• M S Khaparde

      Articles written in Proceedings – Animal Sciences

    • Early development, implantation and amniogenesis in the Indian vampire bat,Megaderma lyra lyra (Geoffroy)

      A Gopalakrishna M S Khaparde

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      The embryo ofMegaderma lyra lyra enters the uterus as a morula. The blastocyst establishes contact with the uterine wall circumferentially at the level of implantation. The orientation of the embryonic mass at early stages is variable, but the flat embryonic disc at later stages is invariably mesometrially oriented. The preimplantation response of the uterus is markedly evident in the enormous expansion of the uterine glands and the hypertrophy of their cells. After the attachment of the blastocyst there is a rapid degeneration of the uterine glands and the cells of the endometrial stroma resulting in the formation of a thick zone of symplasma into which roots of the trophoblast enter. The maternal blood capillaries increase in number and their endothelial cells undergo hypertrophy. The amniotic cavity is formed by cavitation, but with the expansion of the embryonic disc the original roof of the amnion undergoes rupture and loss. The definitive amnion is formed by the development of folds from the margin of the embryonic disc.

    • Development of the foetal membranes and placentation in the Indian false vampire bat,Megaderma lyra lyra (Geoffroy)

      A Gopalakrishna M S Khaparde

      More Details Abstract Fulltext PDF

      The amnion expands to accommodate the growing foetus without undergoing any noticeable histological change. The yolk sac is large and forms an extensive chorio-vitelline placenta on the lateral sides of the uterus during early stages of gestation. However, due to the extension of the exocoelom and the expansion of the amniotic cavity the vascular splanchnopleure of the yolk sac is separated from the placenta and is invaginated towards the abembryonic trilaminar omphalopleure. The endodermal cells of the yolk sac hypertrophy as the yolk-sac wall gets vascularized, and the mesodermal cells enlarge only during the final stages of pregnancy. The allantoic vesicle, which is large during early stages of gestation, becomes progressively reduced and is finally lost during the final stages of pregnancy. The placenta, which is extensive during early stages, becomes restricted to a discoidal structure on the mesometrial side of the uterus. The definitive placenta is labyrinthine and vasomonochorial. Numerous free chorionic villi, which come into direct contact with the decidua at the margin of the placental disc, constitutes an accessory syndesmochorial placenta.

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