Topic 10: Protective Mechanism of Brain - Part 1

meninges

Protective layers of the brain that function to protect and stabilize the CNS

Includes: dura, arachnoid, and pia mater

dura mater

Meninges layer that is dense, thick, tough, and fibrous.

• attatched the inner surface of teh skull, overlies the archnoid mater

• Structures: falx cerebri, tentorium cerbelli, falx cerebelli

falx cerebri

Structure of the dura mater: longitudinal, separates cerebrum

• acts as a protective layer around the cerebrum

tentorium cerebelli

Structure of the dura mater that is located above the cerebrum, arises from the temporal bone and from the tentorial notch

• separates cerebrum from cerebellum and brainstem

falx cerebelli

Structure of the dura mater that separates the cerebellar hemispheres

epidural space

Potential space around the dura mater that is in between the dura and the bone

subdural space

Potential space around the dura mater that is between the dura and the arachnoid

hematoma

A rupture of a blood vessel inside the head

arachnoid mater

The middle meningeal layer, thin spiderweb-like

• Structure: arachnoid trabecula, arachnoid granulations

• located above subarachnoid space

arachnoid trabecula

Structure of the arachnoid mater that is a fibrous, elastic connective tissue

• Function: maintains subarachnoid space and allows for cerebrospinal fluid to occupy the space

arachnoid granulations

Structure of the arachnoid mater (called “villi”) function to drain cerebrospinal fluid from the subarachnoid space

subarachnoid space

Layer of space located between arachnoid and pia mater

• contains arachnoid trabecula (to maintain space) and cerebrospinal fluid

• part of the venous system (large blood vessels)

• encloses the entire CNS

pia mater

Layer of the meninges that is thin, transparent, delicate, and vascular

• Layer adheres to entire brain surface (like leggings)

• Layer in which choroid plexus is formed

choroid plexus

Network of vascular capillaries (small, numerous blood vessels)

• Located mostly in lateral ventricles and 4th ventricle

• Formed in Pia Mater

• Produces: cerebral spinal fluid, works to turn Blood —— CSF

middle meningeal artery

Largest artery in the CNS, most likely to hemorrhage - supply blood to meninges

meningeal veins

Veins within the superior sagittal sinus - supply blood to meninges

meningitis

Inflammation of the meninges - 2 types

1. Viral - mild, common, quick recovery

2. Bacterial - severe, possible brain damage, potentially life-threatening