Where is the cerebrospinal fluid produced?

Cerebrospinal fluid is produced by modified epithelial cells in the thin membrane that lines the ventricular system of the brain and the spinal cord. These modified epithelial cells are named the ependyma. Each of the cerebral ventricles has an associated choroid plexus (http://en.wikipedia.org/wiki/Ventricular_system) which produce and secrete cerebrospinal fluid. The cerebral ventricles are interconnected spaces within the brain that permit the fluid to circulate in a specific manner. (see http:/www.answers.com/topic/cerebrospinal-fluid?cat=health for an excellent diagram).