cochlea


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cochlea

 [kok´le-ah]
a spiral tube shaped like a snail shell, forming part of the inner ear; it is the essential organ of hearing. adj., adj coch´lear.

The cochlea is filled with fluid and is connected with the middle ear by two membrane-covered openings, the oval window (fenestra vestibuli) and the round window (fenestra cochleae). Inside it is the organ of corti, a structure of highly specialized cells that translate sound vibrations into nerve impulses. The cells of this organ have tiny hairlike strands (cilia) that protrude into the fluid of the cochlea.

Sound vibrations are relayed from the tympanic membrane (eardrum) by the bones of hearing in the middle ear to the oval window, where they set up corresponding vibrations in the fluid of the cochlea. These vibrations move the cilia of the organ of Corti, which then sends nerve impulses to the brain.

coch·le·a

, pl.

co·chle·ae

(kok'lē-ă, lē-ē), [TA]
The snail shell-shaped dense bone in the petrous portion of the temporal bone, forming the anterior division of the labyrinth or internal ear (bony cochlea). It surrounds a spiral canal of two-and-one-half turns around a central core, the modiolus; this spiral canal contains the scala vestibuli, scala media consisting of the membranous cochlea or cochlear duct in which is located the spiral organ (Corti), and scala tympani. The scala vestibuli is separated from the scala media by the Reissner membrane, and the basilar membrane separates the scala media from the scala tympani.
[L. snail shell]

cochlea

(kŏk′lē-ə, kō′klē-ə)
n. pl. coch·leae (-lē-ē′, -lē-ī′) also coch·leas
A spiral-shaped cavity of the inner ear that resembles a snail shell and contains nerve endings essential for hearing.

coch′le·ar adj.

bony labyrinth

The bone encasement of the inner ear which is filled with perilymph and contains 3 cavities:
(1) The cochlea, which houses the sensory part of the auditory system;
(2) The semicircular canals, which are sensitive to rotational movement;
(3) The vestibule, which contains the sacculus and utriculus, which are sensitive to linear movement.

coch·lea

, pl. cochleae (koklē-ă, -ē) [TA]
A conic cavity in the petrous portion of the temporal bone, forming one of the divisions of the labyrinth or internal ear. It consists of a spiral canal making two-and-a-half turns around a central core of spongy bone, the modiolus; this spiral canal of the cochlea contains the membranous cochlea, or cochlear duct, in which is the spiral organ (Corti organ).
[L. snail shell]
Enlarge picture
STRUCTURES OF THE COCHLEA

cochlea

(kŏk′lē-ă) [Gr. kokhlos, land snail]
A winding cone-shaped tube forming a portion of the bony labyrinth of the inner ear. It contains the organ of Corti, the receptor for hearing.

The cochlea is coiled, resembling a snail shell, winding two and three quarters turns about a central bony axis, the modiolus. Projecting outward from the modiolus, a thin bony plate, the spiral lamina, partially divides the cochlear canal into an upper passageway, the scala vestibuli, and a lower one, the scala tympani. Between the two scalae is the cochlear duct, the auditory portion of the membranous labyrinth. The spiral organ (of Corti) lies on its floor. The base of the cochlea adjoins the vestibule. At the cupola or tip, the two scalae are joined at the helicotrema.

See: illustrationcochlear (-ăr), adjective

cochlea

The structure in the inner ear containing the coiled transducer, the organ of Corti, that converts sound energy into nerve impulse information. The cochlea resembles a snail shell.
Cochleaclick for a larger image
Fig. 110 Cochlea . Cross section.

cochlea

a part of the inner ear which is concerned with the detection of the pitch and volume of sound received by the ear. A projection of the SACCULE (2), it occurs in some reptiles, birds and mammals. In the mammal it is a coiled tube consisting of three parallel canals and contains the organ of Corti, the part which actually responds to sound.

Cochlea

The hearing part of the inner ear. This snail-shaped structure contains fluid and thousands of microscopic hair cells tuned to various frequencies, in addition to the organ of Corti (the receptor for hearing).

coch·lea

, pl. cochleae (koklē-ă, -ē) [TA]
Snail shell-shaped dense bone in the petrous portion of the temporal bone, forming the anterior division of the labyrinth or internal ear.
[L. snail shell]
References in periodicals archive ?
"The action of Activin A and follistatin is so precisely timed during development that any disturbance can negatively affect the organization of the cochlea," says Doetzlhofer.
Diluted in blocking solution, the primary antibody against LaminB1 (1:400; Abcam, Cambridge, UK) was applied to the cochlea sections overnight at 4 [degrees]C.
A higher radiation dose to the cochlea has been consistently associated with greater hearing loss.[5],[8],[16],[19],[28],[29].[30] We found that among the radiation-injured patients, we studied, the average tumor size (7.1 [+ or -] 6 cm[3]) was bigger than that in both the hearing-preserved patients (4.9 [+ or -] 5 cm3) and the hearing-improved patients (3.9 [+ or -] 3.6 cm3).
Such condition could be due to non-malformed cochlea, and promontory cochloestomy is necessary.
OHCs are the most sensitive and susceptible sensory cells of the cochlea to overexposure to noise.
The drum then vibrates the three tiny bones (ossicles) in the middle ear space, which in turn press on a tiny window in the cochlea. The fluid- filled cochlea, in turn, transmits those now-amplified vibrations to move minute projections on sound-sensing hair cells, which convert vibrations to nerve impulses.
The round window and apex of the cochlea were opened to provide access to the fixative.
The sectioned cochlea tissues were used for TUNEL assay and 4HNE staining.
Previous studies have demonstrated a wide distribution of adenosine receptors in the mammalian cochlea, including chinchillas and rats [18, 19].
For sound to reach the inner ear it has to travel through the external ear canal, cross the middle ear, and enter the hearing organ (the cochlea) in the inner ear.
Because of a better understanding of the regenerative failure of the mammalian cochlea and re-epithelization of the non-mammalian auditory epithelium following injury, new approaches have been introduced for the treatment of hearing loss.
A CT scan is taken to evaluate the status of the cochlea and to establish the presence of a patent cochlea or mondini dysplasia, a common cavity, an ossified cochlea and enlarged vestibular aqueduct some cases an MRI is used, in children and young adults speech and language evaluation finally a psychosocial evaluation is completed.