Introduction to Ependymal Cell
The ependymal epithelium is best known for lining the ventricles of the brain. Ependymal cells are clearly defined as a subtype of glial cells because they are nonneuronal cells in the brain that are derived from neuroectoderm. They are made up of ependymocytes, choroid plexus epithelial cells, tanycytes, and Müller cells and retinal pigment epithelial cells.
Ependymal Cells Definition
Ependymal cells form an epithelial layer that lines the brain's ventricles and spinal cord's central canal, respectively. During active brain development, the mammalian ependyma is derived from the ventricular zone, which produces ependymal cells, neuroblasts, and glial cells.
Ependyma
The ependyma is the thin neuroepithelial (simple columnar ciliated epithelium) lining of the brain's ventricular system and the spinal cord's central canal. One of the four types of neuroglia in the central nervous system is the ependyma (CNS). It plays a role in the production of cerebrospinal fluid (CSF) and has been shown to act as a reservoir for neuroregeneration.
Structure
The ependyma is made up of glial cells called ependymocytes, which are ependymal cells. These cells line the ventricles of the brain and the spinal cord's central canal, which fill with cerebrospinal fluid. These are nerve tissue cells with a simple columnar shape, similar to mucosal epithelial cells. For their function in circulating cerebrospinal fluid, early monociliated ependymal cells differentiate into multiciliated ependymal cells.
These cells' basal membranes are distinguished by tentacle-like extensions that attach to astrocytes. Cilia and microvilli cover the apical side.
Function
Cerebrospinal Fluid- Ependymal cells, which line the CSF-filled ventricles and spinal canal, play an important role in CSF production and regulation. Their apical surfaces are covered in cilia, which help to circulate CSF around the CNS. Microvilli, which absorb CSF, cover their apical surfaces as well. A population of modified ependymal cells and capillaries known as the tela choroidea form the choroid plexus, which produces CSF, within the ventricles of the brain.
Neuroregeneration- Jonas Frisén and colleagues from the Karolinska Institute in Stockholm demonstrated that ependymal cells act as reservoir cells in the forebrain that can be activated after a stroke, as well as in vivo and in vitro stem cells in the spinal cord. These cells, however, did not self-renew and were depleted as they generated new neurons, failing to meet the requirement for stem cells. According to one study, ependymal cells from the lateral ventricle's lining may be a source of cells that can be transplanted into the cochlea to reverse hearing loss.
Ependymal Epithelium
The epithelial layer that surrounds the choroid plexus, a network of blood vessels located in the walls of the lateral ventricles, is also formed by ependymal cells (the two largest ventricles, which occur as a pair in the cerebral hemispheres).
Ependymal Cells Function
What are the ependymal cells functions? They are branched glial cells that nourish neurons while also acting as a barrier between nervous tissue and blood. Ependymal cells blood brain barrier protects against blood-borne infections.
FAQs on Ependymal Cell
1. What exactly are ependymal cells and where are they located in the body?
Ependymal cells are a type of glial cell, which means they are support cells in the nervous system. You can find them forming a special lining for the fluid-filled cavities in the brain, known as ventricles, and the central canal of the spinal cord.
2. What is the main job of ependymal cells?
The primary function of ependymal cells is to produce and help circulate cerebrospinal fluid (CSF). This fluid acts as a cushion for the brain and spinal cord, transports nutrients, and removes waste products. Many ependymal cells have tiny hair-like structures called cilia that beat to keep the CSF moving.
3. Are ependymal cells found in the Central Nervous System (CNS) or the Peripheral Nervous System (PNS)?
Ependymal cells are exclusively found in the Central Nervous System (CNS). This is because their job is directly related to the brain's ventricles and the spinal cord's central canal, which are the core components of the CNS.
4. How does the structure of an ependymal cell help it perform its function?
The structure of an ependymal cell is perfectly suited for its job. They are typically cuboidal or columnar in shape, allowing them to fit tightly together to form a barrier-like lining. Their surface often features:
- Cilia: These tiny, hair-like projections help to move and circulate the cerebrospinal fluid.
- Microvilli: These small, finger-like projections increase the surface area for absorbing substances from the CSF.
5. What might happen if a person's ependymal cells get damaged?
If ependymal cells are damaged, the flow and regulation of cerebrospinal fluid can be disrupted. This can lead to a serious condition called hydrocephalus, where CSF builds up inside the brain, increasing pressure. Damage can also impair the transport of vital molecules between the brain tissue and the CSF.
6. How are ependymal cells different from other glial cells like astrocytes?
While both are glial cells in the CNS, they have very different roles. Ependymal cells are mainly involved in producing and circulating CSF. In contrast, astrocytes provide structural and metabolic support to neurons, help form the blood-brain barrier, and regulate the chemical environment of the brain.
7. What is the relationship between ependymal cells and the choroid plexus?
The choroid plexus is the specific structure within the brain's ventricles responsible for producing the majority of CSF. This structure is essentially a network of capillaries covered by a specialised layer of ependymal cells. Therefore, ependymal cells are the key functional component of the choroid plexus that actively secretes CSF.
8. Besides managing CSF, do ependymal cells have any other roles?
Yes, while their main job is related to CSF, they have other important functions. They form the blood-CSF barrier, which carefully controls what substances can pass from the blood into the cerebrospinal fluid. Furthermore, some studies suggest that certain ependymal cells can act as neural stem cells, potentially playing a role in brain repair after injury.
