286 



COORDINATION AND SENSATION 



The side-by-side arrangement of the neurons shows clearly the struc- 

 ture of the ganglia and nerves. The nerve is seen to be a bundle 

 of axons. or nerve fibers, held together by connective tissue, while the 

 ganglion is little more than a cluster of cell-bodies. Their connection 

 is necessarily very close, for the same group of neurons will form, with 

 their axons, the nerve, and, with their cell-bodies, the ganglion (Fig. 

 128). 



End-to-end Connections. These consist of loose end-to- 

 end unions of the fiber branches of certain neurons with 



Muscle 

 cell 



Spinal cord. 



' ' 



Skin 



FIG. 129. Diagram of a nerve path starting at 

 the skin, extending through the spinal cord, and pass- 

 ing out to muscles. A division of this path also 

 reaches the brain. 



the dendrites of other neurons. The pur- 

 pose of such connections is to provide the 

 means of communication between different 

 parts of the body. There appears to be 

 no actual uniting of the fiber branches with the dendrites, 

 but they come into relations sufficiently close to establish 

 conduction pathways, and these extend throughout the body 

 (Fig. 129). They connect all parts of the body with the 

 brain and spinal cord, while connections within the brain 

 and cord bring the parts into communication with each 

 other. 



