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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
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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 Arachnoid Separated 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
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.
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)