Ventricular system

From Freepedia

The ventricular system is a fluid conducting system within the brain. It is filled with cerebrospinal fluid (CSF) that is largely composed of water. The ventricular system serves to bathe and cushion the brain and spinal cord within their bony confines. The ventricular system consists of two large lateral ventricles in either cerebral hemisphere that extend into the temporal lobes (temporal horns) and occipital lobes (occipital horns). The lateral ventricles connect with the third ventricle via the interventricular foraminae (foramen of Monro). From the third ventricle, the CSF flows into the fourth ventricle, after passing through a thin canal located in the dorsal brainstem (cerebral aqueduct). CSF exits the fourth ventricle and enters the subarachnoid space through foramen of Luschka and foramen of Magendie. The subarachnoid space, which is filled with CSF, surrounds the spinal cord, brainstem, cerebellum and cerebral cortex. CSF is produced by the choroid plexus within the ventricles themselves and is reabsorbed into the venous system in the subarachnoid space between brain and skull. It passes through arachnoid granulations into the superior sagittal venous sinus ¹. 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.

Interestingly, scientific study of CAT scans 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 biological in origin and led to a reinvigoration of the study of such conditions via modern scientific techniques.

more information: Your 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 spine. For further protection, the brain and spinal cord float in a sea of cerebrospinal fluid within the skull and spine. This cushioning fluid is produced by the choroid plexus tissue, which is located within the brain, and flows through a series of cavities (ventricles) out of the brain and down along the spinal cord. The cerebrospinal fluid is kept separate from the blood supply by the blood-brain barrier.

• Note 1: Purves D, Augustine GJ, Fitzpatrick D, Hall WC, Lamantia AS, McNamara JO, Williams SM, Neuroscience (third edition). Sinauer Associates Inc, July 2004. ISBN: 0878937250