Neural plate
Encyclopedia
In human embryology
, formation of neural plate is the first step of neurulation
. It is created by a flat thickening opposite to the primitive streak
of the ectoderm
.
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
.
Embryology
Embryology is a science which is about the development of an embryo from the fertilization of the ovum to the fetus stage...
, formation of neural plate is the first step of neurulation
Neurulation
Neurulation is the stage of organogenesis in vertebrate embryos, during which the neural tube is transformed into the primitive structures that will later develop into the central nervous system....
. It is created by a flat thickening opposite to the primitive streak
Primitive streak
The primitive streak is a structure that forms during the early stages of avian, reptilian and mammalian embryonic development.-Introduction:...
of the ectoderm
Ectoderm
The "ectoderm" is one of the three primary germ cell layers in the very early embryo. The other two layers are the mesoderm and endoderm , with the ectoderm as the most exterior layer...
.
Development
During the stage of neural plate formation the embryo consists of three cell layers: the previously mentioned 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-4Bone morphogenetic protein
Bone morphogenetic proteins are a group of growth factors also known as cytokines and as metabologens . Originally discovered by their ability to induce the formation of bone and cartilage, BMPs are now considered to constitute a group of pivotal morphogenetic signals, orchestrating tissue...
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
Reflection symmetry
Reflection symmetry, reflectional symmetry, line symmetry, mirror symmetry, mirror-image symmetry, or bilateral symmetry is symmetry with respect to reflection. That is, a figure which does not change upon undergoing a reflection has reflectional symmetry.In 2D there is a line of symmetry, in 3D a...
mesoderm cells under the ectoderm secrete inhibitory signals called chordin
Chordin
Chordin is a polypeptide that dorsalizes the developing embryo by binding ventralizing TGFβ proteins such as bone morphogenetic proteins. It may also play a role in organogenesis. There are five named isoforms of this protein that are produced by alternative splicing.In humans, the chordin peptide...
, noggin
Noggin (protein)
Noggin, also known as NOG, is a protein which in humans is encoded by the NOG gene.Noggin inhibits TGF-β signal transduction by binding to TGF-β family ligands and preventing them from binding to their corresponding receptors. Noggin plays a key role in neural induction by inhibiting BMP4, along...
and follistatin
Follistatin
Follistatin also known as activin-binding protein is a protein that in humans is encoded by the FST gene. Follistatin is an autocrine glycoprotein that is expressed in nearly all tissues of higher animals....
. 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
Neural folds
In front of the primitive streak two longitudinal ridges, caused by a folding up of the ectoderm, make their appearance, one on either side of the middle line...
, which eventually create the cylindrical neural tube
Neural tube
In the developing vertebrate, the neural tube is the embryo's precursor to the central nervous system, which comprises the brain and spinal cord...
. This process is termed primary neurulation
Neurulation
Neurulation is the stage of organogenesis in vertebrate embryos, during which the neural tube is transformed into the primitive structures that will later develop into the central nervous system....
.