Otolith


Also found in: Dictionary, Medical, Wikipedia.

otolith

[′ōd·ə‚lith]
(anatomy)
A calcareous concretion on the end of a sensory hair cell in the vertebrate ear and in some invertebrates.

Otolith

 

a solid formation on the surface of the mechanoreceptor cells in the organs of equilibrium of some invertebrates and all vertebrates. Otoliths of different animals vary in origin, size, and structure: they can be secreted by cells or introduced from outside, for example, grains of sand serve as otoliths in crayfish. Mammalian otoliths are usually crystals of calcite (CaCO3) up to 10 microns (μ.) long and 1–3 μ wide.

As otoliths shift in response to acceleration and changes in body position, they mechanically irritate the underlying ciliated receptor cells, which then send appropriate signals to the brain.

The action of otoliths has been demonstrated in experiments with crayfish. The grains of sand that serve as the crayfish’s otoliths were replaced during molting by iron filings, and a magnet was placed above the animal to attract the filings. The crayfish reversed its sense of orientation, turned over, and swam with its abdomen up.

O. B. IL’INSKII

References in periodicals archive ?
Otoliths were measured (otolith length - OL) and photographed in pairs in a way that both sides were visible.
5 megapixels of each otolith section were obtained under transmitted light using a stereoscopic microscope Stemi DV4 (Carl-Zeiss) fitted with a Cannon[TM] Power Shot G6 digital camera.
Data on length and width were registered for each otolith through their observation in a stereoscopic microscope with a graduated ocular lens.
Morphological indices and otolith microstructure of Atlantic croaker, Micropogonias undulatus, as indicators of habitat quality along an estuarine pollution gradient.
Their chemical composition affords the possibility of environmental reconstruction that, when matched with otolith biochronologies, can allow an individual fish to be placed retrospectively within time and space throughout its life (Campana and Thorrold 2001:37).
For salmon migration, theres still a way to go: now that they have shown the approach has potential, in order to apply the approach, the team will need to create tools to explore the detailed data from otoliths using sound.
Otolith microchemistry has been successfully applied to the study of small coastal pelagic fish using transitional environments (Kimura et al.
The theoretical basis behind stock identification that is based on otolith chemistry is that otoliths are deposited at, or very close to, oxygen isotopic equilibrium with ambient seawater and thus scientists can create a record of the environmental changes that an individual fish experiences through time (Gao et al.
The keys to Llopiz's research are tiny calcium carbonate stones, called otoliths, that grow from birth in fishes' heads.
The objective of this study was to compare the feasibilities and precisions of age estimations of these two loaches using five different structures which were scale, otolith, vertebra, opercular bone and cleithrum.
We recorded the presence of fish by identifying scales, otoliths, and pharyngeal teeth in the sample.
3B) is as follows: Roughly triangular, the edge of dorsal is smooth, with one slight gap at the posterior end; the ventral edge is irregularity with two distinct protuberances on the ventral edge, the anterior of otolith incline to the ventral slightly.