.png){kind=icon}
Ectoderm
The nervous system develops from the outer layer, called the ectoderm (from the Greek ektos, "out," and derma, "skin"). As the cell layers thicken, they grow into a flat oval plate.
Hindbrain
At the anterior part of the neural tube, three subdivisions become apparent. One of these subdivisions corresponds to the future hindbrain (cerebellum, pons, and medulla).
Telencephalon
At the anterior part of the neural tube, three subdivisions become apparent. One of these subdivisions corresponds to the future forebrain, consisting of the telencephalon and the diencephalon.
Central canal
The interior of the neural tube becomes the cerebral ventricles of the brain, the central canal of the spinal cord, and the passages that connect them.
Diencephalon
At the anterior part of the neural tube, three subdivisions become apparent. One of these subdivisions corresponds to the future forebrain, consisting of the telencephalon and the diencephalon.
Endoderm
At 18 days the embryo has begun to implant in the uterine wall and consists of three layers of cells: endoderm, mesoderm, and ectoderm. The endoderm is the innermost of the three layers; it gives rise to the gut, liver, and lungs.
Neural crest
The neural crest is a collection of cells that form along the dorsal pole of the neural tube. The neural crest gives rise to neurons and glia of the peripheral nervous system.
Neural groove
About 20 days following fertilization, uneven rates of cell division in the ectoderm cause a groove to form along the midline of the embryonic ectoderm.
Mesoderm
At 18 days the embryo has begun to implant in the uterine wall and consists of three layers of cells: endoderm, mesoderm, and ectoderm. The mesoderm is the middle layer; it gives rise to connective tissue, muscle, and blood vessels.
Midbrain
At the anterior part of the neural tube, three subdivisions become apparent. One of these subdivisions corresponds to the future midbrain.
Neural plate
The nervous system develops from the outer layer of the embryo. As the cell layers thicken, they grow into a flat oval plate called the neural plate.
Neural tube
Between 20 and 22 days, the lateral edges of the neural plate come together, fold inward, and become a tube. This structure, called the neural tube, gives rise to the brain and spinal cord.
Neural plate
The nervous system develops from the outer layer of the embryo. As the cell layers thicken, they grow into a flat oval plate called the neural plate.
Spinal cord
The neural tube gives rise to the spinal cord.