Ependymal Cells

Definition Of Ependymal Cells

Ependymal cells are a neuroglial cell type that lines the cavities of the ventricles within the brain and the central canal inside the spinal cord. The ciliated cells play an important role in generating, circulating, and regulating CSF, which, among other things, cushions the brain, removes metabolic wastes, and maintains a stable chemical environment. The ependymal cells provide a way for CSF to flow and thus protect the brain and spinal cord from hurt, providing smooth functioning of neural activity. They are, therefore, essential for the health and maintenance of the nervous system.

Structure Of Ependymal Cells

The structure of Ependymal cells is described below-

General Structure

Ependymal cells are the epithelium-like glial cells that line the ventricles of the brain and the central canal of the spinal cord. They are usually cuboidal or columnar, with cilia and microvilli on the apical surface. Their cilia circulate the CSF, and the microvilli participate in absorptive and secretory activities.

Types Of Ependymal Cells

Cuboidal or Columnar Ependymal Cells: These are the most common forms that line the ventricular system and the central canal. They form the majority of cells lining these structures and play an important role in CSF movement and homeostasis.

Specialised Ependymal Cells: They are tanycytes, localised to specific regions, for instance, within the third ventricle, that seem to have specific functions such as hormone transport and even participate in neuroendocrine signalling.

Function Of Ependymal Cells

The function of Ependymal cells are described below-

Role In The Central Nervous System

Ependymal cells play a crucial role in the formation and circulation of CSF, mechanically cushioning the brain and spinal cord, removing waste, and maintaining a very stable chemical environment. The ependymal cells are ciliated; their beats become coordinated to favour CSF flow within the ventricular system.

Barrier Function

Ependymal cells line the cavities of the central nervous system and form the blood-CSF barrier, which governs the blood-to-CSF exchange of substances. It protects the CNS from probably toxic compounds in the blood and gives a stable milieu to neural activity.

Support and Maintenance

They provide structural support to neural tissues and do associate intimately with other glial cell types to provide general maintenance and health of the nervous system. They play and could therefore have a role in the response to injury and disease through the control of neurogenesis and repair mechanisms.

Location Of Ependymal Cells

The location of Ependymal cells is described below-

Ventricular System

Ependymal cells form a continuous lining of the walls of the ventricles of the brain, where they contribute to the formation and circulation of CSF. Their position allows for the free flow and dissemination of CSF within the ventricular cavities of the brain.

Central Canal of the Spinal Cord

In the spinal cord, they line the central canal, providing a route for the circulation of CSF down the length of the spinal column. In other words, they become part of the mechanisms involved in maintaining the environment around the spinal cord—protective and nourishing.

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