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How do the epimysium, perimysium, and endomysium support skeletal muscle?
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muscle
The structure of striated, or skeletal, muscle. Striated muscle tissue, such as the tissue of the human biceps muscle, consists of long fine fibers, each of which is in effect a bundle of finer myofibrils. Within each myofibril are filaments of the proteins myosin and actin; these filaments slide past one another as the muscle contracts and expands. On each myofibril, regularly occurring dark bands, called Z lines, can be seen where actin and myosin filaments overlap. The region between two Z lines is called a sarcomere; sarcomeres can be considered the primary structural and functional unit of muscle tissue.
Skeletal muscle is organized by layers of connective tissue that provide structural support and facilitate the transmission of force generated by muscle fibers to tendons and bones. These layers are organized as follows:1
- Endomysium: This is the connective tissue layer that surrounds individual muscle fibers.
- Perimysium: This layer surrounds bundles of muscle fibers, which are known as fascicles.1
- Epimysium: This is the external connective-tissue sheath that surrounds the entire muscle.2
Together, these connective tissues serve a critical mechanical role by helping to transmit the force produced by the contraction of myofibrils within the muscle fibers to the tendons, ultimately enabling body movement.1