528 A MANUAL OF VETERINARY PHYSIOLOGY 



The bloodvessels, glands, and walls of the abdominal and 

 pelvic viscera ar^ provided with constrictor, secretor, and 

 viscero-motor fibres through fibres from the spinal cord, which 

 pass through the vertebral system of ganglia until they reach 

 the prevertebral, or even the terminal, before they find their 

 cell-station, from which they issue as grey post-ganglionic fibres. 



From the sacral cord the pre-ganglionic fibres emerge with 

 the second to the fourth sacral nerves, pass through but do not 

 connect with the vertebral ganglia, but have their cell-stations 

 either in the prevertebral ganglia, hypogastric plexus, or in 

 terminal ganglia in the walls of the viscera. The sacral sym- 



SPINAL CORD 



PREVERTEBRAL 

 GANGLIA 



POST-GANG LIOI 

 FIBRE 



Fig. 157. — Diagram of the Autonomic Ganglia. 



The pre-ganglionic fibres issue from the spinal cord, and in the upper figure are 

 shown as passing through, but forming no cell connection with the lateral 

 (vertebral) ganglion. As a pre-ganglionic fibre it continues, and makes a 

 cell connection in the next, or pre- vertebral ganglion, from which the post- 

 ganglionic fibres issue. 



In the lower figure some of the pre-ganglionic fibres have formed a cell connection 

 with the lateral ganglion, and issue as post-ganglionic fibres. Others pass 

 through, still as pre-ganglionic, and some of these form cell connections in the 

 pre-vertebral ganglion ; others do not, and, continuing as pre-ganglionic 

 fibres, reach the terminal ganglion, where they arborise ; from this post- 

 ganglionic fibres issue. 



pathetic supplies the bloodvessels of the generative organs and 

 rectum with dilator nerves, and the walls of a part of the large 

 intestine and rectum, uterus, bladder, and retractor penis with 

 motor, and, to some of the organs, inhibitory fibres. 



The sympathetic system furnishes impulses of a very opposite 

 nature to the different tissues : for instance, to the bloodvessels, 

 constrictor mainly, but also dilator impulses ; to the muscle 

 of the viscera, accelerator and inhibitory impulses. The same 

 branch of nerve, though not the same fibre, may be motor for one 

 organ or tissue, inhibitory for another, constrictor for a blood- 

 vessel, and inhibitory for visceral muscle. All accelerator and 

 inhibitory nerves may be regarded as functioning in the same 



