title: Light and scanning electron microcopy study of the tongue in Rhea americana.
abstract: Morphological characteristics of the tongue were studied in adult rhea (Rhea americana). The lingual surface and the surface of epithelium-connective tissue interface of rhea tongue were examined macroscopically and by light and scanning electron microscopy. The rhea tongue revealed a triangular aspect, without adjustment of the inferior bill formation, occupying approximately ¼ of the length of the oral cavity. Lingual papilla-like structures were not observed over the lingual surface. The tongue mucosa was composed of a thick non-keratinized stratified squamous epithelium in the dorsal and ventral part, supported by a connective tissue core. The submucosa contained numerous glands with cytoplasmic granules, and luminal secretion was positive for histochemical reaction to Alcian Blue in pH 2.5 and PAS, and negative to Alcian Blue in pH 0.5. Despite the rudimentary characteristic of the tongue in rhea, our results suggest an important role of tongue secretions in food lubrication and humidification during the swallowing process, based on the enormous quantity of lingual glands in the submucosa and the histochemical characteristics of their secretions.
authors.affiliation: Department of Animal Science, State University of Matingá, Av Colombo 5790, Maringá, PR 87020-900, Paraná, Brazil. tcsantos@uem.br
authors.forename: Tatiana
authors.initials: T
authors.lastname: Carlesso Santos
authors.forename: Katia
authors.initials: K
authors.lastname: Yuri Fukuda
authors.forename: Juliana
authors.initials: J
authors.lastname: Plácido Guimarães
authors.forename: Moacir
authors.initials: M
authors.lastname: Franco Oliveira
authors.forename: Maria
authors.initials: M
authors.lastname: Angelica Miglino
authors.forename: Li-Sei
authors.initials: LS
authors.lastname: Watanabe
mesh_terms: D000818:Animals; D008855:Microscopy, Electron, Scanning; D020311:Rheiformes / Q000033:anatomy & histology*; D014059:Tongue / Q000648:ultrastructure*