Hearing protection 101: The anatomy of the ear and how it functions

Because sound is not a visible threat, occupational noise is a danger that is often underestimated in the workplace. Injuries such as hearing loss happens gradually and silently, which is vastly different than other hazards encountered on the job. But with nearly 22 million workers exposed to hazardous occupational noise per year, hearing loss is the third most chronic physical condition in the U.S. – and unlike other injuries, once your hearing is gone, it’s not coming back.

To better recognize how harmful noise can be in the short and long term, understanding how the human ear is structured and how our sense of hearing functions can help you see just how important proper hearing protection can be in the workplace, every single day.

How your ears hear sound

Hearing allows us to identify and recognize objects in the world based on the sound they produce, making communication using sound possible. The way your ears perceive sound can affect your health, both in hearing loss and in related issues, which is why hearing protection is so vital.

So how does the ear hear? Hearing depends on a series of complex steps that change sound waves in the air into electrical signals.

Structure of the ear

All the structures of the ear work together to help you hear, starting from the outside. The outer portion of the ear is formed by the pinna, which is connected directly to the eardrum via the ear canal. The ear canal leads to the eardrum and is connected to the ossicular chain, which consists of three small bones: the malleus, incus, and stapes.

All of these hearing “aids” are located in the middle ear, where the stapes footplate is connected to the oval window of the cochlea. Here, signals are then transmitted to the auditory nerve.

The function of the auditory nerve

For hearing to be possible, it is important for sound to be modified by passing through air into the inner ear fluid within the cochlea. Since fluids are far denser than air, we would perceive all noise as significantly quieter without this active adjustment.

Here’s how you hear:

1. Sound enters via the outer ear and travels down into the ear canal before reaching the eardrum.
   
2. Here, vibrations are then directly passed on to the malleus bone. A chain reaction follows, with the malleus sending the signal to the incus, where it is then passed on to the stapes and the stapes footplate. Since the acoustic signal gradually travels from the eardrum's relatively large surface area to the very small stapes footplate, the signal is amplified step by step.
3. Next, the inner ear fluid is made to vibrate. Many little hair cells called stereocilia act as sensory receptors within the cochlea with two important functions: strengthening the sound wave even further and being responsible for our ability to differentiate between different frequencies.
4. Connected to the cochlea is the cochlear (or auditory) nerve, which sends these signals to the brain, where they are experienced as sound.

This set of events enables us to understand speech and distinguish various letters or words. The way your ears perceive sound can affect your health, both in hearing loss and in related issues, if sound levels are high enough.

The function of hearing - and the effects of hearing impairments on people

Our hearing is tasked with relaying external noises to our brains so we can respond accordingly. If that function is limited – for example, due to a hearing impairment – this can have unpleasant or even severe consequences both at work and at home. The unfortunate side effect is that hearing loss affects all areas of your life.

Take these examples below:

HexArmor® can help

There are several factors to consider when choosing which earplug or earmuff technology is right for you, which is why HexArmor® offers a variety of hearing safety information as well as varying levels of hearing protection so you can be properly protected for your specific application and environment.

Let us know if you need help finding what you need or if you're ready to start a trial - our Solution Specialists are ready to work with you. Call 1-877-MY ARMOR or send us a message.

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