ISSN:
1432-136X
Keywords:
Calcium exchange
;
Gradients
;
Barriers
;
Clam
;
Anodonta cygnea
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract Electrical potential differences between the haemolymph and the extrapallial fluid, and between the haemolymph and the mantle cavity fluid, and ionic concentrations of calcium in the haemolymph and in extrapallial fluid were measured in vivo in Anodonta cygnea. The electrochemical potential of ionic calcium in the haemolymph is clearly above the electrochemical potential of ionic calcium in the environment and is very nearly in equilibrium with that of the extrapallial fluid. Simultaneous measurements of carbon dioxide partial pressure and pH in the extrapallial fluid showed that in this compartment ionic calcium is clearly above saturation. It is proposed that calcium deposition is regulated through the secretion of the organic matrix and by controlling the pH and the carbon dioxide partial pressure of the extrapallial fluid. An estimation of the minimum positive balance of calcium required to sustain shell growth together with the electrophysiological characterization of the mantle cavity epithelium showed that this tissue is not the route of entry of calcium into the animal.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00261665
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