Assertion: muscle fiber | /r/MadeOf | many myofibrils
Facets:
Source sentences:
text: Just as each muscle fiber contains many myofibrils, each myofibril is in turn composed of many filaments.
text: Each muscle fiber contains many myofibrils, which are bundles of actin and myosin filaments organized into a chain of repeating units called sarcomeres.
text: Muscle fibers contain many myofibrils, the contractile unit of muscles.