PHYSIOLOGY
SARCOMERE
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
It grows larger
|
|
|
It disappears
|
|
|
It stays the same length
|
|
|
None of the above
|
Detailed explanation-1: -Muscle contraction is brought about by sliding movement of actin filaments over myosin filaments. When a muscle fibril contracts, it’s A band remains constant and I band shortens. H – Zone disappears. M – line and Z – line also come closer.
Detailed explanation-2: -As a sarcomere is shortened, the zone of overlap is reduced as the thin filaments reach the H zone, which is composed of myosin tails. Because it is myosin heads that form cross-bridges, actin will not bind to myosin in this zone, reducing the tension produced by this myofiber.
Detailed explanation-3: -During muscle contraction, the thin filaments slide past the thick filaments or M-line. This shortens the sarcomere. During this, the A band which is composed of myosin remains the same. The M line remains in the center of the sarcomere.