Supercontracting muscle: producing tension over extreme muscle lengths

摘要: Muscle mechanics dictates a trade-off between the ability of muscle to generate isometric force and its length. This intrinsic is result need for overlap thick thin filaments upon extension sarcomere limitations imposed by physical interference with Z-disk contraction. However, previously published data indicate that chameleons are able produce nearly constant tongue retraction over wide range lengths, made possible presence supercontracting in retractors. Investigation length/tension properties ultrastructure retractor closely related agamid lizard (Pogona vitticeps) indicates tension at extreme elongation probably derived feature chameleons. Whereas unique among vertebrates possessing muscle, this seems be common phenomenon invertebrates. several invertebrate groups coupled large changes length might more general solution problem.