intrafusal fiber


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intrafusal fiber

[¦in·trə′fyüz·əl ′fī·bər]
(histology)
Any of the striated muscle fibers contained in a muscle spindle.
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References in periodicals archive ?
The muscle spindles in the EDL muscle were observed in the two studied groups and were found to have a normal organizational pattern, that is, smaller and thinner intrafusal fibers, surrounded by a connective tissue capsule (Figs.
In the CP group, the muscle spindle area and the mean cross-sectional area of the intrafusal fibers were 26 % smaller when compared to the CTL group (Figs.
Regarding the muscle spindles, the absence of weight discharge is known to be able to reduce the cross-section area of the intrafusal fibers, decrease the diameter of the equatorial region and fragment the nerve endings (Zhu et al., 2008).
Thus, gamma activation and contraction of intrafusal fibers can drive alpha activation and the contraction of entire muscle (Nielsen et al., 2007).
(2) This is due to the presence of cholinergic neuromuscular junctions between the a-motor neurons and the extrafusal fibers, and the 7-motor neurons and the intrafusal fibers which form the muscle spindle organ.