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Cilia and flagella are hair-like outgrowths of the cell membrane. Clia are smaller structures while the flagella are longer. They are formed basal bodies which are centriole-like structures. Both help in movement of cell. The cilium and flagellum are covered with plasma membrane. They have a core called axoneme which has nine pairs of doublets of radially arranged peripheral microtubules and a pair of centrally located microtubules. This arrangement of microtubules is called 9+2 array. The central tubules are covered by a sheath and are connected to each other. The sheath is connected to one of the tubules of the peripheral doublet by a radial spoke. There ate nine radial spokes in total. The linkers connect the doublets to each other.