Glial cells

Abstract

The term “glia” describes the non-neuronal, electrically passive cells of the central nervous system, which were fi rst defi ned as a distinct cell type by Rudolph Virchow in 1856, and derive their name from the Greek for “glue” due to their presumed primary function as connective tissue. The term is misleading however, as it implies a single cell type when it in fact encompasses three cell classes: oligodendrocytes, astrocytes, and microglia. The origins and roles of these different glial classes are quite distinct, but they have collectively been viewed as supportive cells that maintain a healthy microenvironment favourable to neuronal function, and play structural and protective roles throughout development. This traditional conception is now giving way to an appreciation that glial cells play an active and dynamic role in neurophysiology, in addition to providing passive support. This chapter outlines the origins, anatomy and primary roles of the major glial cells in the cerebellum.