[New observations on the structure of the lingual filiform papillae epithelium of the toad Bufo marinus L.: Light and transmission electron microscopy study].
There are several inconsistencies and confusions about the microscopic structure in the anurans dorsal, non-sensory, mucosal epithelium of the tongue. The aim of this work was to differentiate the structure of the epithelium covering filiform papillae from the glandular epithelium. For this, samples of the dorsal distal mucosa of Bufo marinus tongue were processed for light microscopy (LM) and transmission electron microscopy (TEM). For LM, stained 1 micron sections were used. The results showed that the filiform papillae were covered by a biestratified epithelium formed by a basal layer of dendritic cells and an upper surface layer consisting of numerous seromucous secretory cells, dendritic cells apical processes, and some goblet cell-like and ciliated cells. LM revealed that most filiform papillae showed the seromucous secretory cells in apparent resting state. These cells were characterized by a basal, round nucleus, pale cytoplasm with small, dispersed, stained granules in the supranuclear region. With TEM, seromucous secretory cells exhibited poorly developed RER, scattered medium electron dense secretory granules and microridges at the apical surface. Dendritic cells were seen as branched cells completely surrounding the basolateral surfaces of secretory cells. In addition, some dendritic cell processes have microvilli at their abutting endings. Goblet cell-like cells theca showed a continuous mesh of medium electron dense, partially fused, mucous granules and irregular microvilli-like processes at the apical end. Ciliated cells were mostly localized at the lateral wall of filiform papillae. Results suggest that at the filiform papillae, yuxtacrine or paracrine interactions mediated by physical contacts between dendritic and secretory cells may exist.
González-Elorriaga
M
M
Centro de Microscopía Electrónica, Facultad de Ciencias, UCV, Apartado 47140 Caracas, 1041 A, Venezuela.
D000818:Animals; D002024:Bufo marinus; D004848:Epithelium / Q000648:ultrastructure; D008854:Microscopy, Electron; D009092:Mucous Membrane / Q000648:ultrastructure; D014059:Tongue / Q000648:ultrastructure*
Nuevas observaciones en la estructura del epitelio de las papilas filiformes de la lengua del sapo Bufo marinus L.: estudio con microscopia de luz y electrónica de transmisión.