Ultrastructural characteristics of the lung of Melanophryniscus stelzneri stelzneri (Weyenberg, 1875) (Anura, Bufonidae)
The lung of the toad, Melanophryniscus stelzneri stelzneri was studied using scanning and transmission electron microscopy. In M.s.stelzneri the parenchyma forms a polygonal network arrangement, therefore the parenchyma is edicular. These spaces are delimited by the interconnection of third order se...
| Autores: | , , |
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| Formato: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2002 |
| País: | Argentina |
| Recursos: | Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales |
| Repositorio: | Biblioteca Digital (UBA-FCEN) |
| Idioma: | inglés |
| OAI Identifier: | paperaa:paper_03279545_v26_n3_p347_Hermida |
| Acesso em linha: | http://hdl.handle.net/20.500.12110/paper_03279545_v26_n3_p347_Hermida |
| Access Level: | acceso abierto |
| Palavra-chave: | Amphibian Electronic microscopic Lung ultrastructure Respiratory epithelium Toad animal tissue article cell ultrastructure comparative anatomy controlled study female lung alveolus cell type 1 lung alveolus cell type 2 lung parenchyma lung structure male melanophryniscus stelzneri stelzneri nonhuman respiratory epithelium scanning electron microscopy toad transmission electron microscopy Animals Anura Lung Microscopy, Electron Microscopy, Electron, Scanning Amphibia Animalia Bufonidae Melanophryniscus stelzneri Vertebrata |
| Resumo: | The lung of the toad, Melanophryniscus stelzneri stelzneri was studied using scanning and transmission electron microscopy. In M.s.stelzneri the parenchyma forms a polygonal network arrangement, therefore the parenchyma is edicular. These spaces are delimited by the interconnection of third order septa which are covered by respiratory epithelium. Small patches of ciliated epithelium without goblet cells appear irregularly distributed on the septa. The respiratory epithelium consists of one type of pneumocyte, which shows characteristics of both type I and type II alveolar cells of higher vertebrates. The pneumocytes are irregular in shape and possess attenuated cytoplasmic processes, which spread around the capillaries to form the outer layer of the air-blood barrier. These cells contain different types of cytoplasmic bodies: electron dense bodies, multivesicular bodies and lamellar bodies. Dense bodies are probably the precursors of lamellar bodies and the multivesicular bodies are incorporated into the latter. Neuroepithelial bodies appear randomly distributed over the septa. These bodies are separated from the lumen of the lung by thin cytoplasmic processes of neighbouring pneumocytes. The air-blood barrier consists of three layers: epithelium, interstitial space and endothelium. The relatively simple pulmonary structure of M.s.stelzneri is due to a lower degree of partitioning of the pulmonary lumen in comparison to the lung of other bufonid anurans, could be correlated with a well developed cutaneous and buccopharingeal respiration. The testing of this hypothesis awaits further studies. |
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