- - central s. a central group of microtubules (continuous fibers) that course uninterrupted, between the asters, in contrast to the microtubules attached to the individual chromosomes (s. fibers).- His s. SYN: aortic s..- Krukenberg s. a vertical fusiform area of melanin pigmentation on the posterior surface of the central cornea.- Kühne s. SYN: neuromuscular s..- mitotic s. the fusiform figure characteristic of a dividing cell; it consists of microtubules (s. fibers), some of which become attached to each chromosome at its centromere and are involved in chromosomal movement; other microtubules (continuous fibers) pass from pole to pole. SYN: nuclear s..- neuromuscular s. a fusiform end organ in skeletal muscle in which afferent and a few efferent nerve fibers terminate; it contains from 3–10 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 stretch of the muscle in which it is enclosed. SYN: Kühne s., muscle s..- sleep s. the electroencephalographic record of 14-per-second bursts of wave frequency seen on EEG examination.
* * *spin·dle 'spin-dəl n1) something shaped like a round stick or pin with tapered ends: asa) a network of chiefly microtubular fibers along which the chromosomes are distributed during mitosis and meiosisb) MUSCLE SPINDLE2) SLEEP SPINDLE
* * *n.a collection of fibres seen in a cell when it is dividing. The fibres radiate from the two ends (poles) and meet at the centre (the equator) giving a structure shaped like two cones placed base to base. It plays an important part in chromosome movement in mitosis and meiosis and is also involved in division of the cytoplasm.
* * *spin·dle (spinґdəl) 1. a rod or pin that tapers at one end or both ends, or something having this shape. 2. the fusiform figure occurring in the cell nucleus during the metaphase of mitosis, composed of microtubules radiating from the centrioles and connecting the centrally located chromosomes at their centromeres. Called also mitotic s. and nuclear s. 3. a type of fusiform brain wave occurring on the electroencephalogram in groups at a frequency of about 14 per second, usually while the patient is falling asleep. 4. muscle s.
Medical dictionary. 2011.