VI 



SYMPATHETIC SYSTEM 



365 



Mid-brain 

 autonomic 



Bulbar 

 autonomic 



Sacral 



autonomic 



Effects of stimulating the mid-brain, 

 bulbar and sacral autonomic fibres. 



Contraction of iris 

 Contraction of ciliary muscle 



Inhibition of heart, and of 

 vessels of mucous membranes 

 of head 



Motor and inhibitory effects on 

 smooth musculature of gut 

 from oesophagus to descend- 

 ing colon 



Motor and inhibitory effects on 

 muscles of trachea and lungs 



? Secretion of gastric glands, 

 liver, and pancreas 



Inhibition of arteries of rectum, 

 anus, and external generative 

 organs 



Contraction of smooth muscula- 

 ture of descending colon, 

 rectum, and anus 



Inhibition of smooth muscles of 

 anus 



Contraction of bladder 



Inhibition (? contraction) of 

 urethra 



Inhibition of muscles of external 

 generative organs 



Effects of stimulating the sym- 

 pathetic nerves. 



Contraction of dilator of iris 

 Contraction of unstriated orbital 



muscle 

 Contraction of arteries of eye 



Acceleration of heart and con- 

 traction of blood-vessels in 

 mucous membranes of head 



Inhibitory and motor effects on 

 smooth musculature of gut 

 from oesophagus to descend- 

 ing colon 



? Secretion of gastric glands, 

 liver and pancreas 



Contraction of vessels of gut 

 from oesophagus to descend- 

 ing colon 



? Contraction of vessels of lung 



Contraction of vessels of abdom- 

 inal viscera 



Contraction of musculature of 

 spleen, ureters and internal 

 generative organs 



Contraction of smooth muscles, 

 and arteries of skin 



Secretion of cutaneous glands 



Contraction of arteries of rectum, 

 anus, and external generative 

 organs 



Inhibition and contraction of 

 smooth musculature of de- 

 scending colon, rectum, and 

 anus 



Inhibition and contraction of 

 bladder 



Contraction (? inhibition) of 

 urethra 



Contraction of muscles of 

 external generative organs 



is through the rarni communicantes. We have seen (p. 292, et seq.) 

 that the Bell-Magendie law holds good for the sympathetic fibres, 

 except that the vaso-dilator fibres to the fore- and hind-limbs, in 

 the dog at least, leave the cord by dorsal and not by ventral roots. 

 The remaining efferent fibres of the sympathetic system run in 

 the ventral roots, and beyond the spinal ganglia join the fibres 

 of the dorsal roots, with which they run for a short course, 

 forming the so-called spinal nerves. These give off branches at 

 different intervals, including the rami communicantes, first, the 

 white, later or more peripherally the grey rami. In some cases, 

 however, the white and grey rami arise at approximately the 

 same point of the spinal nerve, and unite in a common trunk. 



