Development
During the stage of neural plate formation the embryo consists of three cell layers: the ectoderm that eventually forms the skin and neural tissues, the mesoderm that forms muscle and bone, and the endoderm that will form the cells lining the digestive and respiratory tract. The progenitor cells that make up the precursors to neural tissues in the neural plate are called neuroepithelial cells. BMP-4 is a transforming growth factor that causes the cells of the ectoderm to differentiate into skin cells.
Without BMP-4 the ectoderm cells would automatically develop into neural cells. Axial mesoderm cells under the ectoderm secrete inhibitory signals called chordin, noggin and follistatin. These inhibitory signals inhibit BMP-4 and as a result cause the overlying cells of the ectoderm to develop into neural cells. The cells in the ectoderm that circumvent these neural cells do not receive the BMP-4 inhibitor signals and as a result BMP-4 induces these cells to develop into skin cells.
As the neural plate develops, it becomes surrounded by neural folds, which eventually create the cylindrical neural tube. This process is termed primary neurulation.
Read more about this topic: Neural Plate
Famous quotes containing the word development:
“The work of adult life is not easy. As in childhood, each step presents not only new tasks of development but requires a letting go of the techniques that worked before. With each passage some magic must be given up, some cherished illusion of safety and comfortably familiar sense of self must be cast off, to allow for the greater expansion of our distinctiveness.”
—Gail Sheehy (20th century)
“The Cairo conference ... is about a complicated web of education and employment, consumption and poverty, development and health care. It is also about whether governments will follow where women have so clearly led them, toward safe, simple and reliable choices in family planning. While Cairo crackles with conflict, in the homes of the world the orthodoxies have been duly heard, and roundly ignored.”
—Anna Quindlen (b. 1952)
“Ultimately, it is the receiving of the child and hearing what he or she has to say that develops the child’s mind and personhood.... Parents who enter into a dialogue with their children, who draw out and respect their opinions, are more likely to have children whose intellectual and ethical development proceeds rapidly and surely.”
—Mary Field Belenky (20th century)