The yolk sac roller coaster

Image of the mouse yolk sac, an extra-embryonic structure that is especially important for nutrient provision during the first half gestation, before formation of the functional placenta at embryonic day 9.5 of development. The visceral endoderm (green) attaches to the extraembryonic mesoderm (red) to generate yolk sac blood islands, the first site of hematopoiesis in mammalian embryos.


  1. Initiatives