Ontogeny of cardiovascular and respiratory physiology in lower vertebrates.

The ontogeny of cardiovascular and respiratory physiology in vertebrates has been, and continues to be, an area of intense study (45, 87, 124, 28, 105, see Annual Review of Physiology 1984. 46:617-703). While clinicial benefits accrue from a knowledge of the developmental physiology of fetal mammals, much of the motivation for general vertebrate research on this topic stems from a fascination with the inherent complexity of developmental transitions of these systems. Indeed, some of the most radical developmental transitions of any organ system occur in heart, vasculature, and gas exchange organs of animals as they make the transition from embryonic/larval/fetal life to that of free-living animals. This review examines the cardiovascular and respiratory transitions that accompany development in fishes, amphibians, and reptiles. In many cases these processes are very similar to those occurring in birds and mammals and reflect the strong commonalities of vertebrate development. There are also fascinating differences, however, that deserve emphasis. Unfortunately, all