Definition for Ependymal cell
From Biology Forums Dictionary
The ependyma is made up of ependymal cells. These are the epithelial cells that line the CSF-filled ventricles in the brain and the central canal of the spinal cord. The cells are ciliated simple cuboidal epithelium. Their apical surfaces are covered in a layer of cilia, which circulate CSF around the central nervous system. Their apical surfaces are also covered with microvilli, which absorb CSF. Ependymal cells are a type of Glial cell and are also CSF producing cells. Within the brain's ventricles, a population of modified ependymal cells and capillaries together form a system called the choroid plexus, which produces the CSF.
Tight junctions, zonae occludentes, between ependymal cells control fluid release across the epithelium. This release allows free exchange between CSF and nervous tissue of brain and spinal cord. This is why sampling of CSF (e.g. through a "spinal tap") gives one window to CNS.