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Advantages of heart reversal in pelagic tunicates

Published online by Cambridge University Press:  11 May 2009

A. C. Heron
A. C. Heron
Affiliation:
Division of Fisheries and Oceanography, CSIRO, Cronulla, N.S.W. 2230, Australia
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Extract

Most work in tunicate heart physiology has been directed towards finding the actual physiological cause of heart reversal rather than the adaptive advantage of it to the animal (see reviews by Krijgsman, 1956; Kriebel, 1968; Goodbody, 1974). Krijgsman (1956) concludes: ‘We do not know whether there is any functional significance in the periodic reversal of beat. One can see no reason why a permanent one-way circulation should not be efficient. Presumably the cause of reversal is the periodic exhaustion of the pacemakers, which has no physiological significance.’ Because of the abundance of pacemaker systems in nature in which periodic exhaustion does not take place, this conclusion should be re-examined.

Type
Research Article
Information
Journal of the Marine Biological Association of the United Kingdom , Volume 55 , Issue 4 , November 1975 , pp. 959 - 963
Copyright
Copyright © Marine Biological Association of the United Kingdom 1975

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References

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