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Gas exchange in the tissues and lungs is accurately described by simple equations, and mathematical models of O 2 transport play a paramount role in the conceptual understanding of respiratory physiology. In the present paper, we review an integrative approach to describe maximum oxygen uptake in animals with tidally ventilated lungs. Further, we expand the analysis by including a central...
In the present study, we exposed 53 animals from 23 different species of amphibians and reptiles to microgravity (μg). This nearly doubles the number of amphibians and reptiles observed so far in μg. The animals were flown on a parabolic flight, which provided 20–25s of μg, to better characterize behavioral reactions to abrupt exposure to μg. Highly fossorial limbless caecilians and amphisbaenians...
Animals vary widely in their abilities to tolerate extended periods of food limitation. Although some snakes are known for their unique ability to survive periods of inanition that last up to 2 years, very little is known about the biological mechanisms that allow them to do this. Consequently, the present study examined physiological, compositional, and morphological responses to 168 days of starvation...
The differentiation of the thyroid primordium of reptilian species is poorly understood. The present study reports on structural and ultrastructural studies of the developing thyroid gland in embryos of the grass snake Natrix natrix L. At the time of oviposition, the thyroid primordium occupied its final position in the embryos. Throughout developmental stages I–IV, the undifferentiated thyroid primordium...
Reptilian myotomal myogenesis is poorly understood. This paper reports on structural, ultrastructural and immunocytochemical studies of muscle differentiation in sand lizard (Lacerta agilis) embryos. During somitogenesis, the somites are composed of epithelial vesicles with a centrally located somitocoel. At later developmental stages the ventral portion of the somite cortex disaggregates into the...
The origin of turtles has been a persistent unresolved problem involving unsettled questions in embryology, morphology, and paleontology. New fossil taxa from the early Late Triassic of China (Odontochelys) and the Late Middle Triassic of Germany (Pappochelys) now add to the understanding of (i) the evolutionary origin of the turtle shell, (ii) the ancestral structural pattern of the turtle skull,...
Wild snake diets are difficult to study using traditional methods, but stable isotopes offer several advantages, including integrating dietary information over time, providing data from individuals that have not fed recently, and avoiding bias towards slowly-digesting prey items. We used stable isotope signatures of carbon and nitrogen from scale tissue, red blood cells, and blood plasma to assess...
The different vascular distensibilities of systemic and pulmonary circuits were recently proposed as an important mechanism defining the direction of cardiac shunt and the distribution of cardiac output in vertebrates with undivided cardiac ventricles. In short, the more distensible pulmonary vascular bed was proposed to accommodate a larger portion of the blood ejected from the heart when cardiac...
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