Ependymal Cells
Ependymal cells are ciliated glial cells that line the ventricles of the brain and the central canal of the spinal cord. They aid in the production and circulation of cerebrospinal fluid (CSF) and contribute to the formation of the blood–CSF barrier. These cells play a vital role in maintaining central nervous system (CNS) protection and homeostasis, making them an important concept for NEET Biology preparation.
This Story also Contains
- Introduction to Ependymal Cells
- Structure of Ependymal Cells
- Functions of Ependymal Cells
- Location of Ependymal Cells
- Ependymal Cells NEET MCQs (With Answers & Explanations)
- Recommended video on "Ependymal Cells"
Introduction to Ependymal Cells
Ependymal cells are a neuroglial cell type that are cuboidal to columnar cells arranged in a single layer that possess microvilli and cilia. These cells line the ventricles of the brain and central canal of the spinal cord (spaces filled with cerebrospinal fluid). The ciliated cells play an important role in generating, circulating, and regulating cerebrospinal fluid (CSF). They also form the blood–cerebrospinal fluid barrier. The ependymal cells provide a way for CSF to flow and thus protect the brain and spinal cord from injury. 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.
Functions of Ependymal Cells
The function of ependymal cells are described below:
Role in 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 toxic compounds in the blood and gives a stable milieu to neural activity.
Support and Maintenance
They provide structural support to neural tissues and associate intimately with other glial cell types to provide maintenance and health of the nervous system. They 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.
Ependymal Cells NEET MCQs (With Answers & Explanations)
Important topic for NEET exam are:
Structure and Functions of Ependymal cells
Location of Ependymal cells
Practice Questions for NEET
Q1. The CSF is circulated, produced and absorbed by
Neurosecretory cells
Ependymal cells
Both a and b
None of these
Correct answer: 2) Ependymal cells
Explanation:
Abundant mineral crystals exist and form the minerals most commonly known to occur, especially in the form of calcium oxalate, calcium carbonate, and silica. Besides the role played by minerals: structural support as well as defense against herbivory.
Cystoliths
Cystoliths are special deposits of calcium carbonate and usually occur in some epidermal cells of some plants. They characteristically occur among the species Acanthaceae and Urticaceae, especially stinging nettles.
Formation: Cystoliths are crystalline structures inside the cells and contribute to the rigidity and strength of the plant tissue.
Function: The hardness and toxicity of these deposits might provide them with some function apart from structural support to deter herbivores.
Concerning the crystal formation of mineral cystoliths, in general, it favours and enables the strong and flexible characteristics of the plants in that setting.
Hence, the correct answer is Option 2) Ependymal cells.
Q2. Assertion (A): Ependymal cells possess numerous microvilli.
Reason (R): The presence of microvilli facilitates the absorption of cerebrospinal fluid.
Both A and R are true and R is the correct explanation of A.
Both A and R are true but R is not the correct explanation of A.
A is true but R is false.
A is false but R is true.
Correct answer: 1) Both A and R are true and R is the correct explanation of A.
Explanation:
The Assertion is accurate. The central canal of the spinal cord and the ventricles of the brain are lined with ependymal cells, a kind of glial cell. On their apical surface, they have a lot of microvilli, which expands the area that is available for secretion and absorption.
The reason is also true because of this. The ependymal cells' microvilli on the apical surface let the cells absorb cerebrospinal fluid (CSF) from the brain's ventricles. These microvilli form a brush-like structure that aids in moving the CSF along the ependymal cells' surface and into the nearby blood veins.
Hence, the correct answer is option 1) Both A and R are true and R is the correct explanation of A.
Q3. Ependymal cells
Line the ventricles of the brain
Line the spinal cord cavity
Both a and b
None of these
Correct answer: 3) Both a and b
Explanation:
Ependymal cells:
Ependymal cells are epithelium-like cells that like the epithelium layer line the ventricles and the central canal of the spinal cord.
The surfaces of these cells possess numerous microvilli which help in the absorption of cerebrospinal fluid.
Ependymal cells are epithelial-like cells which like the epithelium layer line the ventricles and the central canal of the spinal cord.
Hence, the correct answer is option 3) Both a and b.
Also Read:
Recommended video on "Ependymal Cells"
Frequently Asked Questions (FAQs)
Recent developments in the research of ependymal cell regeneration and their functions in neurodegenerative diseases have been reported, with emerging technologies for better understanding of these cells.
Ependymal cells are glial cells lining the ventricles of the brain and in the central canal of the spinal cord. The primary function of these cells is the production and circulation of CSF.
Ependymal cells form the blood cerebrospinal fluid barrier thus helping to maintain the environment of the central nervous system and hence control the movement of the substance between blood and CSF.
The most common diseases include Ependymoma, a type of brain tumour originating in the Ependymal cells. The malfunction of the Ependymal cells results in impaired CSF circulation.
The Ependymal cells line the ventricles in the brain and the central canal in the spinal cord.