Cilia are minute, har-like processes on the surface of protozoans or of metazoans cells, which by their motion accomplish locomotion or produce a current. Each cilium contains a peripheral circle of nine doublet microtubules arranged around two single microtubules. Each microtubule is composed of tubulin proteins. Although the mechanism of ciliary movement is not completely under stood. It is known that the microtubules behave as sliding filament that move past one another much like the sliding filaments of vertebrate skeletal muscle. The fluxes of Ca2+ across the membrane is not responsible for controlling the organized beating of cilia.