166 



PERIPHERAL NERVE TERMINATIONS: END ORGANS 



3. End Bulbs (Krause). These structures (bulbous corpuscles), 

 together with those which follow, form the true so-called encai 



nerve end organs. In the end bulbs the nerve forms a terminal arboriza- 



FIG. 182. GENITAL CORPUSCLES FROM THE CLITORIS OF A RABBIT. 



A single axon from the nerve plexus enters each corpuscle. Methylene blue. 

 Highly magnified. (After Retzius.) 



tion of the varicose and knobbed fibrils which freely anastomose (Dogiel, 

 Ruffini). The bulb is invested with a distinct connective tissue capsule. 

 On entering the bulb the nerve fiber loses its sheaths and the perineu- 

 rium, now represented by Henle's sheath, becomes continuous with the 



B 



-.--.- <v 



FIG. 183. A LAMELLAR CORPUSCLE FROM THE MESENTERY OF A CAT. 

 A, a nearly axial section; B, a transection. Hematein and orange G. X 410. 



capsule of the bulb. Within the capsule the nerve fibrils are embedded 

 in a granular inner bulb. 



The end bulbs vary much in both size and shape. They may be 

 cither spheroidal, ovoid, twisted or convoluted, branched or compound, or 

 cylindroid. They are abundantly found in the conjunctiva, but also 



