Cardiovascular Circuits and Digestive Function of Intermittent-Feeding Sauropsids

  • Rike Campen
  • Matthias Starck


Turtles, squamates, and crocodiles show remarkable morphological and physiological plasticity of their gastrointestinal tract in response to feeding. They also show a remarkably complicated and diverse morphology of their cardiovascular circuitry and cardiovascular functioning. In particular, many species have the option to bypass the pulmonary (or the systemic) circulation by redirecting blood into the systemic (or pulmonary) circulation, respectively. In this chapter we review the evidence that supports a functional integration of the gastrointestinal system with the cardiovascular system. In particular the morphology of the cardiovascular circuits suggests that both systems are tightly integrated. The main hypotheses about a functional integration are: (1) increased blood flow to the gastrointestinal system may provision more blood for transport, and also possibly drives inflation of the gastrointestinal tract after feeding. (2) Central redirection of blood may play a role for digestion by balancing the blood pH during the alkaline tide. (3) The anatomy of the vascular circuits suggests that CO2-rich blood is directed to the gastrointestinal tract to facilitate gastric acid production. We critically review the evidence and support for each of these ideas and outline avenues for future research that may ultimately help to clarify many of the contrasting ideas discussed in the literature. We conclude that the timing of shunting during digestion has not been fully explored; many important quantitative data (e.g., ventricle and blood volume, shunting volume) are completely missing; experimental studies are dominated by highly invasive studies with unclear effects on normal physiology; capillary filtration rate and the role of the lymphatic system have been neglected; and finally, volume compensation and compensatory shunts have largely been neglected.


Pulmonary Circulation Increase Blood Flow Dorsal Aorta Digestive Function Blood Flow Volume 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



We would like to thank the editor of this volume for his invitation to contribute a chapter. We would also like to express our grateful thanks to Colleen Farmer, Jeanette Wyneken and Kenneth Kardong, Tobias Wang, and Jim Hicks for stimulating discussions during the past years. Many of their thoughts have contributed directly or indirectly to the ideas outlined in this chapter. RC is supported by a fellowship from Elitenetzwerk Bayern.


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© Springer-Verlag Berlin Heidelberg 2012

Authors and Affiliations

  1. 1.Department of Biology IILudwig-Maximilians-University MunichMunichGermany

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