How is CSF produced?
In an active (ATP requiring) process.
Na pumped into subarachnoid space through Choroid Plexuses of ventricles
Water follows Na from the blood vessels into the ventricles
Where is most choroid plexus found?
- Roof of Temporal Horns of Lateral Ventricles
- Floor of Bodies of Lateral Ventricles
- Roof of Posterior 3rd Ventricle
- Roof of 4th ventricle
Through what foramen does CSF travel?
- Foramen of Monro from lateral to 3rd ventricles
- Foramen of Magendie from 4th ventricle to Spinal subarachnoid space (M is for midline)
- Foramina of Luschka from 4th ventricle to cranial subarachnoid space (L is for lateral)
How much CSF is produced in the brain?
An adult makes 450-600 CCs of CSF every day
But only maintains ~150CCs in the brain at any point (~25 of which is in the ventricles)
So production = resorption
Where is CSF reabsorped?
Through Arachnoid villi within arachnoid granulations along the dural venous sinuses (mainly the sup sagittal)
Unlike production this is entirely passive
How do arachnoid villi work?
A passive process that is a group of pressure-dependant valves
Driven by pressure gradient between ICP & CVP