CSF And Cerebral Blood Flow Flashcards
What is the meninges
The membranous coverings of brain and spinal cord
What are the 3 layers of the meninges
Dura mater
Arachnoid mater
Pia mater
What are the 2 major functions of the meninges
Supportive framework for cerebral and cranial vasculature
Acting with CSF to protect CNS from mechanical damage
What is the dura mater
The outermost layer of meninges directly underneath bones of skull and vertebral column
What are the 2 layered sheets of connective tissue in the dura mater
Periosteal layer
Meningeal layer
What is the periosteal layer
Lines inner surface of bones of cranium
What is the meningeal layer
Located deep to periosteal layer
Continuous with dura mater of spinal cord
What is located between the 2 layers of dura mater
Dural venous sinuses
What is dura mater innervated by
CNV (trigeminal)
Where does the dura mater receive its vascular supply from
Middle meningeal artery and vein
What is the dural venous sinuses responsible for
Venous drainage of cranium and empty into internal jugular veins
What are the 4 dural partitions
Falx cerebri
Tentorium cerebelli
Falx cerebelli
Diaphragma sellae
What does the falx cerebri do
Projects downwards to separate right and left cerebral hemispheres
What does the tentorium cerebelli do
Separates occipital lobes from cerebellum contains space for passage of brain - tentorial notch
What does the falx cerebelli do
Separates right and left cerebella hemispheres
What does the diaphragma sellae do
Covers hypophysial fossa of sphenoid bone contains small opening for passage of stalk of pituitary gland
What is the arachnoid mater
Middle layer of meninges lying directly underneath dura mater
What is underneath arachnoid mater
Space which is known as sub arachnoid space which contains CSF acting as a cushion for the brain
What does arachnoid mater consist of
Layers of connective tissue it is avascular and does not receive any innervation
What are arachnoid granulations
Small projections of arachnoid mater into dura allowing CSF to re enter circulation via dural venous sinuses
Where is pia mater located
Underneath sub arachnoid space
How does the pia mater appear
Very thin tightly adhered to surface of brain and spinal cord
Highly vascularised with blood vessels perforating through membrane
How many dural venous sinuses are there
11 in total
Where is the straight, superior and inferior sagittal sinuses found
In falx cerebri of dura mater
Which sinus is a continuation of the great cerebral vein and inferior sagittal sinus
Straight sinus
What does the cavernous sinus do
Drains ophthalmic veins and can be found on either side of sella turcica
How does blood return to the internal jugular vein
Via superior or inferior petrosal sinuses
What are the 6 structures that the cavernous sinus receives venous drainage from
Facial veins
Ophthalmic veins
Superficial middle cerebral vein
Sphenoparietal sinus
Central vein of retina
Pterygoid plexus
What 3 structures travel through lateral wall of cavernous sinus
Oculomotor nerve
Trochlear nerve
Ophthalmic and maxillary branches of trigeminal nerve
What 3 structures travel through the cavernous sinus
Abducens nerve
Carotid plexus (post ganglionic sympathetic nerve fibres)
Internal carotid artery (cavernous portion)
What nerve is most commonly affected by cavernous sinus thrombosis
Abducens nerve
What secretes CSF
Choroid plexus found in roof of ventricles derived from blood plasma but lower in protein
What are the 5 functions of the CSF
Protection
Buoyancy
Chemical stability
Homeostasis
Cleaning waste
Which has a higher protein content CSF or blood
Blood
What is the ventricular system
Structures that produce CSF and transport it around the cranial cavity
What is the ventricular system lined with
Ependymal cells which form choroid plexus
What are the 4 ventricles in the ventricular system
Right and left lateral ventricles
Third and fourth ventricles
What is the foramen of monro
Where the lateral ventricles connect to the third ventricle
What are the 2 protrusions on the anterior surface of the third ventricle
Supra optic recess
Infundibular recess
What are the 2 places that the fourth ventricle drains into
Central spinal cord
Subarachnoid cisterns
What does the choroid plexus consist of
Capillaries and loose connective tissue surrounded by cuboidal epithelial cells
How is plasma filtered from blood
By epithelial cells to produce CSF
What are zonula occludens
Provide structural support to endothelial wall, circumscribe cells and provide seal with all adjacent cells
What are zonula adherens
Connects adjacent cells
What are astrocytes
Highly branched cells with small bodies found both in white and grey matter
What are the 2 paired arteries responsible for the blood supply to the brain
Vertebral
Internal carotid arteries
What is the circle of Willis
The terminal branches of the arterial supply to the brain form an anastomotic circle
Where do the internal carotid arteries originate from
At bifurcation of left and right common carotid arteries at level of 4th cervical vertebrae
Where do the right and left vertebral arteries arise from
Subclavian arteries, medial to anterior scalene muscle
What are the 3 main constituents of the circle of Willis
Anterior cerebral arteries
Internal carotid arteries
Posterior cerebral arteries
