How does sound come into our ears

Ears have more functions than you think. These functions are the basis of understanding voice, listening to music and voice, and also can identify the direction. As long as you close your eyes and listen attentively, you can understand that directional hearing is a very important indicator of familiarity with the environment. Having healthy listening can ensure that you can enjoy a rich life anytime, anywhere, and you will have more in-depth experience under the premise of safety. To understand hearing loss in depth, we must first understand how listening works. The ear is a simple but wonderful organ, which can transform the sound waves in the air into various detailed sounds and transmit them to the brain, and also can convey the feelings of the outside world to your heart.

Our ears are highly complex organs, mainly composed of three parts: the outer ear, the middle ear and the inner ear.

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The operation of hearing

Our ears collect sound, conduct it mechanically, convert neural signals to produce hearing, so that the brain can recognize sound, such as music, dog barking, flushing, ringing, speaking, etc. in one go.

External ear

It refers to the ears we usually see, including the auricle and the ear canal; sound refers to the eardrum through which sound waves are transmitted to our ears through the air, collected by the auricle and transmitted to the inner ear through the ear canal. Eardrum is a circular and elastic membrane. When sound comes in, eardrum will vibrate.

Middle ear

This is an air filled cavity separated by the eardrum and the outer ear. There are three auditory ossicles in the middle ear: the malleus, the incus and the stapes. They are also the smallest three bones in human structure. Auditory ossicles are the conduction bridge between the eardrum and the inner ear. The mechanical vibration produced by the auditory ossicles chain, which is made up of three auditory ossicles, will make the liquid in the cochlea fluctuate, and then stimulate the nerve fibers to produce nerve electrical signals.

Inner ear

The inner ear mainly refers to the cochlea, the snail or spirochaea from Greek. It is named after the appearance of a snail. The inner ear is full of liquid. When listening to the voice coming from a small bone, the liquid in the cochlea will generate waves, stimulate the nerve fiber hair cells to generate nerve electrical signals, and transmit these signals to the auditory nerve, then upload them to the brain, and interpret these signals into sound 。

Loudness

The difference is the loudness and distance of these sources. By listening, we can also accurately determine the position and direction of the sound source, which is called listening position discrimination.

The intensity of sound is measured in decibels (DB). Decibel represents the unit of relative intensity of sound. We define the weakest sound that can be sensed by ordinary people’s ears as 0 decibel, which is also the smallest sound that can be heard by young people with good hearing. The volume of daily conversation is between 50 decibels and 60 decibels. 100 decibels has made people’s ears slightly painful. Normal people’s ears will not feel it at 120 dB SPL Comfortable, 140 dB SPL will feel pain.

Once a person is exposed to loud environment for a long time, the sensitive inner ear structure will be damaged, resulting in noise induced hearing loss (NIHL)