Anatomy of the ovaries of the starfish Asterias rubens (Echinodermata) |
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Authors: | Schoenmakers H J N Colenbrander P H J M Peute J van Oordt P G W J |
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Institution: | (1) Laboratory of Chemical Animal Physiology and Section Comparative Endocrinology of the Zoological Laboratory, State University of Utrecht, Utrecht, The Netherlands;(2) Laboratory of Chemical Animal Physiology, State University of Utrecht, 8 Padualaan, 3508 TB Utrecht, The Netherlands |
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Abstract: | Summary The ovaries of the starfish Asterias rubens were studied histologically and ultrastructurally. The reproductive system in female specimens consists of ten separate ovaries, two in each ray. Each ovary is made up of a rachis with lateral primary and secondary folds: the acini maiores and acini minores. The ovarian wall is composed of an outer and an inner part, separated by the genital coelomic sinus. The ovarian lumen contains oocytes in various phases of oogenesis, follicle cells, nurse cells, phagocytosing cells and steroid-synthesizing cells.Oogenesis is divided into four phases: (i) multiplication phase of oogonia, (ii) initial growth phase of oocytes I, (iii) growth phase proper of oocytes I, and (iv) post-growth phase of oocytes I. The granular endoplasmic reticulum and the Golgi complex of the oocytes appear to be involved in yolk formation, while the haemal system, haemal fluid and nurse cells may also be important for vitellogenesis. The haemal system is discussed as most likely being involved in synchronizing the development of the ovaries during the annual reproductive cycle and in inducing, stimulating and regulating the function of the ovaries.Steroid-synthesizing cells are present during vitellogenesis; a correlation between the presence of these cells and vitellogenesis is discussed. |
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Keywords: | Ovaries Ovarian wall Oogenesis Steroid-synthesizing cells Asterias rubens |
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