Ventricular system
Ventricular system | |
---|---|
Interventricular foramina (Monro) Yellow - Third ventricle Red - Cerebral aqueduct (Sylvius) Purple - fourth ventricle Green - continuous with the central canal (Parts between median aperture and subarachnoid space are not shown) | |
Details | |
Identifiers | |
Latin | ventriculi cerebri |
MeSH | D002552 |
NeuroNames | 2497 |
FMA | 242787 |
Anatomical terms of neuroanatomy] |
In neuroanatomy, the ventricular system is a set of four interconnected cavities known as cerebral ventricles in the brain.[1][2] Within each ventricle is a region of choroid plexus which produces the circulating cerebrospinal fluid (CSF). The ventricular system is continuous with the central canal of the spinal cord from the fourth ventricle,[3] allowing for the flow of CSF to circulate.[3][4]
All of the ventricular system and the central canal of the spinal cord are lined with ependyma, a specialised form of epithelium connected by tight junctions that make up the blood–cerebrospinal fluid barrier.[2]
Structure
The system comprises four ventricles:[5]
- lateral ventricles right and left (one for each hemisphere)
- third ventricle
- fourth ventricle
There are several
Name | From | To |
interventricular foramina (Monro) |
lateral ventricles | third ventricle |
Cerebral aqueduct (Sylvius) | third ventricle | fourth ventricle |
Median aperture (Magendie) | fourth ventricle | subarachnoid space via the cisterna magna
|
Right and left lateral apertures (Luschka) | fourth ventricle | subarachnoid space via the cistern of great cerebral vein
|
Ventricles
The four cavities of the human brain are called ventricles.[6] The two largest are the lateral ventricles in the cerebrum, the third ventricle is in the diencephalon of the forebrain between the right and left thalamus, and the fourth ventricle is located at the back of the pons and upper half of the medulla oblongata of the hindbrain. The ventricles are concerned with the production and circulation of cerebrospinal fluid.[7]
Development
The structures of the ventricular system are
As the part of the primitive neural tube that will develop into the brainstem, the neural canal expands dorsally and laterally, creating the fourth ventricle, whereas the neural canal that does not expand and remains the same at the level of the midbrain superior to the fourth ventricle forms the cerebral aqueduct. The fourth ventricle narrows at the obex (in the caudal medulla), to become the central canal of the spinal cord.[citation needed]
In more detail, around the third week of development, the embryo is a three-layered disc. The embryo is covered on the dorsal surface by a layer of cells called ectoderm. In the middle of the dorsal surface of the embryo is a linear structure called the notochord. As the ectoderm proliferates, the notochord is dragged into the middle of the developing embryo.[8]
As the
- The telencephalon, which forms the cortex of the developed brain, and the diencephalon. The ventricles contained within the telencephalon become the lateral ventricles, and the ventricles within the diencephalon become the third ventricle.
- The rhombencephalon divides into a aqueduct of Sylvius.
Separating the anterior horns of the lateral ventricles is the
Function
Flow of cerebrospinal fluid
The ventricles are filled with
The fluid then flows around the
The cerebral aqueduct between the third and fourth ventricles is very small, as are the foramina, which means that they can be easily blocked.
Protection of the brain
The brain and spinal cord are covered by the
The CSF that is produced in the ventricular system is also necessary for chemical stability, and the provision of nutrients needed by the brain. The CSF helps to protect the brain from jolts and knocks to the head and also provides buoyancy and support to the brain against gravity. (Since the brain and CSF are similar in density, the brain floats in neutral buoyancy, suspended in the CSF.) This allows the brain to grow in size and weight without resting on the floor of the cranium, which would destroy nervous tissue.[11][12]
Clinical significance
The narrowness of the cerebral aqueduct and foramina means that they can become blocked, for example, by blood following a hemorrhagic stroke. As cerebrospinal fluid is continually produced by the choroid plexus within the ventricles, a blockage of outflow leads to increasingly high pressure in the
Other diseases of the ventricular system include inflammation of the membranes (
During
The
Whether the enlarged ventricles is a cause or a result of schizophrenia has not yet been established. Enlarged ventricles are also found in organic dementia and have been explained largely in terms of environmental factors.[13] They have also been found to be extremely diverse between individuals, such that the percentage difference in group averages in schizophrenia studies (+16%) has been described as "not a very profound difference in the context of normal variation" (ranging from 25% to 350% of the mean average).[14]
The
Additional media
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Transverse dissection showing the ventricles of the brain.
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3D Model of ventricular system
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Scheme showing relations of the ventricles to the surface of the brain.
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Drawing of a cast of the ventricular cavities, viewed from above.
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View of ventricles and choroid plexus
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Lateral ventricles along with subcortical structures, in glass brain
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Brain Ventricles Anatomy
See also
References
- ISBN 978-0-323-39632-5.
The ventricular system is an elaboration of the lumen of cephalic portions of the neural tube, and its development parallels that of the brain.
- ^ ISBN 978-0-323-07307-3.
The ventricles contain the choroid plexus, which produces CSF, and serve as conduits for CSF flow in the CNS. Ventricular walls are lined with ependymal cells, which are connected by tight junctions and constitute a CSF-brain barrier.
- ^ ISBN 978-0-323-07307-3.
The ventricular system arises from the hollow space within the developing neural tube and gives rise to cisterns within the CNS, from the brain to the spinal cord.
- S2CID 71013935.
Cerebrospinal fluid flows in bulk from sites of production to sites of absorption. Fluid formed in the lateral ventricles flows through the paired interventricular foramina (foramen of Monro) into the third ventricle, then through the mesencephalic aqueduct (aqueduct of Sylvius) into the fourth ventricle. The majority of CSF exits from the fourth ventricle into the subarachnoid space; a small amount may enter the central canal of the spinal cord.
- ISBN 978-1-947172-04-3.
- ^ National Institutes of Health (December 13, 2011). "Ventricles of the brain". nih.gov.
- ^ International school of medicine and applied sciences kisumu library
- ^ ISBN 9780443068119.
- PMID 19763105.
- ^ PMID 20807962.
- ^ Klein, S.B., & Thorne, B.M. Biological Psychology. Worth Publishers: New York. 2007.
- ^ Saladin, Kenneth S. Anatomy & Physiology. The Unit of Form and Function. 5th Edition. McGraw-Hill: New York. 2007
- PMID 17415783.
- PMID 12124914.
- PMID 14990758.
- PMID 15013837.
- PMID 12533327.
- PMID 19535999.