Ependyma
Encyclopedia
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).
that line the CSF-filled ventricle
s in the brain and the central canal
of the spinal cord. The cells are ciliated simple cuboidal epithelium. 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.
believe that ependyma is the prime candidate for the location of neural stem cells. 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.
Epithelium
Epithelium is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. Epithelial tissues line the cavities and surfaces of structures throughout the body, and also form many glands. Functions of epithelial cells include secretion, selective...
lining the ventricular system
Ventricular system
The ventricular system is a set of structures containing cerebrospinal fluid in the brain. It is continuous with the central canal of the spinal cord.-Components:The system comprises four ventricles:* right and left lateral ventricles* third ventricle...
of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
and the spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
. Ependyma is one of the four types of neuroglia in the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
. It is involved in the production of cerebrospinal fluid
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
(CSF).
Ependymal Cells
The ependyma is made up of ependymal cells. These are the epithelial cellsCell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
that line the CSF-filled ventricle
Ventricular system
The ventricular system is a set of structures containing cerebrospinal fluid in the brain. It is continuous with the central canal of the spinal cord.-Components:The system comprises four ventricles:* right and left lateral ventricles* third ventricle...
s in the brain and the central canal
Central canal
For the engineering project, see Indiana Central Canal.The central canal is the cerebrospinal fluid-filled space that runs longitudinally through the length of the entire spinal cord. The central canal is contiguous with the ventricular system of the brain...
of the spinal cord. The cells are ciliated simple cuboidal epithelium. 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
Glial cell
Glial cells, sometimes called neuroglia or simply glia , are non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the brain, and for neurons in other parts of the nervous system such as in the autonomous nervous system...
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
Choroid plexus
The choroid plexus is a structure in the ventricles of the brain where cerebrospinal fluid is produced...
, 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.
Stem cells
Jonas Frisén and his colleagues at the Karolinska Institute in StockholmStockholm
Stockholm is the capital and the largest city of Sweden and constitutes the most populated urban area in Scandinavia. Stockholm is the most populous city in Sweden, with a population of 851,155 in the municipality , 1.37 million in the urban area , and around 2.1 million in the metropolitan area...
believe that ependyma is the prime candidate for the location of neural stem cells. 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
Cochlea
The cochlea is the auditory portion of the inner ear. It is a spiral-shaped cavity in the bony labyrinth, making 2.5 turns around its axis, the modiolus....
to reverse hearing loss.