Meninges/Ventricles Flashcards
What are the 3 layers of meninges?
Dura mater
Arachnoid
Pia
What is the major function of the dura mater?
Mechanical strength
What is the major function of the arachnoid mater?
Barrier function, allows CSF circulation by selectively allowing components to pass through within “arachnoid villi”
What is the major function of the pia mater?
Barrier function, closely lines external surface of the brain, abuts against astrocyte foot processes
What are the differences between spinal and cranial meninges?
There is an epidural space in the spine that does not normally exist in the skull. The spine contains thickened pia components (denticulate ligament, filum terminale) that anchor the cord within the spinal canal
Describe the flow of CSF from production to venous sinuses
- Produced in ventricles
- Flows lateral to 3rd to 4th and out the foramens of Magendie and Luschka
- Cisterns
- Tentorial notch
- Through arachnoid villi into venous sinuses
What are the components of the choroid plexus?
Fenestrated capillary
Pia
Choroid epithelium (Ependyma)
*These layers make up the blood-CSF barrier
What is the function of CSF?
Mechanical support (buoyancy)
Spatial buffering
Removal/Reabsorption of brain metabolites
Spread of hormones
What are circumventricular organs?
Chemosensitive areas (no BBB) of the brain that monitor concentrations of hormones in the blood and CSF ex: area postrema w/in 4th ventricle
Pair each ventricle with its corresponding brain region
Lateral ventricles: cerebral hemispheres
Third ventricle: diencephalon
Fourth ventricle: cerebellum/brainstem
What is the difference between a noncommunicating and a communicating hydrocephalus?
Noncommunicating = obstruction within ventricles Communicating= obstruction in subarachnoid space
