Meninges Flashcards
purpose of meninges
protection to the brain
nervous tissue of the brain
soft and delicate
irreplaceable neurons can be injured or destroyed by even slight pressure
the brain is protected by
skull
surrounding membranes (meninges)
BBB
foramina w/in skull
has many foramina for nerves, blood vessels, and brain structures to pass through
foramen magnum
anterior cranial fossa
middle cranial fossa
posterior cranial fossa
anterior cranial fossa
frontal lobe
middle cranial fossa
temporal lobe
posterior cranial fossa
cerebellum and brainstem
meningeal membranes
cover and protect CNS structures
protect blood vessels and enclose venous sinuses
contain CSF
form partitions within the skull
from outside–>inside, meninge layers
dura mater
arachnoid membrane
pia mater
what is the dura mater
leathery
strongest of the meninges
what is special about the dura mater
is is a double layer where it surrounds the brain
2 layers of the dura mater
rough fibrillated outer surface
inner surface is smooth and lines by a layer of endothelium
outer layer
adheres to the inner surfaces of the bones
adhesions being most marked opposite the sutures and at the base of the skull
periosteal layer
periosteal layer
superficial
lines the inner surface of the skull
inner layer
meningeal layer
true external covering of the brain
the dural layers are
fused together except in certain areas
–> where they are enclose the blood filled dural sinuses
what do dural sinuses do
collect venous blood and direct it into the internal jugular veins of the neck
which dural layer is rich in blood supply
periosteal layer
which layer has no vasular supply
meningeal layer
arachnoid mater
thin
glistening connective tissue layer
what is special about the arachnoid layer
brain can be seen beneath the transparent arachnoid
what does the arachnoid mater create
loose brain covering over the surface of the cerebrum
subdural space
separates the dura mater from the arachnoid mater
narrow serous cavity
subarachnoid space
beneath arachnoid membrane
wide
what is the arachnoid mater composed of
single layer of flattened fibroblasts that form an epithelial sheath
arachnoid trabeculae
from the sheath
extend toward and attach to the external surface of pia mater
what is the subarachnoid space filled with
CSF
contains the largest blood vessels serving the brain
–> poorly protected
arachnoid villi
protrude through the overlying dura mater and into the dural sinuses overlying the superior aspect of the brain
where is CSF absorbed into
venous blood sinuses through valvelike villi
cisterns
when the subarachnoid space widens in a few areas to form larger CSF compartments
the subarachnoid space is in b/w
arachnoid mater and pia mater
arachnoid granulations
transports CSF manufactured by choroid plexuses of the ventricles of the brain into the vascular system
pia mater
delicate connective tissue
richly invested with tiny blood vessels
what is special about the pia mater
only membrane that clings tightly to the brain following its every convolution
meningitis
inflammation of the meningeal layers
what causes meningitis
bacterial or viral infection
can spread to the underlying nerve tissue
encephalitis
brain inflammation
