Final answer:
The central canal and the subarachnoid space contain cerebrospinal fluid (CSF), which provides protection, nutritional support, and waste removal for the central nervous system. CSF acts as a liquid cushion, protecting the brain and spinal cord from injury and facilitating the exchange of nutrients and waste substances.
Step-by-step explanation:
The central canal and the subarachnoid space play critical roles in the functioning and protection of the brain and spinal cord, part of the central nervous system (CNS). These spaces are filled with cerebrospinal fluid (CSF), which provides essential protection, support, and helps in the circulation of chemical substances.
CSF acts as a liquid cushion for the brain and spinal cord, absorbing shock and preventing injury to these vital structures. It also serves to nourish the CNS by circulating nutrients and removing metabolic wastes. The CSF within the subarachnoid space provides a thin buffer to protect the brain and spinal cord while allowing for the essential transfer of molecules between the blood and CNS, thanks to barriers like the blood-brain barrier.