Final answer:
Cerebrospinal fluid is manufactured in the ventricles of the brain by the choroid plexus and ependymal cells. It circulates through the ventricular system and enters the subarachnoid space.
Step-by-step explanation:
Cerebrospinal fluid is manufactured in the ventricles of the brain. The choroid plexus, which is a specialized membrane, produces CSF within the ventricles. Ependymal cells filter the blood to create CSF, which is a clear solution containing water, small molecules, electrolytes, and dissolved oxygen and carbon dioxide. The CSF then circulates through the ventricular system and enters the subarachnoid space through apertures.