Total amount of CNS in CSF ?

Ans. is 'a' i.e., 100-150 mlThe major source of CSF is the choroidal plexus of all 4 ventricles, mainly in two lateral ventricles.Other sources of CSF are ependymal cells of the ventricles and the brain itself, perivascular spaces.The total volume of CSF in an adult is about 125-150 ml.The rate of formation of CSF is about 500-550 ml/day. Thus the CSF is replaced 3-4 times every day.