What are the three layers of tough elastic tissue that enclose the brain and spinal cord called?

The three layers of tough elastic tissue that protect and enclose the brain and spinal cord are collectively known as the meninges. This protective structure consists of three membranes: the dura mater, arachnoid mater, and pia mater. The dura mater is the outermost layer, providing a tough protective barrier; the arachnoid mater is the middle layer, which has a web-like structure; and the pia mater is the innermost layer that closely adheres to the brain and spinal cord, providing support and housing blood vessels.

In the context of the question, the meninges serve critical functions, including protecting the central nervous system from injury and providing a supportive environment for the blood vessels that supply the brain and spinal cord. Understanding these protective layers is fundamental in biology and medicine as they play essential roles in maintaining the health and functionality of the central nervous system.