The sound we hear is actually a vibration wave with a certain frequency range emitted by a certain sound emitter _ sound waves. The human ear is like a satellite receiver that receives sound waves and converges them to the external ear canal, then to the eardrum, causing the eardrum to vibrate, so that the acoustic energy of the sound waves is transformed into mechanical energy, and the vibration of the eardrum can drive the auditory tuberosity connected to it; and the activity of the auditory tuberosity can vibrate the oval window membrane, the gateway to the inner ear, so that the lymphatic fluid in the inner ear vibrates, thus causing the basilar membrane of the inner ear to vibrate At this point, the mechanical energy is transformed into a biological signal, and this electrical signal converges in the auditory nerve and is then transmitted through the auditory nerve to the auditory center in the brain, at which point the person really “hears” the sound. Listen to the center is like an intelligence institute, will come to the bioelectrical signals for classification, numbering and analysis, the brain at this time to understand what is the meaning of the received sound waves, and then, in order to respond. Although we talk a lot, in fact, this process is completed in a very short period of time, only a few thousandths of a second, they are simply not aware of. As we know from physics, it takes a lot of energy to push the lymphatic fluid in the inner ear to vibrate, and the energy of sound waves is very small, so how is this process accomplished? This is mainly due to the clever construction of the middle ear, which allows this task to be accomplished. It turns out that the tympanic membrane, the auditory tuberosity, and the oval window membrane are linked together. The part of the tympanic membrane that can vibrate has an area of about 55 square millimeters, while the oval window membrane is only 3.2 square millimeters, a difference of about 17 times, which means that the force transmitted from the outer ear to the inner ear is increased by about 17 times. In addition, from the auditory tuberosity is like a lever that increases the energy by another 1.3 times, so that the sound waves are actually amplified by about 22 times (1.3×17=22) when they are transmitted from the outer ear to the inner ear. Thus, the middle ear cavity acts as an amplifier. Obstruction of sound at any point before it reaches the inner ear can cause hearing loss, and this hearing loss is called conductive deafness. How do people distinguish between different tones of sound in the natural world, which is so varied? This is mainly due to the action of the hair cells in the basilar membrane. There are many types of hair cells, some specializing in the perception of high tones and some in the perception of low tones; together with the analysis and collation of the hearing center, people are able to distinguish different tones. The hair cells are very sensitive, so if they are stimulated by sound for a long time, especially noise, they will become fatigued and their function will be impaired, or even wither, and lose their function, thus causing deafness; in addition, the auditory nerve is like a wire that carries bioelectric signals, and if there is an interruption at a certain point, the person cannot hear the sound, and this kind of deafness is called neurological deafness. This kind of deafness is called neurogenic deafness. We often say that neurogenic deafness actually refers to the above two cases, so it should be accurately called sensorineural deafness.