CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
Question

Which of the following regions decreases in length during muscle contraction?

A
2 and 3
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
3 and 4
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
1, 2, and 4
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
2, 3, and 4
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct option is D 2, 3, and 4
Region 1 is the A band that contains thick and thin filaments overlapping each other. Region 2 here is the I band which is formed only of thin actin filaments. Region 3 is the H zone, formed only of thick myosin filaments. Finally, region 4 on the diagram is the area between the Z lines, and is called a sarcomere.
During muscle contraction, the I band reduces in size as the overlap between the thick filaments and the thin filaments increases. The H zone also decreases in length because of the same reason. As the actin filaments come closer to the M-line, the Z lines come closer together, so the sarcomere also decreases in length. The A band is the only part of the sarcomere that does not change length during muscle contraction.

flag
Suggest Corrections
thumbs-up
1
BNAT
mid-banner-image