知识百科：为什么巨大的声响会导致耳鸣

英语自学网

　　还记得上次去听摇滚音乐会，或者看烟花展之后，你的耳朵一直出现奇怪的声响吗?一时间，你听不到周围的任何声音，而你的脑中一直出现嗡嗡声，好像你的耳朵都要爆炸了。这就是耳鸣。那么，它是怎么产生的呢?下面这篇文章将为你解释这个现象。
        　　Noise levels louder than a shouting match can damage parts of our inner
ears called hair cells. Hair cells act as the gatekeepers of our hearing. When
sound waves hit them, they convert those vibrations into electrical currents
that our auditory nerves carry to the brain. Without hair cells, there is
nothing for the sound to bounce off, like trying to make your voice echo in the
desert.
        　　Hair cells reside in the inner ear inside the shell-shaped cochlea(耳蜗).
Bundles of hair-like extensions, called stereocilia(纤毛), rest on top of them.
When sound waves travel through the ears and reach the hair cells, the
vibrations deflect off the stereocilia, causing them to move according to the
force and pitch of the vibration. For instance, a melodic piano tune would
produce gentle movement in the stereocilia, while heavy metal would generate
faster, sharper motion. This motion triggers an electrochemical current that
sends the information from the sound waves through the auditory nerves to the
brain.
        　　When you hear exceptionally loud noises, your stereocilia become damaged
and mistakenly keep sending sound information to the auditory nerve cells. In
the case of rock concerts and fireworks displays, the ringing happens because
the tips of some of your stereocilia actually have broken off. You hear those
false currents in the ringing in your head, called tinnitus(耳鸣). However, since
you can grow these small tips back in about 24 hours, the ringing is often
temporary.