What are the parallelly arranged filaments in the sarcoplasm called?

.Skeletal muscles are known as voluntary muscles because their activities are under the voluntary control of the nervous system. Each organised skeletal muscle in the body is made of a number of muscle bundles or fascicles held together by a common collagenous connective tissue layer called fasciA.Each muscle fiber is lined by the plasma membrane called sarcolemma enclosing the sarcoplasm.A characteristic feature of the muscle fiber is the presence of a large number of parallelly arranged filaments in the sarcoplasm called myofilaments or myofibrils.