Download Development of the central nervous system

Multimedial Unit of Dept.
Dept. of Anatomy JU
The nervous system develops from the neural plate,
a thickened, slipper-shaped area of embryonic ectoderm.
Notochord and paraaxial mesoderm induce the overlying
ectoderm to differentiate into the neural plate.
Signaling molecules appear to involve members of TGF-beta
family, which includes activin and FGFs.
The neural tube differentiates into the CNS,
consisting of the brain and spinal cord
The neural crest gives rise to cells that form most
of the PNS and ANS, consisting of cranial, spinal,
and autonomic ganglia
Neural tube and neural crest
Various stages of development of a neuroblast
neuroblast..
A neuron is a structural and functional unit consisting of the cell body and all its processes.
A. Motor axons growing out from neurons in the basal plate and centrally and peripherally growing
fibers of nerve cells in the dorsal root ganglion.
B. Nerve fibers of the ventral motor and dorsal sensory roots join to form the trunk of the spinal nerve.
Origin of the nerve cell and the various types of glial cells.
Neuroblasts,, fibrillar and protoplasmic astrocytes
Neuroblasts
astrocytes,, and ependymal cells originate from neuroepithelial
cells. Microglia develop from mesenchyme cells. The origin of the oligodendroglia is not clear.
A. Motor horn cell with naked rootlet.
B. B. In the spinal cordoligodendroglia cells surround the ventral rootlet; outside the spinal cord,
Schwann cells begin to surround the rootlet.
C. C. In the spinal cord the myelin sheath is formed by oligodendroglia cells; outside the spinal cord
the sheath is formed by Schwann cells.
Terminal end of the spinal cord in relation to that
of the vertebral column at various stages of development.
A. Approximately the third month
B. End of the fifth month
C. Newborn.
Differentiation of the neural tube
in the spinal cord during development
Development of the brain
Brain vesicles and their derivatives
Origins of Cranial Nerves and Their Composition
Contributions of Neural Crest Cells and Placodes to Ganglia of the Cranial Nerve