TERMINAL FIBRILS. 219 



the nerve-centres (which do not here require further consider- 

 ation), and those situated outside the nerve-centres (somatic). 

 The somatic nerve-terminals of man may be classified thus : 



Efferent: 



Terminal fibrils ; 



Motor end-plates of voluntary muscle. 



Afferent : 



Terminal fibrils ; 



Tactile cells; 



Tactile corpuscles of Wagner (or Meissner) ; 



- Touch, etc. 



End-bulbs of Krause ; 



Corpuscles of Pacini (or Vater) ; 



Taste-terminals ; 



Olfactory terminals; 



Eye; 



Ear. 



Terminal fibrils constitute the simplest form of nerve-end- 

 ings, and are widely distributed, penetrating among the cells 

 of the tissues involved (Fig. 85). They are continuations of 

 the axis-cylinders of the nerve-fibres, which lose their cover- 

 ings and break up into fine naked terminal fibrils. They 

 often exhibit bulbous enlargements at intervals, and end in 

 bulbs or points. They divide and branch, and in some places 

 anastomose to form plexuses. They are either efferent or af- 

 ferent. 



The chief examples of efferent fibrillar nerve-endings are 

 found in involuntary muscle, the heart, and secretory glands. 



Non-striated muscle (as in the intestine and arteries) is usu- 

 ally associated with plexuses (sometimes gangliated) of non- 

 medullated fibres, delicate fibrils from which innervate the 

 muscle-cells. 



The heart-muscle is similarly innervated. 



In many glands, as the salivary, delicate plexuses surround 

 the acini and probably send fibrils (apparently efferent and 

 stimulant to secretion) among the individual epithelium-cells. 



Afferent (sensory) terminal fibrils occur in the epidermis, 



