Descrição morfológica do sistema respiratório e do coração do jacaré-do-pantanal (Caiman yacare, DAUDIN, 1802) proveniente de zoocriadouro

Abstract

The aim of this work is to describe anatomical and historical aspects of a respiratory system and the heart of the Caiman yacare from a crocodile breeding center. For this purpose, we have chosen and further studied 13 specimens which were perfused and preserved in a 10% formaldehyde solution and they were subjected to the specific anatomical techniques. Both the respiratory system and the heart were separated; their samples were collected and submitted to the specific histological procedures. Macroscopically, there are three laryngeal cartilages, one thyroid and two arytenoids. Trachea consists of a cartilaginous semicircle and the circle rings. It is divided into two main bronchi penetrating into lung bronchi and tracing the secondary branches. Lungs’ lobation is not made of a spongy parenchyma. The heart is four-chambered and besides two atria and two ventricles; there is a structure called arterial cone from which the great vessels of the heart emerge. There were identified two aortas, left and right. The left aorta emerges from the right ventricle and communicates with the systemic trunk through the Foramen of Panizza. From a histological point of view, the conductive parts of the respiratory system are made of ciliated pseudostratified columnar epithelium with mucus-producing cells. The walls of the larynx, trachea and bronchi are formed of a hyaline cartilage. The lung parenchyma is trabecular and highly vascularized. The heart is typically composed of the parts such as epicardium, myocardium and endocardium. According to these observations, it is assumed that the histology of respiratory system and the heart in case of “Jacaré of Pantanal” is similar to other species of reptiles. However, there are some anatomic particulars, which possibly represent the adaptations allowing the perpetuation of the species.