• Source: Nuclear bag fiber

A nuclear bag fiber is a type of intrafusal muscle fiber that lies in the center of a muscle spindle. Each has many nuclei concentrated in bags and they cause excitation of the primary sensory fibers.
There are two kinds of bag fibers based upon contraction speed and motor innervation.

BAG2 fibers are the largest. They have no striations in middle region and swell to enclose nuclei, hence their name.
BAG1 fibers, smaller than BAG2.
Both bag types extend beyond the spindle capsule.
These sense dynamic length of the muscle. They are sensitive to length and velocity.




See also


Nuclear chain fiber
List of distinct cell types in the adult human body




References






External links


http://www.unmc.edu/Physiology/Mann/mann11.html Archived 2007-07-03 at the Wayback Machine

Kata Kunci Pencarian:

• Nuclear bag fiber
• Nuclear chain fiber
• Gamma motor neuron
• Type II sensory fiber
• Intrafusal muscle fiber
• Spinocerebellar tracts
• Type Ia sensory fiber
• Muscle spindle
• Beta motor neuron
• Secondary sensory endings