Hair cells

Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates. Through mechanotransduction, hair cells detect movement in their environment. In mammals, the auditory hair cells are located within the spiral organ of Corti on the thin basilar membrane in the cochlea of the inner ear. They derive their name from the tufts of stereocilia called hair bundles that protrude from the apical surface of the cell into the endolymph fluid.

Structure

Hair cells are columnar cells, each with a bundle of 100-200 specialized cilia on the apical surface, called stereocilia. These cilia are the mechanosensors for hearing. Lightly resting atop the longest cilia is the tectorial membrane, which moves back and forth with each cycle of sound, tilting the cilia and allowing electric current into the cell.

Function

Hair cells, located in the cochlea, are responsible for converting auditory signals into electrical signals, which can be interpreted by the brain. They do this through a process called mechanotransduction.

Mechanotransduction

Mechanotransduction is the process by which the mechanical force of sound waves is converted into electrical signals by hair cells. This process involves the flow of ions through transduction channels that are opened by the deflection of the stereocilia.

Clinical significance

Damage to hair cells usually results in decreased hearing sensitivity, also known as sensorineural hearing loss. Exposure to loud sounds can overload the hair cell and cause cell death. Once a hair cell is lost, it will never grow back, leading to permanent hearing loss.

See also

• Inner ear
• Stereocilia
• Tectorial membrane
• Sensorineural hearing loss

References

Hair cells Resources
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