Lecture 21: Meninges and ventricular system Flashcards
What are meninges
Protective covering for the brain
What are the 3 layers of meninges
Dura mater, Arachnoid, Pia mater
What are the five features of the Dura mater
Outer most layer of meninges
Dense and fibrous (tough)
Two layers (inner/outer)
Space between layers forms venous sinuses
Inner layer forms dural folds
What are the dural folds
Folds of the inner layer of the dura mater
What are venous sinuses
Spaces between the inner and outer layer of the dura mater
What are the three features of the dura maters dural folds
Formed from the inner layer of dura mater
seperate major divisions of brain
provide stability of the brain within cranium
What are the 3 dural folds
Flax cerebri
Flax cerebelli
Tentorium cerebelli
Where is the flax cerebri and what is its function
It is one of the Dural folds
Separates cerebral hemispheres
median plane
Where is the flax cerebelli and what is its function
It is one of the Dural folds
Separates cerebral hemispheres
median plane
What is the Tentorium cerebelli
It is one of the Dural folds
separates the cerebrum from the cerebellum
horizontal plane
What are 3 features of the Dura maters Venous sinus
Located where the two layers of dura mater seperate
Collecting veins
They collect 2 things:
- Venous blood from the brain
‘Old’ CSF after it has cycled through the ventricular system
Where is the arachnoid layer found
It is the layer just under the dura mater
What are the Five Features of the Arachnoid
Layer beneath the dura mater
Layer above pia mater
Does not extend into sulci (valleys)
Contains blodd vessels within the sub arachnoid space lying on top of pia mater
Contains 3 special features
i. Subarachnoid space
ii. Arachnoid granulations
iii. Arachnoid Trabeculae
What is the subarachnoid space
It is the space between the arachnoid and pia mater, it is filled with CSF
What are arachnoid granulations
Perforate the inner layer of dura mater
Transport “old” CSF from
subarachnoid space into
venous sinus
What are the Four features of the pia mater
Inner layer of meninges
Transparent and delicate
Blood vessels in arachnoid sit on top of pia mater
Adheres to brain and follows gyri and extends into sulci
What are the Four Features of the Ventricular System
Network of interconnected “spaces” (= ventricles) within the brain
Filled with CSF
Spaces lined with ependymal cells which circulate the CSF (waiving cilla)
CSF is produced by the choroid plexus
What are the 4 features of CSF and its circulation
Produced by Choroid plexus within the ventricles
Surrounds CNS within subarachnoid space
Provides support and cushion
Transports nutrients and waste
What are the parts of the ventricular system
Lateral ventricles (2)
Third ventricle
Cerebral aqueduct
Fourth ventricle
Centrical canal (spinal cord)
Where is the third ventricle located
In the diencephalon
Where is the cerebral aqueduct located
in the midbrain
Where is the Fourth Ventricle located
at the level of the cerebellum
Where are the lateral ventricles located
One in each cerebral hemisphere
What is the circulation path of the CSF
Lateral ventricles
3rd Ventricle
Cerebral aqueduct
4th Ventricle
Subarachnoid space
Within subarachnoid space it flows around brain and spinal cord
What are the functions of the Cerebrospinal fluid
Ultrafiltrate of plasma
Provides protection and cushioning for brain
Nourishment (vitamins, necessary ions)
Hormones from blood (Leptin, Prolactin)
Removal of metabolic waste (eg. from neurotransmitter metabolism)
Removal of foreign particles
Usually considered sterile, can contain microbes in infection
Cerebrospinal fluid (CSF) circulates around the brain in which layer of the meninges?
Arachnoid
Old/used CSF is transported into the venous circulation through which structure?
Arachnoid gradulations
