NERVE ENDINGS IN CONNECTIVE TISSUE 



163 



The Fibers. The nerve fibrils of the taste buds are derived from a 

 sub-epithelial plexus which distributes terminal fibrils to the gustatory 

 and sustentacular cells, intragemmal fibers, and to the intervening 

 portions of the stratified epithelium, intergemmal fibers, where they 

 terminate in end fibrils. Von Lenhossek (Anat. Anz., 1892) states that 

 the intragemmal and intergemmal fibers are never derived from the same 

 nerve fiber. Circumgemmal fibers, distributed as varicose fibrils to the 

 surface of the taste bud, may, however, arise from the same nerve fiber 

 as the intragemmal branches. 



Those nerve fibers which enter the taste buds form fine varicose fibrils 

 which are closely applied to, but are not continuous with, the gustatory 

 and the sustentacular cells. The terminal twigs of these fibrils end by 

 minute end knobs which are scarcely distinguishable from the varicosities 

 (Fig. 175). 



NERVE ENDINGS IN CONNECTIVE TISSUE 



The nerve fibers form extensive plexuses in the connective tissues 

 from which terminal branches are distributed to the epithelium (free 

 sensory endings), the walls of the blood and 

 lymphatic vessels (sympathetic vasomotor 

 endings), and to the numerous sensory end 

 organs (encapsulated endings) which occur 

 in abundance in most of the connective tis- 

 sues. Nerves also terminate in connective 

 tissue by free end fibrils some of which, as 

 in the epithelial tissues, possess minute end 

 knobs. Free nerve endings of this nature 

 occur in the tendons, the lungs, the stom- 

 achal and intestinal mucous membranes, 

 the meninges, and in the superficial layer 

 of the corium of the skin and the hair 

 follicles. 



The following types of nerve end organs 

 are found in connective tissue: 



1. Tactile Corpuscles (Touch Cor- 

 puscles of Meisxner). These organs are 

 formed by the terminal expansion of a 

 nerve fiber, which forms a varicose plexus inclosed within a delicate con- 

 pectiye tissue sheath. The nerve fiber, or its primary branches, prior to 



FIG. 177. TACTILE CORPUSCLE 

 OF MEISSNER FROM THE SKIN 

 OF THE HUMAN TOE. 

 Bl, blood-vessel; N, medul- 



lated nerve fiber. Highly 



magnified. (After Schieffer- 



decker.) 



