of the actin that will bind to the myosin during muscle contraction. The I band is the part of the actin that is not bound to the myosin, but it will still move during muscle contraction. The H zone is the space in between two adjacent actin that will shrink when the muscle begins to contract. The Z disk is the part of the microfilament that characterizes the overall end of each side of the sarcomere, a structural unit of a myofibril.

; Proteins Limiting MicrofilamentsThese