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Ependymal cell)
Ependyma is the thin epithelial membrane lining the ventricular system of the brain and the spinal cord. Ependyma is one of the four types of neuroglia in the central nervous system. It is involved in the production of cerebrospinal fluid (CSF).
[edit] Ependymal Cells
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 cuboidal/columnar. 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.
[edit] Pathology
Ependymoma is a tumor of the ependymal cells.
[edit] Stem cells
Jonas Frisén and his colleagues at the Karolinska Institute in Stockholm believe that ependyma is the prime candidate for the location of neural stem cells.[1] One study observed that ependymal cells from the lining of the lateral ventricle might be a source for cells which can be transplanted into the cochlea to reverse hearing loss.[2]
[edit] References
- ^ Johansson CB, Momma S, Clarke DL, Risling M, Lendahl U, Frisen J (1999). "Identification of a neural stem cell in the adult mammalian central nervous system". Cell 96 (1): 25–34. doi:10.1016/S0092-8674(00)80956-3. PMID 9989494.
- ^ "Brain cell hope for hearing loss". BBC News. 2008-12-09. http://news.bbc.co.uk/2/hi/health/7770665.stm. Retrieved 2008-12-09.
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