Sarcomere

Myosin

A motor protein that interacts with actin filaments to facilitate muscle contraction uses ATP to generate force and movement within muscle fibers.

Actin

A globular protein that forms thin filaments in muscle fibers. plays a crucial role in muscle contraction by interacting with myosin.

z-line

The dense protein structure that anchors the thin actin filaments in a sarcomere, marking the boundary between adjacent sarcomeres.

m line

The middle line of a sarcomere that anchors the thick myosin filaments and serves as a structural support, helping to maintain the alignment of the filaments during muscle contraction.

H zone

The region of a sarcomere that contains only thick myosin filaments, appearing lighter under a microscope and located between the A bands of adjacent sarcomeres.

A band

The dark band in a sarcomere that contains both thick myosin filaments and overlapping thin actin filaments, contributing to the striated appearance of skeletal muscle.

I band

The light band in a sarcomere that contains only thin actin filaments and is found on either side of the A band, contributing to the striated appearance of skeletal muscle.