Describe the microstructure of cilia and flagella.

(N/A) Cilia and flagella are hair-like outgrowths of the cell membrane.
Cilia are small structures that work like oars,causing the movement of either the cell or the surrounding fluid.
Flagella are comparatively longer and are responsible for cell movement. Prokaryotic bacteria also possess flagella,but these are structurally different from eukaryotic flagella.
The electron microscopic study of a cilium or flagellum shows that they are covered with a plasma membrane. Their core,called the axoneme,possesses a number of microtubules running parallel to the long axis.
The axoneme usually has nine pairs of doublets of radially arranged peripheral microtubules and a pair of centrally located microtubules. Such an arrangement of axonemal microtubules is referred to as the $9+2$ array.
The central tubules are connected by a central sheath and are attached to one of the tubules of each peripheral doublet by a radial spoke. Thus,there are nine radial spokes.
The peripheral doublets are also interconnected by linkers.