Name the three layers of meninges.

The three layers of meninges, which are the protective membranes that surround the brain and spinal cord, are as follows:

Dura mater: This is the outermost layer and is the toughest and thickest of the three meningeal layers. It serves as a protective barrier and helps contain the cerebrospinal fluid (CSF).

Arachnoid mater: The arachnoid mater is the middle layer and is named for its spider-web-like appearance. It lies beneath the dura mater and is separated from the innermost layer, the pia mater, by the subarachnoid space. Cerebrospinal fluid flows within this subarachnoid space.

Pia mater: The pia mater is the innermost layer of the meninges and is in direct contact with the brain and spinal cord. It is a delicate and thin membrane that follows the contours of the brain and spinal cord, providing support and nourishment to these structures.

Together, these three layers provide protection, support, and a cushioning effect for the central nervous system.