Organ of Corti

Organ of Corti
Organ of Corti
Cochlea-crosssection.svg
A cross section of the cochlea illustrating the organ of Corti.
Organ of corti.svg
Section through the spiral organ of Corti. Magnified.
Latin organum spirale
Gray's subject #232 1056
MeSH Organ+of+Corti

The organ of Corti (or spiral organ) is the organ in the inner ear of mammals that contains auditory sensory cells, or "hair cells."

The organ was named after the Italian anatomist Marquis Alfonso Giacomo Gaspare Corti (1822–1876), who conducted microscopic research of the mammalian auditory system.

Contents

Structure and function

See also: Stereocilia (inner ear)

The organ of Corti has highly specialized structures that respond to fluid-borne vibrations in the cochlea with a shearing vector in the hairs of some cochlear hair cells. It contains between 15,000-20,000 auditory nerve receptors. Each receptor has its own hair cell. The shear on the hairs opens non-selective transduction ion channels that are permeable to potassium and calcium, leading to hair cell plasma membrane depolarization, activation of voltage-dependent calcium channels at the synaptic basolateral pole of the cells which triggers vesicle exocytosis and liberation of glutamate neurotransmitter to the synaptic cleft and electrical signaling to the auditory cortex via spiral ganglion neurons. The pinna and middle ear act as mechanical transformers and amplifiers, so that by the time sound waves reach the Organ of Corti, their pressure amplitude is 22 times that of the air impinging on the pinna. The Organ of Corti can be damaged by excessive sound levels, leading to noise-induced health effects. The Organ of Corti is the structure that transduces pressure waves to action potentials.

Hearing loss

Main article: Hearing impairment

The most common kind of hearing impairment, sensorineural hearing loss, includes as one major cause the reduction of function in the organ of Corti. Specifically, the active amplification function of the outer hair cells is very sensitive to damage from exposure to trauma from overly-loud sounds or to certain ototoxic drugs. Once outer hair cells are damaged, they do not regenerate, and the result is a loss of sensitivity and an abnormally large growth of loudness (known as recruitment) in the part of the spectrum that the damaged cells serve.[1]

Additional images

  • Transverse section of the cochlear duct of a fetal cat.

  • Diagrammatic longitudinal section of the cochlea.

  • Floor of ductus cochlearis.

  • Limbus laminæ spiralis and membrana basilaris.

  • Section through the spiral organ of Corti. Magnified.

Notes

  1. ^ Robert A. Dobie (2001). Medical-Legal Evaluation of Hearing Loss. Thomson Delmar Learning. ISBN 0769300529. http://books.google.com/books?id=7dLVJDTUfdAC&pg=PA27&dq=%22outer+hair+cells%22+%22organ+of+corti%22+%22hearing+loss%22#PPA29,M1. 

References

  • Corti A (1851) "Recherches sur l'organe de Corti de l'ouïe des mammifères". Z wiss Zool 3: 1-106.
  • Pritchard U. "On the organ of Corti in mammals". 2 March 1876, Proceedings of the Royal Society of London, volume 24, pp. 346–52 OCLC 1778190

External links

v · d · eSensory system: Auditory and Vestibular systems (TA A15.3, TH 3.11.09, GA 10.1029)
Outer ear

Pinna (Helix, Antihelix, Tragus, Antitragus, Incisura anterior auris, Earlobe) • Ear canal • Auricular muscles

Eardrum (Umbo, Pars flaccida)
Middle ear

Labyrinthine wall/medial: Oval window · Round window • Secondary tympanic membrane • Prominence of facial canal • Promontory of tympanic cavity

Membranous wall/lateral

Mastoid wall/posterior: Mastoid cells • Aditus to mastoid antrum • Pyramidal eminence

Carotid wall/anterior

Tegmental wall/roof: Epitympanic recess

Jugular wall/floor
Stapedius · Tensor tympani
Bony part of pharyngotympanic tube · Cartilage of pharyngotympanic tube (Torus tubarius)
Inner ear/
(membranous labyrinth,
bony labyrinth)
General cochlea
Perilymphatic space

Reissner's/vestibular membrane • Basilar membrane

Endolymph • Stria vascularis • Spiral ligament

Organ of Corti: Stereocilia • Tectorial membrane • Sulcus spiralis (externus, internus) • Spiral limbus
Cells

M: EAR

anat(e/p)/phys/devp

noco/cong, epon

proc, drug(S2)

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Look at other dictionaries:

  • Organ of Corti — Organ Or gan, n. [L. organum, Gr. ?; akin to ? work, and E. work: cf. F. organe. See {Work}, and cf. {Orgue}, {Orgy}.] [1913 Webster] 1. An instrument or medium by which some important action is performed, or an important end accomplished; as,… …   The Collaborative International Dictionary of English

  • organ of Corti — organ of Cor·ti kȯrt ē n a complex epithelial structure in the cochlea that in mammals is the chief part of the ear by which sound is directly perceived and that rests on the internal surface of the basilar membrane and contains two spiral rows… …   Medical dictionary

  • organ of Corti — [kôrt′ē] n. the spiral structure inside the cochlea of the inner ear, containing the hair cells that are sensitive to sound waves …   English World dictionary

  • organ of Corti — spiral organ the sense organ of the cochlea of the inner ear, which converts sound signals into nerve impulses that are transmitted to the brain via the cochlear nerve. [A. Corti (1822–88), Italian anatomist] …   The new mediacal dictionary

  • organ of Corti — the sense organ of the cochlea of the inner ear, which converts sound signals into nerve impulses that are transmitted to the brain via the cochlear nerve. A. Corti (1822 88), Italian anatomist …   Medical dictionary

  • organ of Corti — noun the hearing organ of the inner ear; contains receptors that respond to sound waves • Hypernyms: ↑organ of hearing • Part Holonyms: ↑cochlea • Part Meronyms: ↑hair cell …   Useful english dictionary

  • organ of Corti — Etymology: Alfonso Corti died 1876 Italian anatomist Date: 1867 a complex epithelial structure in the cochlea that rests on the internal surface of the basilar membrane and in mammals is the chief part of the ear by which sound is directly… …   New Collegiate Dictionary

  • organ of Corti — /kawr tee/ Anat., Zool. a structure in the cochlea of a mammal, consisting of hair cells that serve as receptors for auditory stimuli. [1880 85; named after A CORTI] * * * …   Universalium

  • organ of Corti — n. section of the cochlea that includes the special sensory receptors for hearing (name after Alfonso Corti) …   English contemporary dictionary

  • organ of Corti — noun Anatomy a structure in the cochlea of the inner ear which produces nerve impulses in response to sound vibrations. Origin C19: named after the Italian anatomist Alfonso Corti …   English new terms dictionary

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