Ear Organ of Corti - Condensed Version

Summary

Key Points

• The organ of Corti, located within the spiral, three-chambered cochlea, serves as the receptor organ of hearing. 0:08
• It extends for approximately 2.5 turns around a bony pillar called the modiolus and is housed within the scala media, which is filled with endolymph. 0:25
• Key structures within the organ of Corti include the tectorial membrane, basilar membrane, and two types of hair cells: inner and outer. 0:43
• Inner hair cells account for 95% of afferent fibers, while outer hair cells primarily receive efferent input, and tip links connect stereocilia to amplify mechanical forces. 1:05
• Sound enters the cochlea when the stapes transfers force from the tympanic membrane to the oval window, with high frequencies encoded at the base and low frequencies at the apex, establishing a tonotopic map. 1:40
• The manner in which the basilar membrane vibrates in response to sound is crucial, creating a shearing force between the tectorial and basilar membranes. 2:02
• A unique potassium concentration gradient, with high potassium at the hair cell's apex and low at its base, facilitates both depolarization (potassium influx) and repolarization (potassium efflux). 2:44
• Hair cells, positioned between these membranes, are stimulated by this shearing force, converting mechanical vibrations into neural impulses. 2:55
• These neural impulses are subsequently transmitted to the brain, which then interprets them as sound. 2:59