Nuclear bag fiber

Nuclear bag fiber
Nuclear bag fiber
Latin myofibra sacculiformis
Code TH H3.03.00.0.00013

A nuclear bag fiber is a type of intrafusal muscle fiber that lies in the center of a muscle spindle. Each has a large number of nuclei concentrated in bags and they cause excitation of both the primary and secondary nerve fibers.

There are 2 kinds of bag fibers based upon contraction speed and motor innervation.

1) Bag2 fibers - are the largest. They have no striations in middle region and swell to enclose nuclei (hence their name)

2) Bag1 fibers - are smaller than bag2.

Both bag types extend beyond the spindle capsule.


See also

External links

v · d · eNervous system, receptors: somatosensory system (GA 10.1059)
Medial lemniscus
Spinothalamic tract

M: PNS

anat(h/r/t/c/b/l/s/a)/phys(r)/devp/prot/nttr/nttm/ntrp

noco/auto/cong/tumr, sysi/epon, injr

proc, drug(N1B)

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