Above- a sand dollar stripped of soft tissues, revealing the porous endoskeleton or stereom. SEM image by Wolf Fahrenbach.
The distance between each tick mark is 400nm (= 0.0004mm, or 1/2500th of a millimeter).
A veil comprised of bundles of cytoskeletal filaments lies atop the nucleus of a detergent-extracted CHO cell. While these fibers have a structural purpose, they are also vital to numerous reactions and cellular events- they continually form, dissolve, then reemerge- they are anything but static.