nerve trunks which form the following plexuses: (1) 

 The cardiac, which receives nerve trunks from the 

 upper three cervical ganglia, and gives off peripheral 

 branches to the heart, lungs; (2) the solar or celiac 

 plexus, which receives nerve trunks (splanchnic nerves) 

 from the thoracic portion and gives off terminal 

 branches which form underlying plexuses and inner- 

 vate the muscles of the intestinal wall, and other 

 organs of the abdominal cavity, bloodvessels, and 

 secreting cells of glands; (3) the hypogastric plexus, 

 which receives branches from the lumbar and sacral 



