聴覚

Sound waves are collected by the external ear and amplified through the ear canal. They vibrate the tympanic membrane, causing attached ossicles to move. The ossicles then vibrate the oval window of the cochlea, transferring mechanical energy to fluid within the inner ear structure.

Hair cells are receptors located on the organ of Corti within the cochlea that detect vibrations of the basilar membrane. They transduce mechanical sound waves into electrical neural signals that can be interpreted by the brain, enabling sound perception and auditory awareness.

Frequency of sound waves is perceived as pitch, while amplitude is perceived as loudness. These characteristics are maintained along the primary auditory pathway through the auditory nerve, brainstem, thalamus, and primary auditory cortex, where basic sound properties are identified and perceived.

After the primary auditory cortex identifies basic sound characteristics like pitch, sound information is sent to nearby cerebral cortex areas for higher-level processing. Wernicke's area, which is critical for understanding speech, receives this information for language comprehension and semantic interpretation of auditory input.

Auditory signals travel through the auditory nerve to the cochlear nuclei in the brainstem, then to the inferior colliculus of the midbrain, up to the thalamus, and finally to the primary auditory cortex. This organized pathway preserves sound information at each processing stage.

The cochlea is a coiled inner ear structure containing fluid that moves in response to oval window vibrations. This fluid movement vibrates the basilar membrane, stimulating hair cells on the organ of Corti to transduce mechanical energy into electrical signals for neural transmission.

The ossicles are small bones attached to the tympanic membrane that vibrate when sound waves cause the eardrum to move. These bones transfer and amplify mechanical vibrations to the oval window, efficiently transmitting sound energy from the middle ear to the inner ear structure.