The contractile, or functional, unit of a muscle fiber is __________.
Biology · High School · Sun Jan 24 2021
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The contractile, or functional, unit of a muscle fiber is sarcomere.
Explanation: The plasma membrane of a muscle fibre i.e sarcolemma, has parallelly arranged filaments called myofibrils. Myofibrils contain alternate light and dark bands. The light bands contain actin and is called I-band or isotropic band whereas the dark bands contain myosin and is called A-band or anisotropic band. Each I band has an elastic fibre called Z line which bisects it and the filaments are attached to this Z line. The region between two successive Z lines is the functional unit of contraction and is called sarcomere.