Meninges and Ventricular System Flashcards
What are the meninges?
A protective covering for the brain and spinal cord found between the cranium bone and the surface of the brain
How many layers of the meninges are there?
3
What are the 3 layers of the meninges?
Dura mater, arachnoid and pia mater
What is the dura mater?
The outer most layer of the meninges
How would the dura mater be described?
Dense and fibrous-tough
How many layers are there in the dura mater?
2- outer and inner
What is the space between the two dura mater layers?
The venous sinuses which are only found in some places
What does the inner layer of the dura mater form?
Dural olds
What is the dura mater important for?
If the cranium fractures and preventing bone shards from penetrating the brain
What are the dural folds formed from?
The inner layer of the dura mater
What do the dural folds do?
Separate the major divisions of the brain and provide stability of the brain within the cranium
What are the 3 dural folds?
Falx cerebri, falx cerebelli and tentorium cerebelli
What does the falx cerebri do?
Separate the cerebral hemispheres
What plane is the falx cerebri in?
The median plane
What does the falx cerebelli do?
Separate the cerebellar hemispheres
What plane is the falx cerebelli in?
The median plane
What does the tentorium cerebelli do?
Separate the cerebrum from the cerebelli
What plane is the tentorium cerebelli in?
The horizontal plane
Where is the venous sinus located?
Where the two layers of the dura mater separate?
What is the function of venous sinus?
To collect veins
What two things does the venous sinus collect?
Venous blood from the brain and ‘old’ CSF after it has cycled through the ventricular system
What is the arachnoid mater?
The layer beneath the dura mater and above the Pia mater
Why is the arachnoid mater named?
Because of its spider like appearance
Does the arachnoid mater extend into sulci (valleys)?
No
What are the two special features of the arachnoid mater?
Subarachnoid space and arachnoid granulations
What is contained in the arachnoid mater?
Blood vessels which are within the subarachnoid space and lying onto of the Pia mater
Where is the subarachnoid space?
Between the arachnoid and the Pia mater
What is the subarachnoid space filled with?
Cerebrospinal fluid and contains blood vessels
Where are then arachnoid granulations found?
Perforating the inner layer of the dura mater into the venous sinus
What do the arachnoid granulations do?
Transport old cerebrospinal fluid which has lost its nutrients and is full of waste from the subarachnoid space into the venous sinus
What is the Pia mater?
The inner layer of the meninges
How is the Pia mater described?
Transparent and delicate
What sits on top of the Pia mater?
Blood vessels in the arachnoid
What does the Pia mater do?
Adhere to the brain and follows gyri and extends into sulci separating the smaller sections of the brain
What is the ventricular system?
A network of interconnected spaces (ventricles) within the brain
What is the ventricular system filled with?
Cerebrospinal fluid which nourishes and protects the brain
What is the ventricles lined with?
Ependymal cells which circulate the CSF (moving cilia)
What is the CSF produced by?
The choroid plexus in the ventricles
Hoe many lateral ventricles are there?
2
Where are the lateral ventricles?
One is found in each cerebral hemisphere
Where is the third ventricle found?
In the diencephalon
What does the cerebral aqueduct do?
Connect the third ventricle to the fourth
Where is the cerebral aqueduct located?
In the midbrain
Where is the fourth ventricle located?
At the level of the cerebellum
What is found in the ventricular system?
Lateral ventricles (2), Third ventricle (1), cerebral aqueduct (1), fourth ventricle (1) and the central canal (spinal cord)
Where is the CSF found?
Surrounding the CNS within the subarachnoid space
What does the CSF do?
Provide support and cushion as well as transporting nutrients and waste
Where does the path of CSF circulation start?
At the lateral ventricles
What is the path of the CSF from the lateral ventricles?
3rd ventricle, cerebral aqueduct, 4th ventricle, subarachnoid space
What does the CSF do within the subarachnoid space?
Flows around the brain and spinal cord in both directions
Where does the CSF exit?
Through arachnoid granulations into the venous sinus
