The central nervous system (CNS) is made up of the brain and spinal cord, and consists of millions of specialized cells working together. Brain cells (neurons) are responsible for the transmission of information. They are surrounded by glial cells, which are much smaller and provide oxygen and nutrients to the neurons, in addition to removing dead cells. There are three different types of glial cells: astrocytes, oligodendrocytes, and ependymal cells.
Brain tumours that grow out of these cells are named, respectively: astrocytoma, oligodendroglia and ependymoma. Surrounding the brain tissue, there are three layers of tissue that serve as protection and produce the cerebrospinal fluid. These layers are collectively called the meninges and include the dura mater, arachnoid mater, and pia mater. These layers of tissue can also give rise to cancerous tumours of the CNS.
Information taken from Brain Tumour Foundation of Canada.