Results 131 to 140 of about 3,723 (184)

Extraembryonic membrane development in a reproductively bimodal lizard, Lacerta (Zootoca) vivipara

Zoology, 2004
Reproductive mode has been remarkably labile among squamate reptiles and the evolutionary transition from oviparity to viviparity commonly has been accompanied by a shift in the pattern of embryonic nutrition. Structural specializations for placental transfer of nutrients during intrauterine gestation are highly diverse and many features of the ...
Stewart, James R., Heulin, Benoit, Surget-Groba, Yann   +2 more
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Effects of extraembryonic membrane deficiency on differentiation of the embryonic avian brain and sense organs

Cells Tissues Organs, 1967
Valerie Y. Knowlton
openalex   +3 more sources

Morphogenesis of extraembryonic membranes and placentation in Mabuya mabouya (Squamata, Scincidae)

Journal of Morphology, 2003
AbstractTopological and histological analyses of Mabuya mabouya embryos at different developmental stages showed an extraembryonic membrane sequence as follows: a bilaminar omphalopleure and progressive mesodermal expansion around the whole yolk sac at gastrula stages; mesodermal split and formation of an exocoelom in the entire embryonic chamber at ...
Adriana, Jerez, Martha Patricia, Ramírez-Pinilla   +1 more
openaire   +2 more sources

Formation of the Placenta and Extraembryonic Membranes

Annals of the New York Academy of Sciences, 1998
ABSTRACT: In eutherian mammals, the first cell types that are specified during embryogenesis are committed to form extraembryonic (placenta and fetal membranes) rather than embryonic structures. The trophoblast cell lineage, for example, forms at the morula‐to‐blastocyst transition: cells at the periphery of the morula become trophoblast, whereas ...
openaire   +2 more sources

Establishment of a rat placental cell line expressing characteristics of extraembryonic membranes

Developmental Biology, 1987
A cell line was derived from midgestation chorioallantoic placental explants of the outbred Holtzman rat. The cell line was found to express characteristics of extraembryonic membranes and to grow when introduced into allogeneic hosts. Growth in allogeneic hosts was detected following intraperitoneal injection of the cells but not following ...
M J, Soares, K D, Schaberg, C S, Pinal, S K, De, P, Bhatia, G K, Andrews   +5 more
openaire   +2 more sources

Somatic polyploidy in extraembryonic membranes of the snake,Elaphe guttata

Protoplasma, 1993
Video-densitometric DNA measurements of Feulgenstained tissues of 42 day old eggs of the corn snake,Elaphe g. guttata (Columbridae, Serpentes), revealed a basic DNA content of 2C=2.17 pg, with somatic polyploidy in the allantois, the chorioallontois, the yolk sac, and other extraembryonic membranes.
R. Meyer, W. Nagl
openaire   +1 more source

Monotreme development with particular reference to the extraembryonic membranes

Journal of Experimental Zoology, 1993
AbstractThis paper considers many of the salient features of monotreme development, particularly morphogenesis of the extraembryonic membranes.The uterine endometrium of both monotremes and marsupials exhibits a progesterone driven luteal phase where accelerated utilization of endometrial nutrients is evidenced by a rapid post‐primitive streak ...
openaire   +3 more sources

Ontogeny of the extraembryonic membranes of the oviparous lizard,Eumeces fasciatus (Squamata: Scincidae)

Journal of Morphology, 2000
Oviposited eggs of Eumeces fasciatus contain embryos in the limb bud stage. Amniogenesis is complete and two yolk sac membranes, vascular trilaminar omphalopleure (choriovitelline membrane) and bilaminar omphalopleure, enclose the yolk vesicle. A small allantoic vesicle contacts the chorion.
Stewart, James R., Florian, James D.
openaire   +2 more sources

Embryology of the sheep. I. Extraembryonic membranes and the development of body form

Journal of Morphology, 1972
AbstractThe developmental anatomy of the sheep in the early prenatal period (14 to 34 days) was studied using embryos of known coital age, and embryos of known size with estimated coital age. Characteristics of the embryos were studied by gross observation under the dissecting microscope, and by means of serial sections.
M M, Bryden, H E, Evans, W, Binns
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Radioautographic studies of DNA synthesis in the developing extraembryonic membranes of the mouse

The Anatomical Record, 1967
AbstractTritiated thymidine was injected into pregnant BALB/c mice intravenously at 8, 10, 12, 14 and 16 days of pregnancy. Radioautographs were prepared in order to determine the extent of synthesis of DNA in the extraembryonic membranes at the above stages of gestation. The extent of synthesis of DNA was expressed as a radioactive index. The index is
Saccoman, F M, Morgan, C F, Wells, L J
openaire   +2 more sources