At the end of week 2 of development (day 14), what is the composition of the embryonic disk?
Epiblast only
Epiblast and hypoblast
Ectoderm and endoderm
Ectoderm, mesoderm, and endoderm
The embryoblast consists of the two distinct cell layers (epiblast and hypoblast) at the end of development week 2 (day 14) and forms the bilaminar embryonic disk. Second week is called week of 2 - 2 cavities- amniotic cavity and yolk sac cavity 2 type of embryoblast - Epiblast and hypoblast 2 type of trophoblast - Cytotrophoblast and Syncytial trophoblast Gastrulation - formation of 3 germ layers in week 3
Development period- week 1,2,3,4