types of neuroglia in the central nervous system
Neuroglia Neuroglia also called glial cells, or simply glia (Greek γλία and γλοία "glue"; pronounced in English as either /ˈɡliːə/ or /ˈɡlaɪə/), are non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the central and peripheral nervous systems.[1] In the central nervous system, glial cells include oligodendrocytes, astrocytes, ependymal cells and microglia, and in the peripheral nervous system glial cells include Schwann cells and satellite cells.
Central canal Throughout the cervical and thoracic regions the central canal is situated in the anterior third of the spinal cord; in the lumbar enlargement it is near the middle, and in the conus medullaris it approaches the posterior surface. It is filled with cerebrospinal fluid, and lined by ciliated, columnar epithelium, outside of which is an encircling band of gelatinous substance, the substantia gelatinosa centralis (or central gelatinous substance of spinal cord). This gelatinous substance consists mainly of neuroglia, but contains a few nerve cells and fibers; it is traversed by processes from the deep ends of the columnar ciliated cells which line the central canal.