Where is cerebrospinal fluid produced and how is it reabsorbed?

• A. Produced by pineal gland; reabsorbed by lymphatic vessels in the dura.
• B. Produced by choroid plexus in subarachnoid space; reabsorbed via arachnoid granulations into lymphatic vessels.
• C. Produced by choroid plexus in ventricles; circulates in ventricles and subarachnoid space; reabsorbed via arachnoid granulations into venous sinuses.
• D. Produced by ependymal cells; reabsorbed via cranial nerves.

Answer: (C)

Cerebrospinal fluid is produced by the choroid plexus located inside the brain’s ventricles. It then flows through the ventricular system into the subarachnoid space surrounding the brain and spinal cord. Reabsorption occurs through arachnoid granulations (arachnoid villi) that project into the dural venous sinuses, most notably the superior sagittal sinus, allowing CSF to drain back into the venous blood. This classical pathway keeps CSF volume and pressure in balance. The pineal gland does not produce CSF, ependymal cells mainly help move CSF rather than secrete it, and absorption via cranial nerves is not how CSF returns to the bloodstream. (While there are meningeal lymphatics described, the standard described route is absorption into venous sinuses.)