PAPILLA OF THE TONGUE. 



807 



circular furrow or trench, around which again is an annular elevation of the 

 mucous membrane, covered with the smaller papillae. The exposed surface 

 of the papillae vallatse is beset with numerous smaller papillae or filaments ; 



Fig. 564. 



Fig. 564. VERTICAL SECTION 



OF THE ClRCUMVALLATE 



PAPILLAE (from Kolliker). ^ 



A, the papilla ; B, the sur- 

 rounding wall; a, the epi- 

 thelial covering ; b, the nerves 

 of the papilla and wall spread- 

 ing towards the surface ; c, 

 the secondary papillae. 



and in some of them there 

 is found a central depres- 

 sion, into which mucous follicles open. 



The middle-sized or fungiform papillse, more numerous than the last, are 

 small rounded eminences scattered over the middle and fore part of the 

 dorsum of the tongue ; but they are found in great numbers and closer 



Fig. 565. 



Fig. 565. SURFACE AND SECTION OF THE FUNGI- 

 FORM PAPILLA (from Kolliker after Todd and 

 Bowman). 



A, the surface of a fungiform papilla partially 

 denuded of its epithelium, ^ ; p, secondary 

 papillse ; e, epithelium. 



B, section of a fungiform papilla with the 

 blood-vessels injected, a, artery ; v, vein ; c, 

 capillary loops of simple papillaa in the neigh- 

 bouring structure of the tongue ; d, capillary 

 loops of the secondary papilla? ; e, epithelium., 



together at the apex and upon the bor- 

 ders. They are easily distinguished in 

 the living tongue by their deeper red 

 colour. They are narrow at their point 

 of attachment, but are gradually enlarged 

 towards their free extremities, which are 

 blunt and rounded, and are covered with 

 smaller filamentous appendages or papillae. 

 The smallest papilhe, conical and fili- 

 form, are the most numerous of all. They 

 are minute, conical, tapering, or cylin- 

 drical processes, which are densely packed 

 over the greater part of the dorsum of the 

 tongue, but towards the base gradually 



disappear. They are arranged in lines, which correspond at first with the 

 oblique direction of the two ridges of the papillae vallatae, frit gradually be- 

 come transverse towards the tip of the tongue. At the sides they are longer 

 and more filiform, and arranged in parallel rows, perpendicular to the border 

 of the tongue. 



Considerable variety occurs in the appearance of the papillze on the tongues ot 

 different persons. Thus occasionally instances occur in which the tongue has a 

 quite smooth appearance, and others are seen in which numbers of the filiform papillae 

 are elongated into the appearance of short brown hairs, as shown in Fig. 566. 



