Q-disk

Q-disk [discus anisotropus – LNH (The Leningrad histologic nomenclature); synonyms: a disk Q, a disk A] – a myofibrillar disk with double refraction within which thick myofilaments are located.

 
Whether you know that:

Most of women is capable to derive more pleasure from contemplation of the beautiful body in a mirror, than from sex. So, women, you aim at symmetry.