Meninges and CSF Flashcards
what is the CNS covered by?
meninges
what are meninges?
layer of tissue that physically separates the CNS from the rest of the body
what are the three layers that the meninges are made up of?
PIA matter, Arachnoid matter and Dura matter
what is PIA matter?
adherent to the brain itself and dips into the sulci of the brain
what is arachnoid matter?
it is in the middle
what is Dura matter?
it is the outermost and very tough layer
what is the CNS bathed in in the meninges?
the CSF
combination of CSF and meninges =
cushions the brain and protects it from damage
what is the CSF produced by?
a specialised epithelium called choroid plexus
what does the choroid plexus do?
it secretes components of the blood plasma into the ventricles (not the heart) producing a clear fluid that is lower in proteins, cells and most ions than plasma
what does the CSF have a high concentration of?
Mg2+, Cl-, and Na+
how does the CSF circulate?
through the ventricles within the brain before exiting onto the surface of the brain to bathe the brain and the spinal chord
where is CSF absorbed?
into the venous circulation at a specialised point called arachnoid granulations
what are the ventricles?
simple spaces or cavities within the brain linked by aqueducts
what is the flow of CSF?
lateral ventricles
intraventricular foramina
third ventricle
cerebral aqueduct
fourth ventricle
median lateral apertures
central canal
