Ventricular system 276465 221085566 2008-06-23T00:09:53Z 76.92.155.46 /* Flow of cerebrospinal fluid */ {{Infobox Brain| Name = Cerebral ventricles | Latin = | GraySubject = | GrayPage = | Image = Gray734.png | Caption = Scheme showing relations of the ventricles to the surface of the brain. | Image2 = Gray735.png | Caption2 = Drawing of a cast of the ventricular cavities, viewed from above. | IsPartOf = | Components = | Artery = | Vein = | BrainInfoType = ancil | BrainInfoNumber = 192 | MeshName = Cerebral+Ventricles | MeshNumber = A08.186.211.276 | }} The '''ventricular system''' is a set of structures in the [[brain]] continuous with the [[central canal]] of the [[spinal cord]]. ==Components== The system comprises four ventricles: * right and left [[lateral ventricles]] * [[third ventricle]] * [[fourth ventricle]] there are a few little holes in the brain leading from these ventricles, though only the first two of the list below are generally considered part of the ventricular system: {| class="wikitable" | '''Name''' || '''From''' || '''To''' |- | right and left [[interventricular foramina]] (Monro) || lateral ventricles || third ventricle |- | [[cerebral aqueduct]] (Sylvius) || third ventricle || fourth ventricle |- | [[Median aperture]] (Magendie) || fourth ventricle || [[subarachnoid space]]/[[cisterna magna]] |- | right and left [[Lateral aperture]] (Luschka) || fourth ventricle || subarachnoid space/[[cistern of great cerebral vein]] |} Each ventricle contains a [[choroid plexus]] that produces [[cerebrospinal fluid]] (CSF) used to bathe and cushion the brain and spinal cord within their bony confines. ==Ventricles== There are four cerebral ventricles: the paired lateral ventricles, and midline the third and fourth ventricles. The two lateral ventricles, located within the [[cerebrum]], are relatively large and C-shaped, roughly wrapping around the dorsal aspects of the [[basal ganglia]]. It is in the lateral ventricles of the embryo that the successive generation of [[neurons]] gives rise to the 6-layered structure of the [[neocortex]], constructed from the inside out during development. Each lateral ventricle extends into the [[frontal lobes|frontal]], [[temporal lobes|temporal]] and [[occipital|occipital lobes]] via the frontal (anterior), temporal (inferior), and occipital (posterior) horns, respectively. The lateral ventricles both communicate via the [[interventricular foramina]] with the third ventricle, found centrally within the [[diencephalon]]. The third ventricle communicates via the [[Mesencephalic duct|cerebral aqueduct]], located within the [[midbrain]], with the fourth ventricle, found within the [[hindbrain]]. The three foramina to the [[subarachnoid space]] are found here, permitting cerebrospinal fluid produced in the ventricles to surround the [[brainstem]], [[cerebellum]], and [[cerebral cortex]]. The fourth ventricle is also continuous with the central canal, allowing CSF to bathe the inside surface of the spinal cord as well. ==Flow of cerebrospinal fluid== Cerebrospinal fluid is produced by modified [[ependymal cell]]s of the [[choroid plexus]] found in all components of the ventricular system except for the [[cerebral aqueduct]] and the occipital and frontal horns of the lateral ventricles. CSF flows from the lateral ventricles via the foramina of Monro into the third ventricle, and then the fourth ventricle via the cerebral aqueduct in the [[brainstem]]. From there it can pass into the central canal of the spinal cord or into the cisterns of the subarachnoid space via three small foramina: the central [[foramen of Magendie]] and the two lateral [[foramina of Luschka]]. The fluid then flows around the superior sagittal sinus to be reabsorbed via the [[arachnoid villi]] into the venous system. CSF within the spinal cord can flow all the way down to the [[lumbar cistern]] at the end of the cord around the [[cauda equina]] where [[lumbar puncture]]s are performed. The aqueduct between the third and fourth ventricles is very small, as are the foramina, which means that they can be easily blocked, causing high pressure in the lateral ventricles. This is a common cause of [[hydrocephalus]]--otherwise known as ''water in the brain''--and is an extremely serious condition due to both the damage caused by the pressure as well as nature of whatever caused the block (possibly a [[tumour]] or [[inflammation|inflammatory]] swelling). ==Protection of the brain== The brain and spinal cord are covered by a series of tough membranes called [[meninges]], which protect these organs from rubbing against the bones of the [[skull]] and [[Vertebral column|spine]]. The cerebrospinal fluid within the skull and spine is found between the [[pia mater]] and the arachnoid meninges and provides further cushioning. ==Role in disease== Diseases of the ventricular system include abnormal enlargement (hydrocephalus) and inflammation of the CSF spaces ([[meningitis]], ventriculitis) caused by [[infection]] or introduction of [[blood]] following trauma or [[hemorrhage]]. {{main|meningitis|hydrocephalus|cerebral hemorrhage|subarachnoid hemorrhage}} Interestingly, [[scientific method|scientific]] study of [[Computed tomography|CAT scan]]s of the ventricles in the late 1970s revolutionized the study of [[mental illness]]. Researchers found that patients with [[schizophrenia]] had enlarged ventricles compared to healthy subjects. This became the first "evidence" that mental illness was [[Biology|biological]] in origin and led to a reinvigoration of the study of such conditions via modern scientific techniques. Whether the enlargement of the ventricles is a cause or a result of schizophrenia has not yet been ascertained, however. Nowadays, [[magnetic resonance imaging]] (MRI) has superseded the use of CAT in research into the role of ventricular abnormalities in psychiatric illness. ==Development== <!--Development of ventricular system redirects here--> The structures of the ventricular system are [[embryogenesis|embryologically]] derived from the centre of the [[neural tube]] (the neural canal). ===In brainstem=== elaini is a primitive neural tube that will become the [[brain stem]] develops, the neural canal expandsleft and right 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]]. Likewise, the neural canal in the [[spinal cord]] that does not change forms the [[central canal]]. ==Additional images== <gallery> Image:Gray716.png|Coronal dissection showing the ventricles of the brain. </gallery> ==External links== * {{BrainMaps|Lateral%20Ventricle}} * [http://www.cartage.org.lb/en/kids/science/Biology%20Cells/Nervous%20System/Explore%20the%20Nervous%20System/Brain%20Basics/Ventricles/vent.html ventricular system and CSF] (concise description, Uni Washington) * [http://www.answers.com/topic/cerebrospinal-fluid?cat=health CSF at answers.com] (brief description, excellent diagram of CSF flow) ==References== * Purves D, Augustine GJ, Fitzpatrick D, Hall WC, Lamantia AS, McNamara JO, Williams SM, ''Neuroscience'' (third edition). Sinauer Associates Inc, July 2004. ISBN 0-87893-725-0 * Edgley S et al, '''Neuroanatomy''' from the Department of Anatomy, University of Cambridge. {{Ventricular system}} [[Category:Neuroanatomy]] [[Category:Central nervous system]] [[Category:Cerebrum]] [[de:Ventrikelsystem]] [[he:חדרי המוח]] [[nl:Ventrikelstelsel]] [[ja:側脳室]] [[pl:Komory mózgu]] [[pt:Sistema ventricular]] [[ro:Ventriculii cerebrali]] [[sv:Ventrikelsystemet]]