104 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



sists largely of non-medullated fibers. Terminal 

 branched endings of an axis cylinder, called neuro- 

 podia, have neither medullary sheath nor neurilemma. 

 The axis cylinder, just as it leaves its nerve cell, is 

 likewise uncovered. 



Nerve Trunk. The fibers that constitute a nerve 

 are grouped into bundles called funiculi. Each 

 funiculus is enclosed in a connective- 

 tissue sheath, the perineurium, which 

 sends septa, the endoneurium, in 

 among the individual fibers. The 

 whole nerve is enclosed in a firm con- 

 nective-tissue sheath, the epineurium. 

 Blood- and lymph- vessels accompany 

 the connective-tissue elements and 

 ramify through the nerve just as is 

 the case in a muscle. 



Nerve cells with a long axis cylinder 

 were classified by Golgi as Type I, and 

 with a short axis cylinder as Type II. 

 Golgi believed the former to be motor 

 in function, and the latter sensory, a 

 classification no longer tenable. 



Neuroglia tissue is a delicate sup- 

 porting tissue of the brain and cord, 

 consisting of cells with many fine in- 

 terlacing branches, mossy cells, or spider cells. 

 These cells develop from the ectoderm and are onto- 

 genetically closely related to nerve cells. Their 

 function is to give support, not to conduct nerve 

 impulses. 



The great nerve center in the body is the cerebro- 



Nucle 



Fig. 72. Re- 

 m ak' s fibers 

 (non - medullated 

 fibers) from the 

 pneum ogastric 

 nerve of a rabbit 

 (Bohm and Da- 

 vidoff). 



