Meninges and ventricular system Flashcards
What are the three layers of meninges ?
Dura mater
Arachnoid
Pia mater
What is dura mater?
Outer most layer of meninges that is dense and fibrous
Sits directly below cranium bone to prevent damage to brain
Two layers (outer and inner)
Space between the layers forms venous sinuses
Inner layer forms dural folds
What are dural folds?
Formed from inner layer of dura mater which act to stabilise the brain
Seperate major divisions of the brain
Three different types - falx cerebri, falx cerebelli and tentorium cerebelli
What is the falx cerebri?
Found in the cerebrum, separates cerebral hemispheres, on the median plane
What is the falx cerebelli?
Found in the cerebellum, separates cerebellar hemispheres, found on the median plane
What is the tentorium cerebelli?
Separates the cerebrum from the cerebellum, horizontal plane, at right angles to falx cerebri and cerebelli
What is the venous sinus?
Found in dura mater layer, located where the two layer seperate
Collecting veins that collects liquid- venous blood form brain (deoxygenated blood) and old CSF after it has cycled
What is the arachnoid layer?
Layer beneath dura mater, layer above pia mater, does not extend into sulci, contains subarachnoid space and arachnoid granulations, contains blood vessels
What is the subarachnoid space?
Found between the arachnoid and pia mater layer, filled with CSF
What are arachnoid granulations?
Perforate the inner layer of dura mater, transport old CSF from subarachnoid space into venous sinus
What is pia mater?
Inner most 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
Four features of the ventricular system
- Network of interconnected spaces within brain
- Filled with CSF with nourishes and protects brain
- Spaces lined with ependymal cells which circulate CSF
- CSF is produced by choroid plexus
Ventricles in the ventricular system
Lateral ventricles (2), one in each cerebral hemisphere
Third ventricle (1), located in diencephalon
Cerebral aqueduct (1), connects 3rd ventricle to 4th, in midbrain
Fourth ventricle (1), located at the level of the cerebellum
Central canal (spinal cord)
Four features of CSF
- Produced by choroid plexus within the ventricles
- Surrounds the CNS within subarachnoid space
- Provides support and cushion
- Transports nutrients and waste
Circulation path of CSF
Starts at lateral ventricles, within subarachnoid space it flows around brain and spinal cord, exits through arachnoid granulations
