The Meninges

The Meninges 3 layers:

• The Dura Mater• The Arachnoid• The Pia Mater

Specialized membranes that provide:• physical stability and shock absorption to the brain

• structural support to large blood vessels that supply the CNS

Dura mater

• Double-layered external covering Top layer attaches to the inner surface of the skull (periosteum)

Meningeal layer—outer covering of the brain

• Folds inward in several areas (dural folds)

The ArachnoidSeparated from the dura mater by the subdural space.

• web-like

The web houses pockets of cerebrospinal fluid

Shock absorber and transporter

The Pia Mater• Internal innermost layer• Clings to the surface of the brain

• Main function is circulation Highly vascular

Meninges

Cerebrospinal fluid:

CSF: clear, colorless fluid that

circulates around the brain

and spinal cord.

Functions protects the brain from damage against the skull provides a “bath” for the brain to float in,

decreasing its effective weight.

CSF

Grey vs White Matter White matter

• Is superficial

• Contains myelinated and unmyelinated axons Gray matter

• Surrounds central canal of spinal cord

• Contains neuron cell bodies, neuroglia,

unmyelinated axons

• Has projections (gray horns)