Brain lining. Coloured scanning electron micrograph (SEM) of the lining of the brain, showing the ciliary hairs of ependymal cells. Ependymal cells are a type of neuroglia (glial cells) that line the ventricles of the brain and produce cerebrospinal fluid (CSF). CSF has a number of functions, including buffering the brain from shock, transporting hormones around the brain and absorbing waste products. The ciliary hairs are used to help circulate the CSF. Magnification: x800 when printed 10 centimetres wide.