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

Abstract

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.