noun, plural: statoliths
(zoology) An otolith, i.e. a crystalline particle of calcium carbonate and a protein adhering to the gelatinous membrane of the maculae of the utricle and the saccule
(botany) An inclusion, e.g. starch grains, in plant cells and is involved in geotropic responses
Statolith has two major meanings in biology. In zoology, it pertains to otolith. It is a particle that is crystalline in structure due to its calcium carbonate composition. It is found in the inner ear of vertebrates. In particular, it adheres to the gelatinous membrane of the maculae of the utricle and the saccule. Saccule and utricle of the inner ear make the otolith organs in vertebrates. Thus, otoliths are associated with the sense of balance. Movement of otoliths (for instance, due to a change in the position), stimulates the sensory hair cells to send impulses to the brain. The otoliths are also a directional indicator. In higher aquatic and terrestrial vertebrates, the otoliths are involved in sound detection. The otoliths are also sensitive to gravity and linear acceleration.
In botany, the statolith may pertain to any of the inclusions in plant cells involved in geotropic responses. The statoliths, e.g. starch grains, are involved in sensing gravity. They are found in statocytes, specialized amyloplasts in the root cap.
Word origin: Ancient Greek stásis (“standing”) + líthos (“stone”)