Final answer:
The subarachnoid space is filled with cerebrospinal fluid (CSF), a clear fluid that provides cushion and protection for the brain and spinal cord. It is produced within the ventricles by ependymal cells in the choroid plexus and serves multiple functions including nutrient distribution and waste removal.
Step-by-step explanation:
The subarachnoid space is filled with cerebrospinal fluid (CSF).
CSF is a clear bodily fluid that cushions the brain and spinal cord within the central nervous system (CNS), providing mechanical and immunological protection. This protective layer is produced by ependymal cells in the choroid plexus, which filter blood to create CSF. The fluid circulates through the ventricles of the brain, around the CNS, and is reabsorbed into the bloodstream. An imbalance in its production or reabsorption can lead to conditions like hydrocephalus, indicating the critical role CSF plays in brain health.
CSF is not only a cushion but also serves to circulate nutrients and remove waste from the CNS, aiding in maintaining the delicate environment required for proper nervous system function. Oxygen and carbon dioxide are among the components dissolved in CSF, similar to their dissolution in blood, allowing for essential gas exchange.