Inside the head a fluid called cerebrospinal fluid (CSF) surrounds the brain and fills the space known as the ventricular system. Essentially, the brain and the spinal cord "float" in the CSF, which acts like a buffer for the cortex and protects the brain from physical injuries.
The choroid plexus, a vascularised structure that is located in the lateral brain ventricles, produces CSF about a rate of 500 ml/day.
The CSF circulates from the lateral ventricles into the third ventricle, then by passing the cerebral aqueduct, to the fourth ventricle and into the subarachnoid space. The CSF flows finally to the spinal cord.
The CSF has many different functions: the mechanical protection of the brain, the regulation of the intracranial pressure, keeping the brain tissue moist and finally the distribution of metabolites. The absorption of cerebrospinal fluid occurs in the arachnoid villi. The arachnoid membrane permits the uni-directional flow of CSF out into the venous blood. |
