400 HANDBOOK OF PHYSIOLOGY. 



the cerebro-spinal system, and the unstriped muscles from the sympa- 

 thetic or ganglionic system. 



The nerves terminate in the muscular fibre in the following ways: 

 (1.) In unstriped muscle, the nerves first of all form a plexus, called the 

 ground plexus (Arnold), corresponding to each group of muscle bun- 

 dles; the plexus is made by the anastomosis of the primitive fibrils of 

 the axis-cylinders. From the ground plexus, branches pass of, and 

 again anastomosing, form plexuses which correspond to each muscle 



FI&. 281 Two striped muscle-fibres of the hyoglossus of frog, o, Nerve end-plate; 6, nerve- 

 fibres leaving the end-plate; c, nerve-fibres, terminating after dividing into branches d, a nucleus in 

 which two nerve-fibres anastomose, x 600. (Arndt.) 



bundle intermediary plexuses. From these plexuses branches consist- 

 ing of primitive fibrils pass in between the individual fibres and anasto- 

 mose. These fibrils either send off finer branches, or terminate them- 

 selves in the nuclei of the muscle cells. 



(2.) In striped muscle the nerves end in motorial end-plates, having 

 first formed, as in the case of unstriped fibres, ground and intermediary 

 plexuses. The fibres are, however, medullated, and when a branch of 



