The
choroid plexus is a
plexus of
cells that produces the
cerebrospinal fluid in the
ventricles of the
brain. The choroid plexus consists of modified
ependymal cells. CSF is recycled (flushed) 4 times per day in order to clean out metabolites and toxins like
beta amyloid. Hence the choroid plexus must produce about 500 milliliters of CSF daily (or 21 mL per hour).