When a muscle contracts, the actin and myosin myofilaments come together, the H zones and I zones shrink and become very narrow. The A band does not changing during contraction.
Prosomes form sarcomere-like banding patterns in skeletal, cardiac, and smooth muscle cells.Actin and Myosin proteins
A muscle that contracts shortens whereas a muscle that relaxes lengthens.
The Diaphragm.
The banding pattern visible in striated muscle is due to the arrangement of thick and thin filaments within muscle fibers. The alternating dark A bands (containing thick filaments) and light I bands (containing thin filaments) create the striated appearance. This banding pattern is essential for the function of muscle contraction.
A muscle becomes shorter when it contracts.
When a muscle contracts, it shortens in length.
When a muscle contracts, it pulls with a force generated by the muscle fibers contracting and shortening.
When a muscle contracts but does not change length, it is undergoing isometric contraction. During this type of contraction, the muscle generates tension without any visible movement or change in the muscle's length. This is commonly observed when holding a weight in a fixed position or pushing against an immovable object. Isometric contractions are important for stabilizing joints and maintaining posture.
When one muscle in a pair contracts the other expands.
shortens
Flexion
Flexion