tectoriakalvoa

The tectorial membrane (Finnish: tektorialkalvo) is a gelatinous extracellular matrix in the cochlea of the inner ear. It lies in the scala media, over the organ of Corti, and is anchored medially to the spiral limbus, with fibrils extending laterally over the hair cells. The inner edge attaches to the spiral limbus, while the lateral edge overlies the stereocilia of the outer hair cells; the inner hair cell stereocilia contact the membrane indirectly during transduction.

Structure and composition: The membrane is secreted by the supporting cells of the organ of Corti and consists mainly of collagen (primarily type II) and non-collagenous glycoproteins such as otogelin and beta-tectorin, along with proteoglycans. Its mechanical properties are viscoelastic and can vary with development and aging.

Function: The tectorial membrane plays a key role in auditory transduction by coupling basilar-membrane motion to the hair-cell stereocilia. Outer hair cell stereocilia are embedded in the membrane, allowing shear forces generated by cochlear motion to deflect the hair bundles and enhance sensitivity and frequency selectivity. The membrane thus contributes to cochlear amplification and the overall mechanical tuning of the inner ear.

Development and clinical relevance: The tektorialkalvo forms during cochlear development and matures after birth. Genetic mutations affecting its components, such as otogelin or beta-tectorin, or age-related changes in its structure, can influence hearing and may contribute to hearing impairment. Changes in its stiffness or attachment can alter cochlear mechanics and auditory perception.