Meninges (Quiz 4) Flashcards
________ is an essential interstitial nutrient source, but when surrounding the brain acts as a shock absorber and “floats” the brain in water and it will be cushioned
CSF
The ____________ are 3 isolated layers that protect, cushion, provide a passageway for CSF, biochemically isolate neurons, keep sodium and potassium levels constant. The brain is mechanically suspended within the meninges
meninges
The dense fibrous tissue of the cranial dura mater supports the brain and acts as the lining layer of the cranial bones. It is also called pachymeninx. The cranial dura is thick and includes an ______________ layer and an _______________ layer
internal meningeal (attached to the arachnoid mater), external endosteal
The epidural space is between the dura mater and calvaria. Is the epidural space an actual space or potential space?
potential space
**following a trauma, blood may enter this “potential space” and accumulate forming an epidural hematoma (blood comes from ruptured meningeal a. or less commonly a torn dural venous sinuous)
The cranial dura is continuous at the _________________ with the spinal dura mater
foramen magnum
T/F: the subdural space in the cranial region is absent, but present in spinal region
true!
The cranial subdural space is in the innermost dural layer, near the dura-arachnoid interface. Is the subdural space an actual or potential space?
potential space
Is the subarachnoid space an actual space or potential space?
actual space, its filled with CSF and is usually enlarged in the cisterns
Which meningeal layer is tightly attached to the brain?
pia mater
There are locations where the inner dural layer separates from the external layer and projects into the cranial cavity. These extensions of dura reflect back on themselves to form double layer….
dural folds
What are the 4 main dural folds?
test q
1) falx cerebri
2) tentorium cerebelli
3) falx cerebelli
4) diaphragma sellae
Where is the falx cerebri found?
test q
between the cerebral hemispheres (within longitudinal fissure)
Where is tentorium cerebelli found?
test q
over the cerebellum, between it and the cerebrum
Where is falx cerebelli found?
test q
between the cerebellar hemispheres
Where is diaphragma sellae found?
test q
-covers the pituitary gland
-allows infundibulum through
There are no receptors for pain in the brain- at least no nociception is perceived. Neurosurgery can be performed without general anesthesia. The dura has sensory innervation from the ___________. Meningeal blood vessels are associated with these neurons. Headaches can be associated with dural sinus deformation/compression
trigeminal n.
At the attached edges of dural folds the 2 cranial dura are separated to form venous channels called….
dural sinuses
Where is the superior sagittal sinus found?
test q
attached at the edge of the falx cerebri
Where are the L/R transverse sinuses found?
test q
along posterior line of attachment of the tentorium cerebelli
Where is the straight sinus found?
test q
between cerebral falx and tentorium cerebelli
All 4 of the dural sinuses meet in the _____________ of the sinuses near the internal occipital protuberance
confluence (swelling)
Venous blood flows posteriorly in the superior sagittal and straight sinuses into the confluence, and from there through the transverse sinuses. Each transverse sinus continues, as the sigmoid sinus, which proceeds anteriorly and inferiorly through an S-shaped course and empties into the….
internal jugular v.
Dural sinuses are roughly triangular in cross section and are lined with….
endothelium
Sinuses are venous channels found between the endosteal and meningeal layers of _____ mater in the brain. They drain blood from the cortex, the meninges, and the scalp and deliver it to the internal jugular veins
dura
The cranial arachnoid consists of an outer part which is several layers of cells that adheres to the inner cellular layer of the dura- the arachnoid barrier layer, and in inner part, the arachnoid trabeculae. The arachnoid is a thin, avascular membrane composed of a few layers of cells interspersed with bundles of ________
collagen
Small strands of collagenous CT called _________________, covered with fibroblast like arachnoid cells, extend to the pia. This bridge across the subarachnoid space gives it a spider web like appearance
arachnoid trabeculae
Arachnoid trabeculae help keep the brain suspended within the….
meninges
In the meshes of the arachnoid trabeculae (subarachnoid space), CSF circulates. Although the arachnoid dips into the __________________, it does not dip into the individual sulci of hemispheres
longitudinal cerebral fissure
Large subarachnoid regions contain a considerable volume of CSF, are called…..
subarachnoid cisterns
What are the 4 main cisterns?
test q
1) cerebellomedullary cistern also known as cisterna magna
2) pontine cistern
3) interpeduncular cistern
4) superior cistern also known as quadrigeminal cistern
Arachnoid trabeculae are particularly prominent in….
subarachnoid cisterns
The CSF contained in the subarachnoid space is separated from venous blood. At many locations along dural sinuses, like along the superior sagittal sinus, small evaginations of the arachnoid, called ______________, herniate through the wall of the sinus. Here only a loose layer of arachnoid cells and a layer of endothelium between subarachnoid space and venous blood. Large clusters of arachnoid villi are called ______________ (lots of villi here)
arachnoid villi, arachnoid granulations
Arachnoid villi are especially numerous in laterally directed dilations of the superior sagittal sinus, called….
venous lacunae or lateral lacunae
Arachnoid villi are the major sites of reabsorption of _______ into the venous system. They work like one way valves (similar to lymphatic capillaries), allowing flow from the subarachnoid space into the venous blood but not in the reverse direction
CSF
Pia mater is held in place by what glial cells?
astrocytes
The cranial _____ mater is the thinnest and most delicate layer of the cranial meninges. It closely follows every convolution on the brain surface and enters every cerebral sulcus. This mater follows ALL of the contours of the brainstem and all of the folds of the cerebral and cerebellar cortices
pia
The arachnoid and pia mater are continuous with each other, often regarded as 2 parts of a single layer, and so are sometimes referred to together as the…..
leptomeninges
