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Information about Organ Of Corti

A cross section of the cochlea illustrating the organ of Corti.
Section through the spiral organ of Corti. Magnified.
Latinorganum spirale
subject #232 1056
MeSH Organ+of+Corti
Dorlands/Elsevier o_06/12596269
The organ of Corti (or spiral organ) is the organ in the inner ear of mammals that contains auditory sensory cells, or "hair cells."

Structure and function

It 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. The Organ of Corti contains between 15,000-20,000 auditory nerve receptors. Each receptor has its own hair cell. The shear on the hairs opens ion channels, leading to neural, electrical signaling to the auditory cortex. The pinna and middle ear amplify sound levels, so that by the time these longitudinal waves reach the Organ of Corti, they are 20 times that of the levels impinging on the pinna. This amplification is partly responsible for the delicacy of the Organ of Corti with respect to excessive sound levels, and helps to understand noise induced health effects.

The discoverer: Alfonso Corti

The organ was named after the Italian anatomist Marquis Alfonso Giacomo Gaspare Corti (1822-1876), who conducted microscopic research of the mammalian auditory system from 1849 to 1851 at the Koelliker laboratory in Würzburg (Germany). He developed new coloring techniques in microscopic anatomy, which enabled him to distinguish and describe individual components inside the highly complex cochlea that had previously been unidentified. In 1851 he was the first to describe the core sensory organ in the mammalian cochlea, the organ of Corti.

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.


Notes

1. ^ Robert A. Dobie (2001). Medical-Legal Evaluation of Hearing Loss. Thomson Delmar Learning. ISBN 0769300529. 

References

  • Corti A (1851) Recherches sur l'organe de Corti de l'ouïe des mammifères. Z wiss Zool 3: 1-106.

External links

 •  • [ e]
Sensory system: Auditory and Vestibular systems
Outer earPinna (Helix, Antihelix, Tragus, Antitragus, Earlobe) • Ear canal
Middle earEardrum • Ossicles (Malleus, Incus & Stapes) • Stapedius • Tensor tympani • Eustachian tube (Torus tubarius)
Inner ear/LabyrinthBony labyrinth (Vestibule) • Membranous labyrinth
Oval window • Helicotrema • Round window
Cochlea: Spiral ganglion • Modiolus • Cochlear duct/scala media (Endolymph, Stria vascularis, Spiral ligament, Organ of Corti) • Scala vestibuli and Scala tympani (Perilymph)
Reissner's/vestibular membrane • Basilar membrane • Tectorial membrane
Organ of Corti: Hair cells • Stereocilia • Sulcus spiralis (externus, internus) • Limbus spiralis
Vestibular systemStatic/translations: Utricle (Macula) - Saccule (Macula, Endolymphatic sac, Endolymphatic duct) - Kinocilium - Otolith
Kinetic/rotations: Semicircular canals (Superior, Posterior, Horizontal) • Cupula • Ampullae (Crista ampullaris)
Brain (auditory)Cochlear nerve VIII → Cochlear nuclei → Superior olivary nuclei → Lateral lemniscus → Inferior colliculi → Medial geniculate nuclei → Primary auditory cortex
Latin}}} 
Official status
Official language of: Vatican City
Used for official purposes, but not spoken in everyday speech
Regulated by: Opus Fundatum Latinitas
Roman Catholic Church
Language codes
ISO 639-1: la
ISO 639-2: lat
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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Elsevier, the world's largest publisher of medical and scientific literature, forms part of the Reed Elsevier group. Based in Amsterdam, the company has substantial operations in the UK, USA and elsewhere.
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The inner ear is the bony labyrinth, a system of passages comprising two main functional parts:
  • the organ of hearing, or cochlea
  • and the vestibular apparatus, the organ of balance that consists of three semicircular canals and the vestibule.

