By Levi Clancy for Student Reader on
All but one type of neuroglia (glial cells) are derived from same ectoderm that produces neurons. Most organs are from the mesoderm. There are six categories of neuroglia:
Neurolemmocytes (Schwann cells) form myelin layers around axons in the PNS.
Oligodendrocytes form myelin layers around axons in the CNS.
Microglia are derived from mesoderm and remove foreign and degenerated material in the CNS.
Astrocytes help regulate passage of molecules from blood to brain.
Ependymal cells line brain ventricles and central canal of spinal cord
Ganglionic gliocytes support neuron cell bodies within ganglia off the PNS.