Muscle fibers contract when Z lines move _________ and the sarcomeres _________.
A) farther apart; stretch
B) farther apart; shorten
C) closer together; stretch
D) closer together; shorten

Question

Quizplus · Accepted Answer

Muscle fibers contract when the Z lines move closer together and the sarcomeres shorten. This is due to the sliding filament theory of muscle contraction, in which the actin filaments slide past the myosin filaments, pulling the Z lines closer together and causing the muscle to contract.

Muscle Fibers Contract When Z Lines Move _________ and the Sarcomeres