What is cerebrospinal fluid and what is it made of?

Cerebrospinal fluid is the fluid that is found around the brain and spinal cord. Fluid is made up of a group of cells called the choroid plexus, which are located deep in the brain. The human body has about 150 milliliters of cerebrospinal fluid – about two-thirds of a cup.
As this colorless fluid travels around the brain and spinal cord, it flattens the organs, draws off the necessary reserves from the blood and gets rid of waste products from the brain cells.