CHAP. VII.] 



THE NERVOUS SYSTEiVt 



93 



and hence the flow of blood to all parts of the body ; and the 

 respiratory centre which coordinates the actions of the muscles 

 of respiration. 



FIG. 76. DIAGRAM OF NERVOUS SYSTEM, a, a, cortex of cerebral hemispheres ; 

 6, 6, cell-body and dendrones of upper motor neurone, situated in cerebral cortex; 

 6', axone of upper motor neurone, branching at its termination near the dendrones 

 of lower motor neurone ; B, B, cell-body and dendrones of lower motor neurone, situ- 

 ated in the ventral horn of gray matter in the spinal cord ; B', axone of lower motor 

 neurone passing to its termination in a voluntary muscle fibre B" ; C, cell-body and 

 dendrones of upper sensory neurone, situated in the medulla oblongata; C"C", axones 

 of upper sensory neurones, terminating in cortex; c, cell-body of lower sensory neu- 

 rone situated in the dorsal root-ganglion ; c'", dendrone of lower motor neurone, con- 

 ducting impulses from the periphery to the central nervous system; c", long axone 

 of lower sensory neurone, conducting impulses toward the brain; c', short axone of 

 lower sensory neurone, conducting impulses direct to ventral horn. (For the sake of 

 simplicity the connections with the cerebellum are omitted.) 



