Ultrastructural studies on the heart-kidney complex of three species of protobranch bivalve molluscs
Morse, M.P.; Meyhöfer, E. (1990). Ultrastructural studies on the heart-kidney complex of three species of protobranch bivalve molluscs, in: Morton, B. (Ed.) The Bivalvia: Proceedings of a Memorial Symposium in honour of Sir Charles Maurice Yonge (1899-1986) at the 9th International Malacological Congress, 1986, Edinburgh, Scotland, UK. pp. 223-235
In: Morton, B. (Ed.) (1990). The Bivalvia: Proceedings of a Memorial Symposium in honour of Sir Charles Maurice Yonge (1899-1986) at the 9th International Malacological Congress, 1986, Edinburgh, Scotland, UK. Hong Kong University Press: Hong Kong. ISBN 962-209-273-X. 355 pp., more
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| Abstract |
Morphological and ultrastructural studies of the heart-kidney complex of the bivalve molluscs, Acila castrensis, Yoldia thraciaeformis and Y. limatula are reported. The heart in these species is tubular with marked differences in coloration between genera. Pericardial glands, located on the surface of the auricle, are composed of podocytes that are epithelial cells characterized by basal interdigitations of cytoplasmic pedicels. The resulting layer, fanned by pedicels from adjacent podocytes, is characterized by minute openings between the pedicels that along with the underlying basal lamina, provide an ultrafiltration barrier between the blood spaces and the pericardial cavity. The kidneys are diffuse, globular and V-shaped; a single-layered epithelium forms simple folds and tubules. A kidney cell is characterized by numerous vacuoles with varying granular content, apical microvilli and basal infolded membrane. Evidence for secretion and absorption are discussed. The presence of the respiratory pigment, haemocyanin, in the haemolymph is correlated with an active lifestyle. The tubular heart with paired auricles and ventricles, the auricular pericardial glands, the diffuse relatively undifferentiated kidney and the presence of haemocyanin are considered primitive characteristics and further demonstrate the cohesive nature of the protobranch subclass. |
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