230 



THE ORGANS 



(i) FiliformPapill^ (Fig. iS-i). — These are the most numerous 

 and are distributed over the entire dorsum of the organ. Each 

 consists of a central core of connective tissue containing elastic fibres, 

 which is long and slender, and is covered by stratified squamous 

 epithelium. From the summit of each papilla are given off several 

 secondary papillcB. The epithelium covering the papillae is hornified 

 and often extends from the surface as a long thread-hke projection — 

 hence the.:name, filiform. 



;■•■^^-E 



i^^'^-^^- 







f 



I 





Fig. 135. — Vertical Section through Fungiform Papilla of Human Tongue. XiS- 

 (Szj^monowicz.) a, Secondary papilla; b, epithelium; c, muscle fibres. 



(2) Fungiform Papilla (Fig. 135). — Scattered irregularly over 

 the entire dorsum among the filiform papillae, but fewer in number, 

 are larger papillae of somewhat different structure known as fungi- 

 form papillae. Their summits are rounded instead of pointed and 

 their bases are narrowed. Secondary papillae are given off not only 

 from the summit, but from the sides of the papilla. The epithehal 

 covering is comparatively thin and is not hornified. The connective- 

 tissue cores of these papillae contain but few elastic fibres. 



(3) The Circumvallate Papilla (Fig. 136). — These are fron 

 nine to fifteen in number, and are grouped on the posterior surfaci 

 of the dorsum of the tongue. They resemble the fungiform papillae 

 but are much larger. Each Hes rather deep in the mucous membrane. 



