The structure that protects the brain and spinal cord is called the meninges, which consists of three protective membranes: the dura mater, arachnoid mater, and pia mater. These layers encase the central nervous system (CNS) and serve to shield it from physical trauma and infection. Additionally, the cerebrospinal fluid (CSF) circulates in the space between these membranes, providing further cushioning and nourishment. Together, these elements maintain the integrity and functionality of the CNS.