muscle bundle

A muscle bundle, also known as a fascicle, is a group of muscle fibers. These bundles are organized within skeletal muscles, which are responsible for movement and supporting the body's weight.1

Skeletal muscles are structured with connective tissue sheaths. The epimysium covers the entire muscle, while the perimysium divides the muscle into these bundles. Within each bundle are smaller cylindrical muscle fibers, or cells, each wrapped in a thin connective tissue sheath called the endomysium. These connective tissues, made of collagen, provide strength and support.1

Each muscle fiber contains myofibrils, which are the basic units of contraction. Myofibrils are composed of the proteins actin and myosin, and their interaction causes muscle contraction. The term "fascicle" originates from the Latin word for "bundle".123