muscle spindle

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Related to Muscle spindles: Golgi tendon organs, joint receptors

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.
References in periodicals archive ?
Recent findings in humans demonstrate the importance of proprioceptive input from paraspinal muscle spindles for controlling spinal motion including regional repositioning of the lumbar spine and eliciting paraspinal muscle reflex activity.
Earlier studies by Burke and others (1976) have shown that the TVR is primarily attributable to muscle spindle Ia fibers, which are able to respond one-to-one to vibration frequencies of up to 200 Hz.
A-delta fibers which are small diameter-myelinated and pain-transmitting fiber demonstrate the greatest decrease in conduction velocity in response to the cooling (29), but afferent fibers that translate the proprioceptive information from muscle spindles to the CNS are type of I[alpha] and II meaning large myelinated fiber that have fast conduction (30).
The less we stimulate the muscle spindles by eliminating force, the more effectively the stretch reflex is inhibited.
(26) The purpose of this paper is to report the effects that single facet joint dysfunction have on the mean instantaneous frequency of muscle spindles located in trunk musculature during 1mm ramp and hold movements of the [L.sub.6] lumbar vertebra derived from secondary analyses of the previous study involving facet joint dysfunction and spinal manipulation.
The reason for choosing decreased peak hamstring torque as the measure of fatigue was based on the idea that fatigue of the hamstrings would lead to decreased sensory output of the muscle spindles associated with the hamstrings.
Their motor neurons are also being excited by the stretched hamstring muscle spindles, so there are two forces acting to oppose the intended hamstring relaxation.
Direct application of high frequency vibration on muscle and tendon activates Ia afferent of the muscle spindles and to a lesser extent, the secondary afferents and Ib afferents of the golgi tendon organ (Roll et al., 1989).
Few muscle spindles were identified in the muscle belly of the superficial bundle, one of them fused.
Assuming an effect of PNF a lower value was observed after stretching, which would indicate lower motor units recruited and/or their firing rate was inhibited by its own Golgi tendon organs and by the muscle spindles of its stretched antagonist (20).
One of these differences is that the discharge rate of Ia afferents from muscle spindles during eccentric contraction is higher than that during other types of muscle contraction, since an eccentric contraction involves the development of tension in the muscle spindle while the whole muscle is being lengthened (Burke, 1978; Ribot-Ciscar and Roll, 1998).
These mechanical stimuli are transmitted to the body where they stimulate muscle spindles. This leads to the activation of the alpha-motor neurons and initiates muscle contractions comparable to the tonic vibration reflex.