The Brain, Meninges + CSF Flashcards
What is the CNS covered by
Meninges: a layer of tissue physically separates the CNS from the rest of the body
3 layers that comprise the meninges
- Pia mater: adherent to the brain + dips down into the sulci
- Arachnoid mater: middle layer
- Dura mater: outermost + very tough layer
What is the CNS bathed in
The meninges bathe the CNS in Cerebro-Spinal Fluid (CSF)
Function of meninges + CSF
Cushions the brain + protects it from damage
What is the CSF produced by
Choroid plexus (special epithelium) lining the brain cavities
What are the properties of the blood plasma components secreted by the choroid plexus
- Lower in: proteins, cells + most ions than plasma
- Higher concentration of: sodium, chloride + magnesium ions
Where does the CSF circulate
Circulates through the ventricles within the brain before exiting onto the surface of the brain to bathe the brain + spinal cord
Where is the CSF reabsorbed
Reabsorbed at arachnoid granulations into the the venous circulation
What are ventricles
- Spaces or cavities within the brain
- Linked by aqueducts (passageways)
Function of ventricles
Allow CSF to circulate through the brain: on to the surface of the CNS or into the spinal cord