N.I 



Postganglionic fibers 



are dotted thus 



Spinal 

 medulla 

 (cord) 



Ram! 



communican- 

 tes going to 

 symp. gang, 

 (preganglionic) 

 Ansa ' \ 

 subclavia- 

 (Annulus of r 



Thoracic -3 

 nerves 



Jugular ganglion (Gang, of the root) 

 Depressor (Fall in pressure or slowing of heart.) 

 (Sensory) separate nerve in rabbit and opossum. 



Nodosum ganglion (Gang, of the trunk) ( Hunf * 

 Inhibitory cranial autonomic fibers 



Superior cervical ganglion 



Descending sympathetic fibers in cord 

 ^Cervical vago- sympathetic trunk 



Harrington) 



^Electrodes (slowing or stoppage of 

 Subclavian heart Augmentation in some 

 art ^ ^<- E\ animals.) 



First thoracic ganglion 

 (Stellate) 



Electro des y 



(Acceleration, or 



augmentation of heart.) 



Fig. 70. Schematic representation of the innervation of the heart of the mammal. The red 

 continuous lines represent the sympathetic (accelerator) preganglionic fibers, and the broken red 

 lines, their postganglionic fibers. The cell stations are in the inferior cervical and stellate ganglia, 

 some extending up to the superior cervical ganglion. The green continuous lines represent the 

 vagus preganglionic fibers, and the broken green lines, their postganglionic fibers. The cell stations 

 in this case are located in the heart itself. It will be observed that electrodes applied to the so- 

 called vagus low down in the neck may stimulate some sympathetic fibers. (From Jackson.) 



