Glial cells are found in the nervous system. They surround neurones and contribute to the control of the chemical and electrical environment by providing them with nutrients and removing their waste. For example, these cells produce myelin, a substance which is used to insulate nerve fibres (one thing that deterioration in the production of myelin causes is multiple sclerosis) and allows electrical signals to be transmitted faster.
There are two types of glial cells:
- the macroglial cell which includes cells such as astrocytes and oligodendrocytes ;
- and the microglial cells which consist of macrophages.
There are approximately as many glial cells a there are neurones in our nervous system, approximately 100 billion.
Glial cell seen on Golgi staining microscope. © Diberri, Wikipedia DP