Assertion: muscle fiber's filament | /r/HasProperty | within each myofibril
Facets:
Source sentences:
text: Within each myofibril are filaments of the proteins myosin and actin; these filaments slide past one another as the muscle contracts and expands.
text: Within each myofibril are filaments of the proteins myosin and actin; these filaments slide past one another as the muscle contracts and expands.