Ependyma

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ependyma

[e′pen·də·mə]
(histology)
The layer of epithelial cells lining the cavities of the brain and spinal cord. Also known as ependymal layer.

Ependyma

 

cells in the brain of animals and man that perform demarcating, supportive, and secretory functions in the central nervous system; a form of neuroglia.

The ependyma separates from cells of the neural tube in early embryogenesis. Ependymal cells (ependymocytes) line the walls of the spinal canal and ventricles of the brain. They have elongated bodies with cilia at the free end. The cilia, which are lost in many parts of the brain after the individual is born, help the cerebrospinal fluid to circulate by their beating movements. A long, branched process extends from the opposite end of the ependymocyte into the brain. The ependyma of the walls of the third ventricle may promote the exchange of biologically active substances between neurons of the adjacent regions of the brain, cerebrospinal fluid, and blood vessels of the hypophyseoportal system.

References in periodicals archive ?
Kuo decided to study these cells because the lateral ventricles in the brain, where adult neural stem cells reside, are also the last area of a developing brain that grows ependymal cells.
Currently, when neural stem cells are harvested for growth in culture, however, the ependymal cells are not removed along with them.
astrocytes, oligodandrocytes and ependymal cells were in abundance in the treated groups as compared to the control group (Figs.
Later it was found that not only embryonic CNS but also adult CNS possess the ability to generate neurospheres forming cells in vitro, including neural epithelial progenitor (NEP) cells, radial glial cells, SVZ cells, and ependymal cells, that clonigenically generate neurons, astrocytes and oligodendrocytes in vivo (16).
In situ hybridization studies needed to determine whether expression includes neuronal and ependymal cells were not reported.
In this case, the ependyma is reconstituted by the transformation of the ependymal cells into nonepithelial mesenchymal cells, which proliferate from both edges of the lesion to bridge the gap, then transform back into epithelial cells, while axons regenerate to make functional synapses.
Mild lymphocytic perivascular cuffing and loss of Purkinje cells were observed in the cerebrum and cerebellum, and virus antigen was detected in ependymal cells and epithelium of the choroid plexus and in cerebellar Purkinje cells.
These tumors arise from the ependymal cells of the central canal; hence, they are located centrally, as opposed to the eccentric location of astrocytomas (Table 2).
Immunohistologic analysis confirmed systemic infection and revealed influenza virus nucleocapsid protein in 1) ganglions of the adrenal medulla, 2) ependymal cells of the central nervous system (associated with marked lymphocytic meningitis and perivascular cuffing), 3) thymus epithelia, and 4) epithelia of the exocrine pancreas (Figure 1).