I-Band
Interactions between actin and myosin filaments of the sarcomere are responsible for muscle contractions. The I bands contain only thin (actin) filaments, whereas the A bands contain thick (myosin) filaments.
Myosin. The A band has thick (myosin) and thin (actin) filaments.
It's the I Band.
H-Zone
The thin filaments are actin, and the thick filaments are myosin. The filaments run parrel to one another along the length of the sarcomere.The dark bands that occur in the middle of the sarcomere are regions where the thick filaments and thin filaments overlap.
It is a lighter region that contains thick filaments, but no thin filaments.
FALSE
A sarcomere consists of thin and thick filaments arranged so they can slide over each other. The boundary of the sarcomere are the Z lines. Thin filaments extend from the Z lines and overlap with thick filaments in the middle of the sarcomere. The I band is on each side of the Z line where only thin filaments occur. The A band is the length of the thick filaments and is divided into three parts; the zone of overlap is on each end where thin and thick filaments occur, the H band is in the middle and has only thick filaments, and the M line is the center of the A band.
A-band. It has actin (thin protein) and myosin (thick protein) overlapping within it
There more thin filaments than thick filaments in smooth muscle. The ratio is of the thin to thick filaments in the smooth muscle is approximately 15:1.
Histological PerspectiveBoth ends of the muscle are pulled together. This is because each muscle fiber is divided into contractile units called sarcomeres. Each sarcomere is composed of layers of thin and thick filaments, Actin and Myosinrespectively. The thick filaments, myosin, are located in the center of the sarcomere, a region called the A-Band. On either side of each A-Band, is a region called the I-Band. The I-Band is primarily composed of the thin filaments (Actin), although the thin filaments do overlap with the thick filaments within a sub region of the A-band called the zone of overlap.As the muscle contracts the thick filaments pull the thin filaments together on either side, resulting in the apparent contraction of the muscle on both sides.Gross Anatomical Perspective.However, because a muscle is anchored at the origin of the stationary bone while its other end attaches at the insertion of the articulating bone and the net force of the contracting muscle pulls the insertion of the muscle to its origin.It follows that: The correct answer is toward the origin.