NERVE EXDIXGS IN EPITHELIUM 



125 



broad base rests upon the basement membrane, their narrower 

 apex extends nearly to the surface of the epithelium. The apex 

 of the bud is thus covered by the superficial squamous epithelial 

 cells except for a narrow tubular opening which overlies the su- 

 perficial pole of the end organ. This canal presents an external 

 and an internal ostium, respectively designated the outer and 

 inner taste pore. The inner taste pore leads into a goblet-shaped 

 depression in the apex of 

 the taste bud, into which 

 the cuticular processes of 

 the gustatory cells pro- 

 ject (von Ebner *). 



The taste buds con- 

 sist essentially of two 

 varieties of cells, the gus- 

 tatory and the susten- 

 tacular. The latter in- 

 clude the broad outer 

 sustentacular or tegmen- 

 tal cells at the surface 

 of the bud, the inner 

 sustentacular cells with- 

 in, and the basal cells 

 which lie near the base- 

 ment membrane. 



The gustatory cells 

 are slender neuro-epithe- 



lial structures whose nucleus causes a fusiform enlargement near 

 their center or toward the basal end. Their cytoplasm is finely 

 granular; their nucleus stains deeply and is ovoid or rod-shaped. 

 The distal end of the " cell carries a delicate, highly refractive 

 cuticular process which projects beyond the apices of the susten- 

 tacular cells and as far as the inner taste pore. Their proximal 

 end is often bifid, forked, or so flattened as to form a foot-like 

 extremity which is connected with the basal cells by fine processes. 



The outer and inner sustentacular cells are elongated epithe- 

 lioid cells, having an ovoid or spheroidal vesicular nucleus which 

 causes no bulging of the protoplasm, and a coarsely reticular and 

 frequently vacuolated cytoplasm. The distal ends of the cells 



Cone. 



*- Supporting cell. 



Neuro-epithelial 

 cell. 



. Rod cell. 



Nerve fibrils. 



FIG. 120. SCHEMATIC REPRESENTATION OF A 



TASTE BCD. 

 (After Hermann, from Bohm and von Davidoff.) 



* Kiilliker's Handbuch. 



