Morfometria do coração e dos vasos da base e sua implicação no mergulho em Chelonia mydas

Abstract

Pesq. Vet. Bras. 33(Supl.1):32-38, dezembro 2013 32 RESUMO.-Objetivou-se caracterizar a morfologia das câ-maras cardíacas e das artérias aortas e pulmonares da espécie Chelonia mydas. Foram avaliados 11 espécimes de C. mydas mortas coletadas no litoral do estado do Rio Grande do Norte, Brasil. Os animais foram necropsiados para a obtenção do coração, fragmentos das artérias aorta e pulmonares direita e esquerda. Os vasos adquiridos foram fixados em formol e submetidos ao processamento histológico de rotina e coloração com Técnica de Verhoff modificada.Enquanto, do coração, os parâmetros largura, altura base--ápice e a circunferência ventricular foram mensurados por meio do paquímetro. Nessa espécie a microscopia das arté-rias pulmonares e artérias aortas variaram de acordo com o antímero. A maior espessura relativa do Cavum Venosum (CV) auxilia no bombeamento cardíaco durante o mergulho e sua menor espessura direita é uma vantagem para a dilatação ventricular durante a imersão profunda enquanto que a quantificação das lâminas elásticas e fibras musculares da túnica média das artérias aortas e pulmonares direita e esquerda comprovaram que a túnica média das aortas predomina o componente elástico vs. muscular, entretanto, nas artérias pulmonares o componente elástico não-predomina. Essa angioarquitetura pode estar relacionada com a capacidade de mergulho, favorecendo um maior aproveitamento do sangue oxigenado armazenado previamente durante o período de apneia. This study aimed to characterize the morphology of the heart chambers, pulmonary arteries and aortas of Chelonia mydas. Eleven specimens were evaluated from dead C. mydas collected on the coast of the state of Rio Grande do Norte, Brazil. The animals were necropsied to obtain heart, aorta and fragments of the right and left pulmonary vessels. The vessels were fixed in formalin and subjected to histological processing and staining by a modified Verhoff technique. The parameters width, height and base-apex ventricular circumference of the heart were measured with a caliper. In the species the microscopy of pulmonary arteries and aorta varied according to the antimere. The largest relative thickness of Cavum venosum (CV) assists the cardiac output during diving, and its smaller thickness is advantageous for the right ventricular dilation during deep immersion, while the quantification of elastic and muscle fibers of the tunica media of aortas and right and left pulmonary arteries showed that the medial layer of aorta dominates the elastic vs. muscle fibers; however the elastic fibers are not dominating in the pulmonary arteries. The angioarchitecture may be related to the ability to swim, favoring better use of oxygenated blood previously stored during the period of apnea.

Staining of elastic and muscle fibers to morphometric studies in Chelonia mydas

“…Both the arteries and veins are composed of smooth muscle fibers and elastic fibers, being of great relevance for the distinction of blood vessels by its prevalence in the adventitia and medium tunica (MENDES FILHO and BRITO, 2000). The histomorphological study of the arteries may be related to the ontogeny and behavior of the species (BRAZ, QUEIROZ, OLIVEIRA et al, 2012).…”

Histology and Immunohistochemistry of the Cardiac Ventricular Structure in the Green Turtle(Chelonia mydas)

“…In crocodilians, the thick left chamber could be a justification for greater resistance to maintain stroke volume from increasing blood pressure (Franklin and Axelsson, ). However, this difference has a smaller relation between the Cavum venosum and Cavum arteriosum , indicating the smaller thickening relative to the Cavum venosum wall, which in turn is largely responsible for pumping blood to the lungs in this species (Braz et al., ). In birds, thickness of the compact layer of the left ventricle is five times thicker than in mammals, an adaptation that permits greater delivery of blood propulsion to the muscles during flight (Sedmera et al., ).…”