L21 Flashcards
Function of meninges
Protective covering for brain
What are the 3 layers of the meninges
From outer to inner:
-Dura Mater
-Arachnoid
-Pia mater
DAP
Features of dura mater (5)
-Outermost layer
-Most protective (dense and fibrous
-has 2 layers (outer and inner)
-Space between forms venous sinuses
Inner layer forms dural folds
What are the features of dural folds?
-formed by inner layer of dura mater
-seperate major divisions of brain
-provide stability of brain within cranium
What are the 3 Dural Folds
-Falx Cerebri
-Falx Cerebelli
-Tentorium Cerebelli
What is the Falx Cerebri
-Seperates cerebral hemispheres
-in median plane
-sickle shaped
Falx cerebelli
-Seperates cerebellar hemispheres
-in mediane plane
Tentorium Cerebelli
-Seperates the cerebrum from cerebellum
-Horizontal plane
Name the folds
-Falx cerebri
-Tentorium cerebelli
-Falx cerebelli
Features of venous sinus
-Located between inner and outer layer of dura mater
-Veins (areas) which collect venous blood (deoxygenated blood) and ‘old’ CSF (depleted nutrients) after ventricular circulation.
Arachnoid
-Layer beneath dura mater
-spider web like appearance
Arachnoid features
-does not extend into sulci of brain (valleys)
-Contains subarachnoid space and arachnoid granulations
-Contains blood vessels within the subarachnoid space
How does the Subarachnoid space look like?
Like the legs which hold up a pier
What is the subarachnoid space filled with and its function
Cerebrospinal fluid which when filled will act for protection against impacts
what does the arachnoid granulations do?
-transports old CSF into venous sinous through the Inner layer of dura mater
Features of Pia Mater
-Thin, transparent and delicate
-Blood vessels sit atop of pia mater
-Adheres to brain and follows gyri (hills) and extends into sulci (furrows)
The spinal cord also has meninges, name them
-Dorsal root ganglion
-Pia mater
-Arachnoid mater
-Dura mater
-Spinous process of vertebra
The meningeal sac around the spinal cord is an extension of subarachnoid space
What is the ventricular system?
-Network of interconnected ‘spaces’ (ventricles) within the brain
-Filled with CSF which provides nutrients and protection to brain
-Inside ventricles are lines with ependymal cells
-CSF is produced by Choroid plexus
What is the ventricular system made up of?
-2 lateral ventricles
-Third ventricle
-Cerebral aquaduct
-Fourth ventricle
Central Canal (spinal cord)
Name the ventricles
-2 lateral ventricles
-Third ventricle
-Cerebral aquaduct
-Fourth ventricle
Central Canal (spinal cord)
Features of lateral ventricles
-Two of them
-One in each cerebral hemisphere
Where is third ventricle located/associated with?
Located in diencephalon
Function of cerebral aquaduct and located in?
-Connects 3rd and 4th ventricle
-located in midbrain
Where is fourth ventricle located?
-Located at the level of the cerebellum
Where is Central Canal? (still part of ventricular system)
-Within the central canal of the spinal cord
Features of CSF
-Produced by choroid plexus within ventricles
-Surrounds CNS within subarachnoid space
-provides support and cushion
-transports nutrients and waste
What is the CSF circulation path?
Start: -Lateral ventricle
- 3rd ventricle
-cerebral aquaduct
-4th ventricle
-subarachnoid space
Within the subarachnoid space it flows around the brain and spinal cord
Exit: through arachnoid granulations into venous sinus