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Mammalia
Linnaeus, 1758

Subclasses & Infraclasses
  • Subclass †Allotheria*
  • Subclass Prototheria
  • Subclass Theria

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Location Cochlea
Function Amplify sound waves and transduce auditory information to the Brain Stem

Morphology Unique (see text)
Presynaptic connections None
Postsynaptic connections
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Stereocilia are mechanosensing organelles of hair cells, which respond to fluid motion or fluid pressure changes in numerous types of animals for various functions, primarily hearing. They are about 5 micrometers in length and share some similar features of microvilli.
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The cochlea is the auditory portion of the inner ear. Its core component is the Organ of Corti, the sensory organ of hearing, which is distributed along the partition separating fluid chambers in the coiled tapered tube of the cochlea.
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Ion channels are pore-forming proteins that help to establish and control the small voltage gradient across the plasma membrane of all living cells (see cell potential) by allowing the flow of ions down their electrochemical gradient.
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The primary auditory cortex is the region of the brain that is responsible for processing of auditory (sound) information.

Function of the Primary Auditory Cortex


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The pinna (Latin for feather) is the visible part of the ear that resides outside of the head (this may also be referred to as the auricle or auricula).

Purpose

The purpose of the pinna is to collect sound.
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The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear.
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Noise health effects, the collection of health consequences of elevated sound levels, constitute one of the most widespread public health threats in industrialized countries. Roadway noise is the main source of environmental noise exposure.
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MeSH D034381 A hearing impairment or hearing loss is a full or partial decrease in the ability to detect or understand sounds.[1] Caused by a wide range of biological and environmental factors, loss of hearing can happen to any organism that perceives sound.
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MeSH D006319 Sensorineural hearing loss is a type of hearing loss in which the root cause lies in the vestibulocochlear nerve (Cranial nerve VIII), the inner ear, or central processing centers of the brain.
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Location Cochlea
Function Amplify sound waves and transduce auditory information to the Brain Stem

Morphology Unique (see text)
Presynaptic connections None
Postsynaptic connections
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sensory system: in this case, vision, for the visual system. ]]

A sensory system is a part of the nervous system responsible for processing sensory information.
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The auditory system is the sensory system for the sense of hearing.

Ear

Main article: Ear

Outer ear

Main article: Outer ear

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The vestibular system, or balance system, is the sensory system that provides the dominant input about our movement and orientation in space. Together with the cochlea, the auditory organ, it is situated in the vestibulum in the inner ear (Figure 1).
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The outer ear is the external portion of the ear.

Pinna, or auricle

The visible part is called the pinna and functions to collect and focus sound waves. Many mammals can move the pinna (with the auriculares muscles) in order to focus their hearing in a certain direction
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The pinna (Latin for feather) is the visible part of the ear that resides outside of the head (this may also be referred to as the auricle or auricula).

Purpose

The purpose of the pinna is to collect sound.
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The prominent rim of the auricula is called the helix. Where the helix turns downward behind, a small tubercle is frequently seen: the auricular tubercle of Darwin.

Additional images



The muscles of the auricula.

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antihelix, also known as the anthelix; this divides above into two crura, between which is a triangular depression, the fossa triangularis.

Additional images



The muscles of the auricula.

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tragus, so called from its being generally covered on its under surface with a tuft of hair, resembling a goat’s beard, "goat" being the origin of the word, from the Greek tragos.
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antitragus.

External links

  • SUNY Labs 30:01-0105
  • Norman/Georgetown lesson3 ( externalear ) (#6)
  • Diagram at bodymodforums.

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On the ear of humans and many other animals, the earlobe (lobulus auriculæ, sometimes simply lobe or lobule) is the soft lower part of the Cory Drosen's ear, similar in composition to the labia, or pinna.
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The ear canal (external auditory meatus, external acoustic meatus), is a tube running from the outer ear to the middle ear. The ear canal extends from the pinna to the eardrum and is about 26 mm in length and 7 mm in diameter.
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The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear.
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The tympanic membrane, colloquially known as the eardrum, is a thin membrane that separates the external ear from the middle ear. Its function is to transmit sound vibrations from the air, conducted through the external acoustic meatus to the ossicles inside the
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The ossicles (also called auditory ossicles) are the three smallest bones in the human body. They are contained within the middle ear space and serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea).
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