Morphological study of larynx, trachea, and lungs of Didelphis marsupialis (LINNAEUS, 1758)

• Published in: Veterinary World Vol. 13; no. 10; pp. 2142 - 2149
• Main Authors: Pantoja, Bruna Tassia Santos, Silva, Armando Reinaldo Marques, Mondego-Oliveira, Renata, Silva, Thamires Santos, Marques, Babara Carvalho, Albuquerque, Rafaela Pontes, Sousa, Joicy Cortez Sá, Rici, Rose Eli Grassi, Miglino, Maria Angélica, Sousa, Alana Lislea, Franciolli, André Luís Resende, Sousa, Eduardo Martins, Abreu-Silva, Ana Lúcia, Carvalho, Rafael Cardoso
• Format: Journal Article
• Language: English
• Published: India Veterinary World 01.10.2020
• Subjects: Anatomy; Arteries; Biometrics; Blood vessels; Bronchus; Cartilage; Chondrocytes; Comparative analysis; Didelphis marsupialis; Epiglottis; Epithelium; Formaldehyde; Histology; Larynx; Lungs; marsupials; Morphology; Ontogeny; Paraffin; Perichondrium; Pharynx; Phylogeny; Physiological aspects; Respiratory system; Respiratory tract; Serous glands; Skull; Smooth muscle; Thorax; Thyroid; Thyroid gland; Brazil; histology; anatomy; marsupials; respiratory tract
• ISSN: 0972-8988; 2231-0916
• DOI: 10.14202/vetworld.2020.2142-2149

From a biomedical point of view, the value of marsupials as a model of primitive mammals is indisputable. Among its species, the possum is a model that allows the study of the ontogeny of different organic systems, as well as their physiological aspects. The relevance of anatomical, functional, evolutionary, and phylogenetic study of marsupials for the development of comparative morphology is extensively documented in the literature. However, there are still many aspects to be further evaluated, as the anatomy and histology of the respiratory tract of this species. The aim of this study was to describe the morphology of the larynx, trachea, and lungs of . Five adult male animals were donated to the Comparative Animal Anatomy Laboratory - LAAC/CCAA-UFMA, for morphological studies. Specimens were washed in running water to perform biometrics. Then, they were fixed with 10% formaldehyde solution. After the fixation period, the specimens were positioned in dorsal decubitus position, for dissection of the respiratory system organs, by opening the ventral region of the neck and thoracic cavity, with subsequent removal of the pectoral muscles, ribs, and sternum. For histological analysis, fragments of 1 cm of the larynx (epiglottis and thyroid cartilages), trachea, and lungs were collected and fixed in 10% formaldehyde solution. Right after fixation, the fragments were dehydrated in increasing concentrations of ethyl alcohol (70, 80, 95, and 100%), diaphanized in xylene, embedded in paraffin, and sectioned into thin slices of 5 μm using a microtome. Sections were stained using the hematoxylin and eosin technique. Anatomically, the larynx starts right after the pharynx. It consisted of four cartilages: Epiglottis, cricoid, thyroid, and arytenoid. The trachea was made of dorsally incomplete cartilaginous rings. At the entrance of the thoracic cavity, it bifurcated into the left and right main bronchus. The left lung was smaller than the right lung, with two lobes (cranial and caudal). The right lung presents the cranial, middle, caudal, and accessory lobes. Histologically, the epiglottis consisted of elastic cartilage and is covered by a non-keratinized stratified squamous epithelium. Thyroid cartilage is made of hyaline cartilage covered by smooth muscle. The trachea presents hyaline cartilage, with ciliated pseudo-stratified epithelium, serous glands, isogenic groups of chondrocytes, and perichondrium. The lung consisted of bronchi, bronchioles, and alveoli, also presenting blood vessels and arteries. Morphologically, the larynx, trachea, and lungs of were similar to those of the other described in the literature.