PHYSIOLOGY OF NERVE TISSUE. 



73 



nerve is invested by a thick layer of lamellated connective tissue, 

 known as the epineurium. A transverse section of a nerve shows 

 (see Fig. 8) that it is made up of a number of small bundles of fibers, 

 each of which possesses a separate investment of connective tissue 

 the perineurium. Within this membrane the nerve-fibers are sup- 

 ported by a fine stroma the cndoneurium. After pursuing a longer 

 or shorter course, the nerve trunk gives off branches, which interlace 

 very freely with neighboring branches, forming plexuses, the fibers 

 of which are distributed to associated organs and regions of the 



FIG. 8. TRANSVERSE SECTION OF A NERVE (MEDIAN). 

 ep. Epineurium. pe. Perineurium. ed. Endoneurium. 



body. From their origin to their termination, however, nerve- 

 fibers retain their individuality, and never become blended with ad- 

 joining fibers. 



As nerves pass from their origin to their peripheral terminations, 

 they give off a number of branches, each of which becomes invested 

 with a lamellated sheath an offshoot from that investing the parent 

 trunk. This division of nerve bundles and sheath continues through- 

 out all the branches down to the ultimate nerve-fibers, each of which 



