FUNCTIONS OF RELATION NERVOUS SYSTEM. 



43 



CHAPTER V. 

 Functions of Relation Nervous System. 



THE functions of relation establish our intercourse 

 with the outside world. They may be classified as 

 functions of sensation and functions of locomotion. 

 Their study is intimately connected with that of the 

 nervous system. 



Nervous tissue is made up of ramified cells, called 

 nerve-cells, and little tubes that contain the ramifica- 



Fia. 23. 



NERVE-CELLS. A, from sympathetic ganglion; B, from cerebrum ; C, from 

 spinal cord ; a. p. axis cylinder process. 



tions of the cells. By their union nerve-cells form a 

 tissue called gray matter on account of its color. Nerve- 

 tubes when united together form white matter. The 

 nerves are made up exclusively of these tubes. 



In certain localities the nervous tissue forms long 

 cords, in others it constitutes masses of varying size and 

 form. The cords are called nerves, and the masses are 

 ganglions or nerve-centres, 



