Muscle Fiber
Normal Muscle Fiber Histology
From outside to inside lies the skin and then superficial fascia.
Epimysium envelopes the muscle.
Perimysium divides the muscle into fascicles (a bundle of skeletal muscle fibers).
Endomysium lies within the muscle fascicle: it comprises a loose areolar connective tissue that maintains the extracellular environment for proper muscle cell functioning.
Muscle cells (aka myocytes or muscle fibers).
- Skeletal muscle fibers are multinucleated, which reflects the process of muscle cell formation: mature muscle cells form from fused myoblast cells (embryonic cells); each myoblast cell contributes its nucleus to the adult cell.
- Myocytes comprise numerous myofibrils, which each comprise numerous myofilaments: fewer thick, myosin filaments and more numerous thin, actin filaments.