Feb 28, 2009 Views: 2285
Important Cells of the Nervous System
Neurons are the backbone of the central nervous system (CNS), originate from neural stem cells (NSCs) and are electrically excitable cells which transmit information to the brain or different centers of the nervous system. Glial cells (or neuroglia) support neurons in the CNS. They don't carry nerve impulses but help modulating neurotransmission, as well as providing insulation, nutrition and support. Microglial cells, astrocytes and oligodendrocytes are the types of known glial cells. With the exception of microglia, the other two glial cells are of ectodermal origin in the developing embryo.
Astrocytes are involved in the physical structure of the brain and provide neurons with essential nutrients. They originate from NSCs that differentiate into glial-restricted precursors (GRPs). GRPs may then develop into astrocyte precursor cells (APCs) from which astrocytes derive. Oligodendrocytes, in the form of myelin sheaths, provide insulation for axons in the CNS and aid the conduction of electrical signals. Oligodendrocytes arise from oligodendrocyte precursor cells (OPCs). Microglial cells are the first and main form of immune defense in the CNS. They act during neuroinflammation by stimulating the release of proinflammatory cytokines and chemokines. Unlike all other glial cells, microglial cells originate from hemopoietic stem cells in the bone marrow and constantly migrate around the nervous system looking for neural damage and intruders.