Human musculature. Computer artwork showing the superficial muscles of a human male body and the structure of skeletal muscle (bottom). Single muscle fibres (large red cylinder at right) are made up of myofibrils, which consist of myosin (red, far right) and actin (blue) filaments. Muscle fibres are covered with endomysium connective tissue. They are grouped into bundles called fascicles, which are wrapped in perimysium connective tissue. Groups of fascicles form the muscle, which is covered by epimysium connective tissue.