Human embryogenesis is hallmarked by two phases of yolk sac development. The primate
hypoblast gives rise to a transient primary yolk sac, which is rapidly superseded by a …

Implantation of the human embryo begins a critical developmental stage that comprises
profound events including axis formation, gastrulation and the emergence of haematopoietic …

There are three fetal membranes in mammals, namely the yolk sac, allantois and amnion,
but only the first two form a placenta. In Monotremata (monotremes), Marsupialia …

The extraembryonic yolk sac (YS) ensures delivery of nutritional support and oxygen to the
developing embryo but remains ill-defined in humans. We therefore assembled a …

The yolk sac is the first observed site of hematopoiesis during mouse ontogeny. Primitive
erythroid cells are the most well-recognized cell lineages produced from this tissue. In …

Human embryogenesis entails complex signalling interactions between embryonic and
extra-embryonic cells. However, how extra-embryonic cells direct morphogenesis within the …

OBJECTIVE: To review the process of blood-cell formation in the murine and human yolk
sac. DATA SOURCES: Most articles were selected from the PubMed database. DATA …

The first blood cells observed in the embryo are large nucleated erythroblasts generated in
blood islands of the extraembryonic yolk sac. These unique red cells have been termed …

The mammalian blastocyst consists of three distinct cell types: epiblast, trophoblast (TB), and
primitive endoderm (PrE). Although embryonic stem cells (ESCs) and trophoblast stem cells …

In the embryo, the first hematopoietic cells derive from the yolk sac and are thought to be
rapidly replaced by the progeny of hematopoietic stem cells. We used three lineage-tracing …