muscle spindle


Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.
Related to muscle spindle: Golgi tendon organ, Intrafusal muscle fibers

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 ?
C and D: Note the peripheral nuclei (white arrows), muscle spindle capsule (thick arrows), intrafusal fibers (arrow heads) and capillaries (thin arrows).
(2,4) The facet joint capsule and surrounding musculature have numerous proprioceptors in the form of muscle spindles and type I and type II afferents.
Most of the sensory fibrils entering each segment of the spinal cord terminate on interneurons, but a small number of large sensory fibres from the muscle spindles terminate directly on the anterior motorneurons.
(1976b) The responses of human muscle spindle endings to vibration during isometric contraction.
Liu JX, Thornell LE and Pedrosa-Domell F (2003): Muscle spindles in the deep muscles of the human neck: A morphological and immunocytochemical study.
The responses of human muscle spindle endings to vibration of non contracting muscles, J Physiol 1976; 261: 673-693.
Gamma activation exerts a stretch on the muscle spindle. Sensory neurons from the muscle spindle synapse on alpha motor neurons in the spinal cord and activate them.
Primary sensory receptors that are employed in movement are muscle spindles and Golgi tendon organs (Gardner, 1968; Liss, 1990).
It requires the integration of sensory information from peripheral proprioceptors (muscle spindles, Golgi tendon organs, articular and cutaneous mechanoreceptors), vision and the vestibular apparatus.
The EMG activity is elicited during a muscle stretch by the muscle spindles that represent a portion of the neuromuscular system.
Thus, WBV exercise acutely enhances the pattern of the neuromuscular system due to the physiological mechanism called "tonic vibration reflex" (TVR), where muscle spindle reflexes facilitate the activation of Iamotoneurons, leading to muscle contractions (Hagbarth and Eklund, 1966; Lance et al., 1973).