kuulohermosta

Kuulohermo, also known as the auditory nerve or the eighth cranial nerve (CN VIII), is a crucial part of the auditory system responsible for transmitting sound information from the inner ear to the brain. It is a sensory nerve composed of two main functional divisions: the cochlear nerve and the vestibular nerve.

The cochlear nerve is responsible for hearing. It receives auditory signals from the hair cells within the cochlea, the spiral-shaped structure of the inner ear. These hair cells transduce mechanical vibrations into electrical impulses. The cochlear nerve then carries these impulses along its fibers, which are bundled together, towards the brainstem.

The vestibular nerve, on the other hand, is responsible for balance and spatial orientation. It originates from the vestibular labyrinth in the inner ear, which includes the semicircular canals and the otolith organs. These structures detect head movements and position relative to gravity. The vestibular nerve transmits this information to the brainstem and cerebellum, aiding in maintaining equilibrium and coordinating movements.

The auditory and vestibular nerves share a common pathway as they exit the inner ear and enter the brainstem. Within the brainstem, the auditory information is processed through a series of nuclei before reaching the auditory cortex in the temporal lobe of the brain, where it is interpreted as sound. Similarly, vestibular information is processed to control eye movements and postural reflexes. Damage to the kuulohermo can result in hearing loss, tinnitus, vertigo, and balance problems.