FIGURE 11.
The isotonic transient response of a sarcomeric structure to: (A) a small drop, (B) a large drop, and (C) a rise in the load, when the initial value of the load is chosen precisely to stall the contraction. The upper graph shows the force per myosin filament as a function of time. The lower graph displays the length change per half sarcomere and the number of attached myosin heads per myosin filament, which is a measure of the fiber stiffness. The data were computed with N = 300, ɛ1 = 0.8 and with 50 myosin filaments acting in parallel. The results were averaged over 125 events (which has the same effect as simulating that number of sarcomeres in series). A small drop in the load synchronizes the cross-bridges and therefore causes observable macroscopic oscillations (A). The oscillations are less pronounced, but still visible after a small increase in the load (C).