The ventricles of the brain are interconnected, fluid-filled cavities within the brain that produce and circulate cerebrospinal fluid (CSF).
There are four ventricles in total:
1. Two lateral ventricles (one in each hemisphere):
These C-shaped ventricles are the largest and are located in the cerebral hemispheres.
Each lateral ventricle has a central body and three extensions, called horns (anterior, posterior, and inferior).
2. Third ventricle:
A narrow, slit-like cavity located in the midline of the brain, between the two thalami.
It connects to the lateral ventricles through the interventricular foramen (also known as the foramen of Monro).
3. Fourth ventricle:
A tent-shaped cavity located between the cerebellum and the brainstem.
It connects to the third ventricle through the cerebral aqueduct (also known as the aqueduct of Sylvius).
Cerebrospinal fluid (CSF) is a clear, colorless fluid produced primarily by the choroid plexus, a network of blood vessels and specialized cells found within the ventricles.
The choroid plexus filters blood plasma and secretes CSF, which has several important functions:
1. Buoyancy:
CSF provides a cushioning effect that reduces the effective weight of the brain and spinal cord, protecting them from physical injury.
2. Protection:
The fluid acts as a shock absorber, protecting the delicate neural tissues from sudden movements or impacts.
3. Chemical stability:
CSF helps maintain a stable chemical environment by regulating ion concentrations, buffering changes in pH, and removing waste products.
4. Nutrient and waste transport:
CSF aids in the exchange of nutrients and waste products between the blood and the nervous tissue.
CSF is produced in the ventricles, circulates through the ventricular system, and then flows into the subarachnoid space surrounding the brain and spinal cord. From there, it is eventually reabsorbed into the bloodstream through arachnoid granulations, which are specialized structures that project into the venous sinuses.
This continuous production, circulation, and reabsorption of CSF help maintain the proper environment for the central nervous system to function optimally.