Mesoderm is one of the three germ layers, groups of cells that interact early during the embryonic life of animals and from which organs and tissues form.
Early in the process of development, vertebrate embryos develop a fold on the neural plate where the neural and epidermal ectoderms meet,
Étienne Geoffroy Saint-Hilaire, commonly known as Geoffroy, studied animals, their anatomy and their embryos, and teratogens at the National Museum of Natural History in Paris, France in the eighteenth and nineteenth centuries.
A germ layer is a group of cells in an embryo that interact with each other as the embryo develops and contribute to the formation of all organs and tissues. All animals, except perhaps sponges, form two or three germ layers.
Ectoderm is one of three germ layers—groups of cells that coalesce early during the embryonic life of all animals except maybe sponges, and from which organs and tissues form. As an embryo develops, a single fertilized cell progresses through multiple rounds of cell division.
The hedgehog signaling pathway is a mechanism that regulates cell growth and differentiation during embryonic development, called embryogenesis, in animals. The hedgehog signaling pathway works both between cells and within individual cells. The hedgehog