During muscle contraction, the A band
A) stays the same width, and the I bands and H zone shorten.
B) and H zone stay the same width, and the I bands shorten.
C) shortens, and the I bands and H zone stay the same.
D) and H zone shorten, and the I bands stay the same.

Question

Quizplus · Accepted Answer

During muscle contraction, the A band (the dark band in the center of the sarcomere) stays the same width, while the I bands (lighter bands on either side of the A band) and H zone (the region in the center of the A band where there is no overlap between the thick and thin filaments) shorten. This is due to the sliding filament theory of muscle contraction, where the actin and myosin filaments slide past each other, causing the sarcomere to shorten.

During Muscle Contraction, the a Band