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

Abstract

Background and Aim: 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 Didelphis marsupialis. Materials and Methods: 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 cm2 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. Results: 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. Conclusion: Morphologically, the larynx, trachea, and lungs of D. marsupialis were similar to those of the other Didelphids described in the literature.

Gross and histological study of the larynx in red sokoto goat (Capra hircus) from Sokoto, Nigeria

“…This is also found in sheep and goat by ALSadi (2006) to be of elastic type. This at same time goes in line with the findings in opossums (Pantoja et al, 2020) that epiglottis consisted of elastic cartilage and is covered by a non-keratinized stratified squamous epithelium. CONCLUSION: This research work focus on evaluating the gross and microscopic anatomy of the larynx, thus, providing information for future use in both anatomical studies and clinical applications.…”

“…This finding is in accordance with that of sheep and goat (ALSadi, 2006) also as that of giraffe (Erdogan and Pérez, 2017) but differs with that of Paca (Ruaro et al, 2021) as it was found to be round. The histology of the thyroid, arytenoids, and cricoid shows hyaline cartilage as that of sheep (ALSadi, 2006) and Didelphis marsupialis (L) (Pantoja et al, 2020). The photomicrograph of the epiglottis in red Sokoto goat shows an elastic cartilage with dense elastic fibers in the matrix.…”

Morphological Features and Morphometric Parameters of the Lungs of Sexually Mature Horses (Equus Ferus Caballus L., 1758)

“…Some scientists [20] consider the manifestation of lung asymmetry in domestic mammals to be a genetic trait. Others argue [21] that the asymmetry is associated with an asymmetric position of the heart and other organs in the chest cavity, depending on the intensity of their gas exchange function, which manifested itself during the evolutionary development of animals. The most pronounced asymmetry of all mammals is inherent in small rodents (rat, guinea pig, hamster), in which the left lung is not divided into lobes, and the right lung has four lobes [22].…”

“…At the same time, the study of the lungs of various animal species showed the presence of individual morphological features in the lobular structure of the lungs [21]. Thus, in bats, the left lung is not divided into lobes, and in mink and sable, the left lung is divided into only two lobes -cranial and caudal [6].…”

The common black-eared opossum in the symbolic and iconographic universe. From the effigy ornaments in the lesser Antilles to the European graphics of Simivulpa and its variants in the 16th – 17th centuries

“…From biology (Rueda, Ramírez & Osorio, 2013) and ecology (Hunsaker II, 1977), an exhaustive revision of the behavior and ecological strategies of the marsupials in the New World has been presented, based on demographic data, reproductive biology (Harder, 1992), longevity, anatomy and histology (Santos Pantoja et al, 2020), morphometric differences between subspecies (Cerqueira y Lemos, 2000), including environmental relations and threats from overexploitation of wildlife and excessive hunting, not forgetting the impact of urban and rural growth (Adler, Carvajal, David-Foust & Dittel, 2012;Vaughan & Hawkins, 1999), or disturbing events such as fires and floods, which have put the endemic fauna at risk and have led to the creation of rehabilitation centers in order to protect them (Tardieu, Rollock & García, 2020).…”