muscle spindle

(redirected from Muscle spindle organ)
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spindle

 [spin´d'l]
1. a pin tapered at one end or both ends, or something with this shape.
2. the thin, tapering figure occurring during metaphase of cell division, composed of microtubules radiating from the centrioles and connecting to the chromosomes at their centromeres. Called also mitotic spindle.
mitotic spindle spindle (def. 2).
muscle spindle a mechanoreceptor found between the skeletal muscle fibers; the muscle spindles are arranged in parallel with muscle fibers, and respond to passive stretch of the muscle but cease to discharge if the muscle contracts isotonically, thus signaling muscle length. The muscle spindle is the receptor responsible for the stretch or myotatic reflex.
sleep s's bursts of activity of a particular waveform in the electroencephalogram in light or early sleep.

neu·ro·mus·cu·lar spin·dle

a fusiform end organ in skeletal muscle in which afferent and a few efferent nerve fibers terminate; it contains from 3 to 10 modified striated muscle fibers (intrafusal fibers) that are much smaller than the ordinary muscle fibers, are separated from them by a capsule that encloses the organ, and are innervated by the thin axon of a gamma motoneuron (gamma motor fiber); the sensory endings that occur on the intrafusal fibers are either annulospiral or flower-spray endings; this sensory end organ is particularly sensitive to passive stretching of the muscle in which it is enclosed.

muscle spindle

n.
A sensory receptor in a muscle that responds to the stretching of tissue. Also called stretch receptor.

neu·ro·mus·cu·lar spin·dle

(nūr'ō-mŭs'kyū-lăr spin'dĕl)
A fusiform end organ in skeletal muscle in which afferent and a few efferent nerve fibers terminate; this sensory end organ is particularly sensitive to passive stretch of the muscle in which it is enclosed.
Synonym(s): muscle spindle.

muscle spindle

a PROPRIOCEPTOR found in skeletal muscle in the form of a capsule containing specialized muscle cells and nerve endings. Change in length or tension of muscle cells stimulates the spindle.