Affiliation:
1. Zoophysiology, Department of Bioscience, Aarhus University, Aarhus, Denmark
2. Department of Ecology and Evolutionary Biology, University of California, Irvine, California, USA
Abstract
By virtue of their cardiovascular anatomy, reptiles and amphibians can shunt blood away from the pulmonary or systemic circuits, but the functional role of this characteristic trait remains unclear. It has been suggested that right-to-left (R-L) shunt (recirculation of systemic blood within the body) fuels the gastric mucosa with acidified and CO2-rich blood to facilitate gastric acid secretion during digestion. However, in addition to elevating PCO2, R-L shunt also reduces arterial O2 levels and would compromise O2 delivery during the increased metabolic state of digestion. Conversely, arterial PCO2 can also be elevated by lowering ventilation relative to metabolism (i.e. reducing the air-convection requirement, ACR). Based on a mathematical analysis of the relative roles of ACR and R-L shunt on O2 and CO2 levels, we predict that ventilatory modifications are much more effective for gastric CO2 supply with only modest effects on oxygen delivery. Conversely, elevating CO2 levels by means of R-L shunt would come at a cost of significant reductions in O2 levels. The different effects of altering ACR and R-L shunt on O2 and CO2 levels, is explained by the differences in the effective blood capacitance coefficients.
Funder
Natur og Univers, Det Frie Forskningsråd
Publisher
The Company of Biologists
Subject
Insect Science,Molecular Biology,Animal Science and Zoology,Aquatic Science,Physiology,Ecology, Evolution, Behavior and Systematics
Cited by
8 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献