The NERVOUS SYSTEM lacks connective tissue and bone, however, the skull and vertebral canal act as an exoskeleton. The glial cellular organization of the nervous system comprises an internal skeleton. CNS astrocytes and oligodendroglia while PNS supporting cells function while the PNS composed of supporting cells (satellite cells) and Schwann cells.
Among fibrous astrocytes in white mater are Oligodendroglia. The oligo population represents a significant number of cells in the CNS. Oligos have multiple projections to pathway axons. Each oligo is the source of an internode of myelin. Each cell has multiple projections of plasma membranes that wrap a segment of a single axon while projections from other oligos contact different axonal sources. Wrapping of the oligo membrane produces tight layers of CNS myelin.
