NERVOUS TISSUE 



161 





branches which end in enlarged terminal networks between and upon the 

 tactile cells. These corpuscles are found in some of the papillae, or con- 

 nective tissue elevations just beneath the epidermis, being especially 

 numerous in those of the soles and palms (23 in i sq. mm.) and in the 

 finger tips; they occur also "in the nipple, border of the eyelids, lips, 

 glans penis and clitoris." 



Genital corpuscles are large, round 

 or oval bodies 60-400 n long (Fig. 153) 

 which may receive as many as ten 

 nerve fibers. These ramify and send 

 branches to neighboring corpuscles, 

 and also to the epidermis. The gen- 

 ital corpuscles are deeply placed be- FlG - 

 neath the epithelium of the glans 

 penis, clitoris, and adjoining structures. 



Bulbous corpuscles (of Krause) are smaller than the genital corpuscles, 

 having a diameter of 20-100 n (Fig. 154). They are most numerous 

 (1-4 in a sq. mm.) in the superficial connective tissue of the glans penis 

 and clitoris. Similar structures, either round or oval, are found in the 

 conjunctiva and "edge of the cornea, in the lips and lining of the oral 

 cavity, and probably in other parts of the corium." They have thinner 



capsules and receive fewer nerves than 

 the genital corpuscles, which they re- 

 semble. The articular corpuscles, found 

 near the joints, belong in the same 

 category. 



Cylindrical corpuscles (cylindrical 

 end bulbs of Krause) contain a single 

 axial nerve fiber with few or no branches, 

 terminating in a knob-like or rounded 

 extremity (Fig. 155). The fiber is sur- 

 rounded by a semi-fluid substance, 

 sometimes described as an inner bulb, 

 and this is enclosed in a few concentric 

 layers of cells which are continuous 

 with the sheath of the nerve. Cylin- 

 drical corpuscles are found in the 

 mucous membrane of the mouth and in the connective tissue of muscles 

 and tendons. 



Lamellar corpuscles (or Pacinian corpuscles) are macroscopic elliptical 

 structures 0.5-4.5 mm. long and 1-2 mm. wide (Fig. 156). They were 

 first observed in dissections, as minute vesicular bodies attached to the 

 terminal branches of nerves. Microscopically they are striking objects ; 



Axis cylinder. 



Inner core. 



FIG. 156. SMALL LAMELLAR CORPUSCLE 



FROM THE MESENTERY OF A CAT. X so. 

 The nuclei of the capsule cells appear as 

 thickenings. The myelin of the nerve 

 fiber may be traced to the inner core. 



