Sam Schmidt Paralysis Foundation a cell body, which houses the nucleus. Axons and dendrites form extensions from the cell body. Glial cells are "nerve-helper" cells that provide structural support, nourishment and protection for neurons. Astrocytes, a kind of glial cell, are the primary support cells of the brain and spinal cord. They make and secrete proteins called neurotrophic factors, which assist in the maintenance of nerve cells in the central nervous system. They also break down and remove proteins or chemicals that might be harmful to neurons (for example, glutamate, a neurotransmitter that in excess causes cells to become overexcited and die by a
Radial glial cell to replace lost or damaged tissue in a process known as gliosis. Radial glial cells originate from the transformation of neuroepithelial cells that form the neural plate during the early phases of pre-natal neurogenesis. This process is mediated through the down-regulation of epithelium-related protein expression (such as tight junctions) and an up-regulation of glial-specific features such as glycogen granules, the astrocyte glutamate transporter (GLAST), the intermediate filament vimentin, and, in some instances, including humans, glial fibrillary acidic protein (GFAP). After this transition, radial glia retain many of the original characteristics of neuroepithelial cells including: their apical-basal polarity, their position along