Final answer:
The three meninges that line the cranium and spinal cord are the dura mater, arachnoid mater, and pia mater, which provide a protective enclosure for the brain and spinal cord.
Step-by-step explanation:
The meninges are three-layered membranes that protect and enclose the brain and spinal cord while maintaining a thin layer of cerebrospinal fluid for added cushioning. These layers include the dura mater, which is the tough and fibrous outer layer, the arachnoid mater, a web-like middle layer forming a sac around the CNS, and the pia mater, which is the delicate inner layer that closely covers the brain and spinal cord. These meningeal layers each have their individual functions. The dura mater serves as a durable, protective sheath over the entire CNS and is attached firmly to the cranium and vertebral column. The arachnoid mater contains trabeculae resembling a spider web in the subarachnoid space, which is filled with circulating cerebrospinal fluid. Finally, the pia mater wraps around the brain and follows its intricate contours, making direct contact with the CNS.