The ectoderm is one of the three primary germ layers formed in early embryonic development. It is the outermost layer and is superficial to the mesoderm (the middle layer) and endoderm (the innermost layer). It emerges and originates from the outer layer of germ cells.
The blastoderm now consists of three layers an outer ectoderm a middle mesoderm and an inner endoderm ; each has distinctive characteristics and gives rise to certain tissues of the body. For many mammals it is sometime during formation of the germ layers that implantation of the embryo in the uterus of the mother occurs.
Endoderm – Wikipedia
Development of the human body – Wikipedia
An embryo is the early stage of development of a multicellular organism.In general in organisms that reproduce sexually embryonic development is the part of the life cycle that begins just after fertilization and continues through the formation of body structures such as tissues and organs. Each embryo starts development as a zygote a single cell resulting from the fusion of gametes (i.e …
In all bilaterian animals the mesoderm is one of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and endoderm ( inside layer) with the mesoderm as the middle layer between them. The mesoderm forms mesenchyme mesothelium non-epithelial blood cells and coelomocytes.
Endoderm is the innermost of the three primary germ layers in the very early embryo. The other two layers are the ectoderm and mesoderm with the endoderm being the innermost layer. Cells migrating inward along the archenteron form the inner layer of the gastrula which develops into the endoderm. The endoderm consist…