154 VETERINARY PHYSIOLOGY 



gland, and sweat glands. The course of these fibres is of 

 importance in medicine, since tumours in the upper part of 

 the thorax may press upon them. 



(2) Thorax. The fibres to the thoracic organs also come 

 off in the upper dorsal nerves, have their cell stations in the 

 stellate ganglion, and pass to the heart and lungs. 



(3) Abdomen. These fibres come off in the lower dorsal 

 and upper lumbar nerves. They course through the lateral 

 ganglia and form synapses in the collateral ganglia of the 

 abdomen the solar plexus and the superior and inferior 

 mesenteric ganglia. From these they are distributed to the 

 abdominal organs, being vaso-constrictor to the vessels, in- 

 hibitory to the muscles of the stomach and intestine, and 

 possibly secretory to the pancreas. 



(4) Pelvis. The fibres for the pelvis leave the cord by the 

 lower dorsal and upper lumbar nerves, and have their cell 

 stations in the inferior mesenteric ganglia, from which they 

 run in the hypogastric nerves to the pelvic ganglia. They 

 are vaso-constrictor, inhibitory to the colon, and motor to the 

 bladder, uterus and vagina and the retractor penis. 



(5) Fore Limb. These fibres, coming out by the upper and mid 

 dorsal nerves, have their synapses in the sympathetic ganglia 

 of the sympathetic chain, and passing back into the spinal 

 nerves by the grey rami, course to the blood vessels, hairs, and 

 sweat glands of the limb. 



(6) Hind Limb. The fibres take origin from the lower dorsal 

 and upper lumbar nerves, have their cell stations in the lateral 

 ganglia, and pass to the leg in the same way as do the fibres 

 to the arm. 



B. The Cranial and Sacral Fibres. These pass out from the 

 upper and lower ends of the cord, and they do not pass through 

 the lateral ganglia but have their cell station in some of the 

 collateral ganglia. 



(1) The third cranial nerve carries fibres which have their 

 synapses in the ciliary ganglion, and pass on to the sphincter 

 pupillae and ciliary muscle. 



(2) The seventh nerve carries fibres through the chorda 

 tympani to cell stations in the submaxillary and sublingual 

 ganglia. These are secretory to the submaxillary and sub- 

 lingual glands. 



