We have the green cells that make up the endoderm. We have these red cells that make up the mesoderm and we have these blue cells that make up our actoderm. Now, the endoderm is the germ layer that eventually forms the epithelial layer of our digestive tract as well as the lungs, our liver and our pancreas and other structures such as the thyroid and parathyroid glands and the thymus. The mesoderm forms the muscular and the skeletal system as well as the cardiovascular system, the excretory system and the reproductive system while the ectoderm is what forms the skin as well as the nervous system. Now, before these blue cells can actually organize themselves and arrange themselves and differentiate into the cells that ultimately make up the central and the peripheral nervous system of our body, what must happen is a structure known as the noticort must actually form. And the noticort is formed from the cells found in the Masodum germ layer.