Ependyma

The mammalian brain is a tube filled by cerebrospinal fluid, which is mainly secreted by the choroid plexus and plays major roles in brain development, homeostasis, and repair. Polarized multiciliated ependymal cells line the ventricular cavities of the brain. Bundles of motile cilia protrude into the ventricles where their coordinated beating is required for normal cerebrospinal fluid outflow. Recent advances in the understanding of the mechanisms underlying the development of ependymal cells are reviewed, and their known functions under normal and pathological conditions are also discussed.