Refer to the figure showing a sarcomere when it is relaxed. When the muscle contracts, _______ will become more narrow in the sarcomere.

Question

Refer to the figure showing a sarcomere when it is relaxed.  When the muscle contracts, _______ will become more narrow in the sarcomere.

Quizplus · Accepted Answer

During muscle contraction, the sarcomere shortens as the thin filaments (actin) slide over the thick filaments (myosin). This results in a reduction in the width of both the I band (the region containing only actin filaments) and the H zone (the region containing only myosin filaments). Therefore, both the I band and the H zone become more narrow in the sarcomere during muscle contraction.

Refer to the Figure Showing a Sarcomere When It Is