Figure 7

Feedback length effects. Feedback of internal shortening on myoplasmic [C a^{2 +} ] _myo transient. The protocol used comprises of 9 beats of isometric contraction followed by a 0.8 s rest interval and beat 10 (shown above) when the cell is allowed to internally shorten (∙) or held at a fixed sarcomere length of 2.2 μ m (∗). (A) The sarcomere length in both the cases shows the degree of contraction when the cell is allowed to internally shorten via a series elastic element (KSE = 2). (B) Isosarcometric case shows enhanced force when compared to the isometric case. The inset shows corresponding steady state F-Ca relationships (C) As seen in experimental studies, the isosarcometric case shows a modest decrease in [C a^{2 +} ] _myo transient. Model generated data corresponds to an idealized rat ventricular myocyte at 22.5°C.