The ear is the organ of hearing and balance. The human ear is capable of receiving sounds with a frequency of 16 to 22000 Hz (vibrations per second), with an intensity of 0 to 120 dB (decibels). In the outer and middle ear, sound conduction takes place, and in the inner ear, sound is received. Further emission of the auditory stimulus passes through the auditory nerve and auditory canal to the cerebral cortex in the temporal lobe. Depending on the location of the lesion, the hearing loss is divided into:
- conductive hearing loss (damage in the outer and middle ear).
- hearing loss, which is characterized by:
- cochlear hearing loss (damage to sensory cells in the cochlea),
- nerve hearing loss (damage to nerve fibers of the VIII nerve),
- central hearing loss (damage can affect any part of the auditory pathway in the brain).
Cochlear and nervous hearing can be one-ear, while the central one is always two-ear due to the intersection of nerve fibers in the course of the auditory canal.
The atria, together with the hearing organ in the inner ear, is an integral part of the balance system alongside the organ of vision, deep sense receptors and centres located in the brainstem and in the cerebellum. The vestibular organ is involved in the process of maintaining body posture and orientation in space. Its function is determined by the interaction of the peripheral and central nervous system.