Sarcomeres are the basic building blocks of muscle. Arrangement of sarcomeres in series and parallel allow for the construction of muscles with a wide range of force-generating capacity. For each of the configurations of 10 sarcomeres in parts (a) - (d) below, plot the active force (T) generated by the structure against the configuration length (l), in μμm. Be sure to label key points, including the peak force generated by the structure, the length at which the structure generates peak force, and the minimum and maximum lengths at which the structure can generate active force. Assume that T = Torigin = Tinsertion, and that the maximum active force (T) generated by a single isolated sarcomere is 1 μμN.
a) 10 sarcomeres in parallel:
b) 10 sarcomeres in series:
c) 5 sarcomeres in parallel x 2 in series
d) 2 sarcomeres in parallel x 5 in series
e) Based on your results in parts (a) - (d), explain how the geometric arrangement of sarcomeres can generate muscles of different architectures (i.e., in peak force generation capacity of muscle, and in length operating range of muscle)
f) Optional: Under what conditions is the assumption that Torigin = Tinsertion true? Is this a reasonable assumption to make in the model of muscle? Why or why not?