What happens to a sarcomere when muscle length changes?

Answer 1

1. Arrangement of thick and thin filaments: In each sarcomere two sets of actin filaments extend partway toward the center. The myosin filaments are arranged such that they partially overlap the actin filaments. Myosin heads on each side point away from the center of the sarcomere.

2. During contraction, the interaction of myosin heads with the actin filaments pulls the thin filaments toward the center of the sarcomere. The actin and myosin filaments slide past each other.

3. Cross-bridges = attachement betwn myosin heads and binding sites on actin filaments.

4. When a muscle cell is stimulated, myosin heads are energized by ATP. They attach to adjacent actin filaments, and tilt in a short "power stroke" toward the center of the sarcomere. Each power sroke requires an ATP. With many power strokes in rapid succession, the actin filaments are made to slide past the myosin filaments.

Answer 2

1. Arrangement of thick and thin filaments: In each sarcomere two sets of actin filaments extend partway toward the center. The myosin filaments are arranged such that they partially overlap the actin filaments. Myosin heads on each side point away from the center of the sarcomere.

2. During contraction, the interaction of myosin heads with the actin filaments pulls the thin filaments toward the center of the sarcomere. The actin and myosin filaments slide past each other.

3. Cross-bridges = attachement betwn myosin heads and binding sites on actin filaments.

4. When a muscle cell is stimulated, myosin heads are energized by ATP. They attach to adjacent actin filaments, and tilt in a short "power stroke" toward the center of the sarcomere. Each power sroke requires an ATP. With many power strokes in rapid succession, the actin filaments are made to slide past the myosin filaments.

Answer 3

Yes the sarcomere length varies with the size of the muscle. This is because as the muscle contracts the thin filaments slide over the thick filaments making the sarcomere shrink in length.

Answer 4

A muscle at rest has bands that are lined up. When the sarcomere contract and lengthens, the bands distort to cause the muscle contraction. The A bands do not change their length.