Question

Knowing what you know about muscle function and excitation-contraction coupling, what are TWO factors that could allow a leg muscle in one animal to activate and relax more quickly than a leg muscle in another animal?

Answer 1

Two factors responsible for quick contraction and relaxation are-

a) motor unit recruitment

b)wave summation

Motor unit recruitment allows faster contractions as many notor units are activated and stimulated simultaneously, which produces rapid response.

Wave summation causes summation of two waves.

when second stimulus is applied before the completion of relaxation period of first stimulus,stronger contraction occurs.

This results into increased frequency of stimulation of muscle fibres

This occurs due to high calcium availability.