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PSY 212
Control of Movement
| Term | Definition |
|---|---|
| flexion | contraction of a flexor muscle |
| extension | contraction of an extensor muscles (anti-gravity) |
| extrafusal muscle fibers | ultimately result in muscle movement via innervation by alpha motor neurons |
| intrafusal muscle fibers | also known as muscle spindles; sensory fibers that relay information about muscle tension back to the CNS via gamma motor neurons |
| actin | thin, filamentous protein that forms the structural framework of the muscle fibers |
| myosin | thick, motor protein that interacts with actin to create the contractile force necessary for muscle contraction |
| myofibrils | contains actin and myosin |
| monosynaptic stretch reflex | when muscles are rapidly lengthened, afferent neurons from intrafusal fibers synapse in the spinal cord with efferent neurons (alpha motor neurons) |
| motor unit | collectively refers to the muscle fibers served by a single axon |