Cross-cuts of cilia showing the typical 9X2 +2 arrangement of microtubules within the cytoplasm ( ring of 9 doublets plus 2 single microtubules in the center). The cell membrane envelopes each cilium.

• 纤毛横切面显示了典型的9X2+2微管排列结构（环绕周边的9组二联微管加中间两条单独的微管。胞膜覆盖在纤毛表面。