Fisiologia

The Journal of Experimental Biology 204, 923–932 (2001) Printed in Great Britain © The Company of Biologists Limited 2001 JEB3097

923

CONTROL OF CARDIOVASCULAR FUNCTION AND ITS EVOLUTION IN CRUSTACEA
BRIAN R. MCMAHON Biological Sciences, The University of Calgary, Calgary, Alberta, Canada T2N 1N4 e-mail: [e-mail]

Accepted 1 December 2000; published on WWW 12 February 2001 Summary Work in the last decade has shown that crustacean open cardioarterial valves at the base of each artery. These circulatory systems are highly efficient and controlled in valves contain innervated muscle, and differential a complex manner. Control occurs at several levels. contraction serves to regulate the efflux of oxygenated Myocardial contraction is initiated in the cardiac ganglion haemolymph into a particular system. The major influence but constantly modulated by the central nervous system, on both the evolution and control of arthropod open blood both directly via the cardioregulatory nerves and indirectly vascular systems is efficiency of oxygen uptake and via the neurohormonal system. Heart rate and stroke delivery. This influence is illustrated by reference to a volume can be controlled independently and measurements variety of crustacean and other arthropod types. of both are needed to assess cardiac output accurately. Haemolymph outflow from many arthropod hearts is via a Key words: physiology, cardiovascular systems, Crustacea, complex multiarterial distribution system, and the regional Arthropoda, evolution, oxygen. distribution of cardiac output is tightly controlled via

Introduction Crustaceans, indeed arthropods generally, have an open circulatory system that can be loosely defined as a blood vascular system in which the circulating fluid (hæmolymph) passes, at some point, through tissues directly, i.e. in passages unbounded by endothelial walls. Within this definition, however, we find a very wide range of circulatory patterns ranging from