MUSCLE PHYSIOLOGY

Detailed explanation-1: -The tail of a myosin molecule connects with other myosin molecules to form the central region of a thick filament near the M line, whereas the heads align on either side of the thick filament where the thin filaments overlap. The primary component of thin filaments is the actin protein.

Detailed explanation-2: -M-line is the attachment site for the thick filaments. It is in the center of the A band. It is present in the center of the sarcomere. During muscle contraction, the thin filaments slide past the thick filaments or M-line.

Detailed explanation-3: -The myosin head moves toward the M line, pulling the actin along with it. As the actin is pulled, the filaments move approximately 10 nm toward the M line. This movement is called the power stroke, as it is the step at which force is produced.

Detailed explanation-4: -Thin filaments (or actin filament) are anchored at one end at the Z-band. Titin is anchored to both the Z-band and the M-line. Thick filaments are anchored in the middle of the sarcomere at the M-line.