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:
“... work is only part of a man’s life; play, family, church, individual and group contacts, educational opportunities, the intelligent exercise of citizenship, all play a part in a well-rounded life. Workers are men and women with potentialities for mental and spiritual development as well as for physical health. We are paying the price today of having too long sidestepped all that this means to the mental, moral, and spiritual health of our nation.”
—Mary Barnett Gilson (1877–?)
“If you complain of people being shot down in the streets, of the absence of communication or social responsibility, of the rise of everyday violence which people have become accustomed to, and the dehumanization of feelings, then the ultimate development on an organized social level is the concentration camp.... The concentration camp is the final expression of human separateness and its ultimate consequence. It is organized abandonment.”
—Arthur Miller (b. 1915)
“Theories of child development and guidelines for parents are not cast in stone. They are constantly changing and adapting to new information and new pressures. There is no “right” way, just as there are no magic incantations that will always painlessly resolve a child’s problems.”
—Lawrence Kutner (20th century)