pouch formation, notochord, archenteron stage. the process of nerulation. human embryonic development.

archenteron baby ball biology blastocyst blastopore blastula cell cells development diagram division early ectoderm egg embryo embryology embryonic endoderm female fertility fertilization fertilized formation genetic growth health healthy human illustration implantation medical medicine microscopic morula notochord nucleus oocyte ovulation ovum pouch pregnancy reproduction reproductive science segmentation stage stages stem vector zygote