270 



NORMAL HISTOLOGY. 



nervous colls, which constitute the receptive elements of the olfac- 

 tory nervous tract. These are cells with large nuclei and cylin- 

 drical distal bodies, which terminate at the surface of the epithelial 

 layer in several delicate hairs projecting from the surface (Figs. 254 

 and 255). The proximal ends of the cells rapidly taper to a delicate 



Fig. 253. 

 Ba 



rz- 



Iffiift 'Wftiiin 



rin ■»»»«!»» 



i M' 



Bb-JJH£ - 



Bt 



Vertical section through the olfactory mucous membrane of the human nose. (Brunn.) 

 ez, nuclei of the columnar epithelial cells ; rz, nuclei of the nervous or olfactory cells 

 lying among those of the epithelium ; bz, nuclei of basal pyramidal epithelial cells lying 

 among the branching proximal ends of the columnar epithelial cells and tapering ends of 

 the nervous cells; pz, pigmented cell in the layer of lymphadenoid tissues beneath the 

 epithelium; Ba, duct of a gland of Bowman; Bb, dilated subepithelial portion of the 

 duct, receiving several of the tubular acini, Bt. The connection between the duct and 

 tubes is not shown, n, it, branches of the olfactory nerve ; rz*, atypical nervous cell. 



filament, which extends through the subepithelial tissue and becomes 

 associated with others to form the olfactory nerve. The distal ends 

 of the nerve-cells represent the dendrites of neurons, the neurites of 

 which form the axis-cylinders in the olfactory nerve. 



The neurites in the olfactory nerve pass through the cribriform 

 plate of the ethmoid bone to the olfactory bulb of the brain, where 



