Describe the protective covering of the brain and spinal cord.

The brain and spinal cord are the central organs of the nervous system, and they are protected by special coverings known as the meninges. These coverings provide both mechanical protection and nourishment to the delicate nervous tissue.

The meninges consist of three distinct layers:

1. Dura mater – This is the outermost, thick, and tough layer. It forms a strong protective shield around the brain and spinal cord, preventing physical shocks and injuries.
2. Arachnoid mater – Located beneath the dura mater, this is a thin, web-like membrane. Between the arachnoid and pia mater lies the subarachnoid space, which is filled with cerebrospinal fluid (CSF). This fluid cushions the brain and spinal cord, reducing the impact of sudden jolts and maintaining chemical stability.
3. Pia mater – This is the innermost, delicate layer that closely adheres to the surface of the brain and spinal cord, following every fold and groove. It contains blood vessels that supply oxygen and nutrients to the nervous tissue.

Together, these three layers—dura mater, arachnoid mater, and pia mater—form the protective covering of the brain and spinal cord, ensuring both physical safety and metabolic support.