CHAPTER XVI. 



OLFACTORY ORGAN. 



The olfactory region may be divided into the vesti 

 bule, respiratory organ, and the olfactory organ. 



1 . The vestibule is cov- 

 ered with a continuation 

 of the skin, which grad- 

 ually takes on the char- 

 acter of a mucous mem- 

 brane. The epithelium 

 is of a stratified squa- 

 mous variety, and pre- 

 sents hairs, sebaceous 

 glands, and mucous 

 glands. The vestibule 

 comprises the region of 

 the anterior nares. 



2. The respiratory re- 

 gion is lined by ciliated 

 epithelial cells, the nuclei 

 of which are placed at 

 various levels. Hairs 

 and sebaceous glands are 

 absent, but branched al- 

 veolar glands having 

 mucous and serous cells 

 are present. Numerous 



leukocytes are usually found upon the surface. 



453 



Fig. 311. Olfactory mucous 

 membrane; a, sustentacular cells; 

 b, olfactory cells; c, basal cells; d, 

 submucous fibrous tissue; e, glands 

 of Bowman; /, nerve fibers (Leroy). 



