A contractile unit in a striated muscle fiber (cell) extending from one Z disc to the next Z disc; functional contractile unit within muscle fiber
A synapse between the axon terminals of a motor neuron and the sarcolemma of a muscle fiber (cell); an area where the axon of a motor neuron terminates and synapses with a skeletal muscle fiber.
alternating light and dark
An irregular transverse thickening of sarcolemma that contains desmosomes, which hold cardiac muscle fibers (cells) together, and gap junctions, which aid in conduction of muscle action potentials from now fiber to the next
The attachment of a muscle tendon to a stationary bone or the end opposite the insertion
The attachment of a muscle tendon to a moveable bone or the end opposite the origin
the muscle directly responsible for producing a desired motion. Also called an agonist
Muscle responsible for action in the opposite direction of an agonist or the resistance to an agonist. (relaxes: lengthens)
Muscle primary responsible for the action (movement); (contracts: shortens)
agonist (prime mover)
Muscle that assist an agonist, often by supplementing the contraction force.