NORMAL HISTOLOGY. 



121 



CHAPTER XVII. 



TONGUE AND TEETH. 

 I. TONGUE. 



The tongue is derived from the epiderm and mesoderm. It con- 

 sists chiefly of a mucous membrane and bundles of muscle fibers as- 

 sociated with connective tissue. It is the organ of taste, this sense 

 being derived especially from the taste-buds which are located in 

 the squamous epithelium which lines its surface. 



OUTLINE OF THE TONGUE. 



Mucous coat. 



f Squamous epithelium. 



Membrana propria. 



Papillae 



Taste buds. 

 [ Furrows and ridges. 



Fibres. . . 



Filiform. 



Fungiform. 



Circumvallate. 



f Branched. 

 1 Striated. 



Muscular tissue 



Adenoid tissue 



Vertical. 



{ Bundles { Transverse. 



Longitudinal. 

 Septum lingualae. 



Interfascicular spaces f Connective tissue. 



containing < Fat. 



I Glands. 

 Reticulum. 



Lymphoid cells. 

 Blood vessels, lymphatics, and nerves. 



The tongue is constituted of a mucous coat, muscular tissue, ade- 

 noid tissue, blood-vessels, lymphatics, and nerves. The mucous coat 

 contains a superficial layer of stratified squamous epithelium. With- 

 in this layer are located the taste-buds, conical bodies which are the 

 seat of the sense of taste and are found upon the fungiform and 

 circumvallate papillae, and in the epithelium of the dorsum and sides 

 of the tongue. Beneath the squamous epithelial layer is the mem* 



