There are four ventricles in the brain, these include: two lateral ventricles, third ventricle, and fourth ventricle. These ventricles are lined by ciliated ependymal cells, and are filled with cerebrospinal fluid. The capillary network present within each ventricle is called the choroid plexus. The choroid plexus forms the cerebrospinal fluid from the blood plasma.
Over the years, ventricles were believed to pump the fluid through the nerves that enables movement and sensation of the muscles and sensations of the limbs.
However, the ventricles primarily function to produce and circulate the cerebrospinal fluid. This fluid provides protection to the brain from mechanical injuries and allows circulation of neurotransmitters. The neurotransmitters are the chemicals that facilitate transmission of nerve impulses between the neurons (specialized cells of the nervous system) and between neurons and target cells, thereby enabling movement and sensation of the limbs as well as other body structures.
The left and right lateral ventricles are present in the left and right hemispheres of the cerebrum. They are horn-shaped, or inverted C-shaped which project into the frontal, occipital, and temporal lobes of the cerebrum. The foramen of Monro connects the two lateral ventricles to the third ventricle which is located in between the left and right thalamus. The fourth ventricle is present in the brainstem, and is connected with the third ventricle through the cerebral aqueduct.
The hollow spaces present in the brain, filled with fluid, are called brain ventricles. It was believed that the fluid present in the ventricles were forced out and moved through the nerves, and caused the movement of the muscles and limbs. The nerves were believed to be hollow tubes that helped in the movement of the fluid from the brain to the muscles. Thus the main function of the brain ventricle was to provide sensation and limb movement, which was mainly caused by the movement of fluid present in the ventricles through the nerves.