74 CELL DIFFERENTIATION AND THE ELEMENTARY TISSUES 



Nerve Terminations. 



Nerve fibers terminate peripherally in four different ways: i, by the ter- 

 minal subdivisions which pass in between epithelial cells, and are known as 

 interepithelial arborizations; 2, by motor- plates which lie in the muscles; 

 3, by special end-organs, connected with the sense of sight, hearing, smell, 

 and taste; and, 4, by various forms of tactile corpuscles. 



FIG. 98. Sensory Nerve Terminations in Stratified Pavement Epithelium. Golgi's rapid 

 method. (After G. Retzius.) 



The Interepithelial Arborizations. This forms a most common 

 mode of termination of the sensory nerves of the body. The nerve fibers 

 to the surface of the skin or mucous membrane lose their neurilemmse and 

 myelin sheaths, the bare axis-cylinder divides and subdivides into minute 

 ramifications among the epithelial cells of the skin and mucous membrane. 

 In the various glands of the body this form of termination also prevails. 

 The hair bulbs, the teeth, and the tendons of the body are supplied by this 

 same process of terminal arborization, figures 98, 99. 



FIG. 99. Sensory Nerve Termination in the Epithelium of the Mucosa of the Inferior 

 Vocal Cord and in the Ciliated Epithelium of the Subglottic Region of the Larynx of a 

 Cat Four Weeks Old. (After G. Retzius.) Golgi's rapid method. , Nerve fibers rising 

 from the connective-tissue layer into the epithelial layer, where they terminate in ramified 

 and free arborizations. 



The motor nerves to the muscles end in what are known as muscle plates, 

 the details of whose structure have been already described. 



The special sensory end-organs will be described later in the chapter 

 on the Special Senses. 



A fourth form of termination consists of corpuscles that are more or less 

 encapsulated, and these are known as the corpuscles of Pacini, the tactile 



