Mecanoreceptores da mucosa palatina de avestruz (Struthio camelus): estudo ao microscópio de luz

Abstract

Foram estudados corpúsculos de Herbst da mucosa palatina de avestruz em nível de microscopia de luz. Os corpúsculos compõem-se de uma cápsula externa, cápsula interna e axônio central. A cápsula externa apresentou numerosas lamelas, enquanto que a cápsula interna mostrou estrutura de folhas compactas. Os corpúsculos apresentaram formato ovalado ou circular e circundado por espessos feixes de fibras colágenas. Cada lamela estava composta de uma densa rede de fibras espessas. Os axônios terminais estavam situados ao longo do eixo, terminando em um bulbo terminal. As fibras da cápsula externa, coradas por Picrosirius e examinadas no microscópio óptico sob luz polarizada, revelou a presença de fibras colágenas do tipo I em verde e na região periférica observou-se grande quantidade de fibras colágenas do tipo III. Os corpúsculos apresentaram-se envoltos por células planas e envoltos por fibras colágenas.

Morphological Features of Herbst Corpuscles in the Oropharynx of the Ostrich (Struthio camelus) and Emu (Dromaius novaehollandiae)

“…This differs from the Herbst corpuscles depicted in the bill tip organ in the kiwi (Cunningham et al, ) and in other birds (Bolze, ; Cobb and Bennett, ; Watanabe et al, ; Toyoshima et al, ; Halata and Grim, ) where the outer zone is relatively narrow and the inner core forms a considerable component of the corpuscle. This feature of a larger outer zone and smaller inner core was briefly noted by Guimarães et al () when comparing the Herbst corpuscles in the ostrich palate to those in the chicken. As in the capsule of the ostrich, a fibroblast displaying a sensory cilium was identified in the outer zone, a phenomenon not previously reported in avian Herbst corpuscles.…”

“…Based on these studies, the Herbst corpuscles of neognaths demonstrate the following general structural features: a central axon surrounded by an inner core formed by specialized Schwann cells, an outer zone which contains collagen fibers and surrounds the lamellated inner core, and an outer capsule derived from the perineurium (Gottschaldt, ; Malinovský and Páč, ). The basic structure of Herbst corpuscles in the oropharynx of ratites has been briefly described by light microscopy in the ostrich ( Struthio camelus ) (Palmieri et al, ; Tivane et al, ; Guimarães et al, ; Tivane, ), emu ( Dromaius novaehollandiae ) (Crole, ; Crole and Soley, ), and greater rhea ( Rhea americana ) (Feder, ) as well as in the bill of the kiwi ( Apteryx spp.) (Cunningham et al, ).…”

“…The brief reports on the structure (Palmieri et al, ; Tivane et al, ; Guimarães et al, ; Tivane, ; Crole, ; Crole and Soley, ; Crole et al, ) of Herbst corpuscles in the oropharynx of the ostrich and emu require further examination to determine whether they share morphological features between the two species and with neognathous birds. This information becomes particularly relevant in view of a recent study demonstrating differences between these two ratites in respect of the comparative distribution of Herbst corpuscles in the oropharynx and the significance of their location (Crole and Soley, ).…”

Histology of Palate and Soft Palate Tonsil of Collared Peccary (Tayassu tajacu)

“…The collared peccary lips (Teófilo et al., ) as well as the palate showed that its oral mucosa is rich in mechanoreceptors. Although Meissner, Paccini and Ruffini types are often associated with the oral mucosa (Halata et al., ; Jayawardena et al., ; Watanabe, ; Guimarães et al., ; Teófilo et al., ), in the present study pacinian corpuscles were the most frequently observed. It is known that the mechanoreceptors are important for the sensorimotor regulation of oral behaviour (Trulsson and Johansson, ).…”

Comparative Distribution and Arrangement of Herbst Corpuscles in the Oropharynx of the Ostrich (Struthio camelus) and Emu (Dromaius novaehollandiae)

“…Palmieri et al () and Tivane et al () noted a particular concentration of Herbst corpuscles in the median palatine ridge of the nonglandular region in the oropharyngeal roof of the ostrich. Guimarães et al () reported on the presence of Herbst corpuscles in the caudal third of the ostrich oropharyngeal roof. However, as revealed by other studies in this species (Tivane et al, ; Tivane, ; Crole and Soley, ), the distribution of these structures is far more widespread.…”