FIGURE 10.
Meridional spectra of (a) a relaxed bundle at 2.2 μm sarcomere length; (b) the same relaxed bundle after stretch to 3.4 μm, bearing 0.22 Po passive tension; (c) relaxed bundle at sarcomere length 2.2 μm; and (d) the same bundle at the plateau of an isometric tetanus. Exposure duration 10 s. The marked reduction of M3 in b, relative to the unstretched state in a, is due to the large degree of reflection broadening observed at long sarcomere lengths (2.8-fold) compared to that in activation at full overlap (1.7-fold), the absence of the increase in IM3 of ∼1.7-fold upon activation that strengthens the reflection in d, and the reduction of scattering mass in the beam due to the stretch.