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A&P CH8 Key terms
A&P CH8 Muscular System
| Term | Definition |
|---|---|
| actin | a protein that, with myosin, contracts muscle fibers |
| antagonist | a muscle that acts in opposition to a prime mover |
| aponeurosis | a sheet of connective tissue by which certain muscles are attached to adjacent muscles |
| fascia | a sheet of fibrous connective tissue that encloses a muscle |
| insertion | the end of a muscle attached to a movable part |
| motor neuron | a neuron that transmits impulses from the central nervous system to an effector |
| motor unit | a motor neuron and its associated muscle fibers |
| muscle impulse | impulse that travels along the sarcolemma to the transverse tubules |
| myofibril | contractile fibers within muscle cells |
| myosin | a protein that, with actin, contracts and relaxes muscle fibers |
| neurotransmitter | chemical that an axon end secretes to stimulate a muscle fiber to contract or a neuron to fire an impulse |
| origin | end of a muscle that attaches to a relatively immovable part |
| oxygen debt | the amount of oxygen required after physical exercise to convert accumulated lactic acid to glucose |
| prime mover | muscle responsible for a particular body movement |
| recruitment | increase in number of motor units activated as stimulation intensity increases |
| sarcomere | the structural and functional unit of a myofibril |
| synergist | a muscle that assists the action of a prime mover |
| threshold stimulus | stimulation level that must be exceeded to elicit a nerve impulse or a muscle contraction |