The Z line is thin.
The Z line, also known as the Z disc, is a dark band found in the center of each sarcomere, the functional unit of a muscle fiber. It is a thin, dense structure that serves as an attachment point for the thin filaments of actin.
The Z line is essential for muscle contraction, as it helps to maintain the alignment of the sarcomere and allows for the sliding of the thick and thin filaments during muscle contraction.
The Z line is composed primarily of alpha-actinin, a protein that binds to actin and helps to anchor the thin filaments. It also contains other proteins, such as desmin and vinculin, which help to maintain the structural integrity of the Z line.
The Z line is visible under a light microscope and appears as a dark band due to the presence of the densely packed proteins.
