- Extrafusal muscle fiber
Extrafusal muscle fibers are a class of
muscle fiber innervated byalpha motor neuron s.They generate tension, do mechanical work and allow for movement by contracting.
Compare with
intrafusal muscle fiber - is of sensory type and innervated by gammamotor neurons .Extrafusal muscle fibers and associated alpha motor neurons are called a
motor unit . The connection between alpha motor neuron and extrafusal muscle fiber is aneuromuscular junction , and the neurotransmitter responsible for contraction isacetylcholine .External links
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* [http://www.blackwellpublishing.com/11thhour/matt/about/u4c12a.html Cartoon of intrafusal vs. extrafusal fibers]
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