Hearing protective equipment selection knowledge? The structure of the auditory system

When we are exposed to noise, it's essential to protect our hearing. But what exactly is noise? Simply put, noise refers to any sound that is unwanted, annoying, or irritating. It is a type of sound caused by the vibration of objects. To assess whether a sound might harm our ears, two key factors are considered: frequency and intensity.

Frequency refers to how many vibrations a sound wave makes in one second, measured in Hertz (Hz). You can think of frequency as the pitch of a sound. High-frequency sounds are sharp and high-pitched, while low-frequency sounds are deep and rumbling.

Intensity, on the other hand, measures how strong or loud a sound is, typically expressed in decibels (dB). It reflects the pressure of the sound waves. In daily life, we perceive intensity as volume—some sounds are soft, while others are loud and overwhelming.

When either frequency or intensity becomes too high, it can turn into harmful noise. The damage noise causes to our bodies depends on several factors, such as how long we are exposed to it. The longer the exposure, the greater the risk of hearing loss and other health issues.

Noise can come in different forms—continuous, fluctuating, or pulsating. The closer you are to the source, the more dangerous it becomes. Additionally, individual sensitivity to noise varies, and pre-existing conditions like ear infections or inflammation can make people more vulnerable.

To better understand how sound affects our hearing and overall health, it's important to learn about the structure of the ear and how we process sound. The human ear is a complex and delicate organ that converts sound waves into nerve signals, which are then interpreted by the brain.

The ear has natural defenses, such as earwax (cerumen) in the ear canal, which helps trap dust and debris. However, it lacks a built-in mechanism to protect against loud noises. This is why using ear protection, like earplugs or earmuffs, is crucial in noisy environments.

The auditory system is divided into three main parts:

1. The outer ear includes the pinna, ear canal, and eardrum. It collects sound waves and channels them toward the eardrum. When sound waves hit the eardrum, it vibrates and sends the movement to the middle ear.

2. The middle ear contains three tiny bones called ossicles—the malleus, incus, and stapes. These bones amplify the vibrations from the eardrum and pass them to the inner ear.

3. The inner ear consists of the cochlea and the semicircular canals. The cochlea, filled with fluid and lined with hair cells, plays a critical role in hearing. When vibrations reach the cochlea, they cause the fluid to move, stimulating the hair cells, which then send electrical signals to the brain via the auditory nerve.

It's important to note that once the hair cells in the cochlea are damaged, they cannot regenerate. At birth, humans have approximately 40,000 of these cells. Over time, factors like illness, injury, certain medications, and even loud snoring can gradually reduce their number, leading to permanent hearing loss.

Protecting your hearing is not just about avoiding loud noises—it’s also about understanding how your ears work and taking proactive steps to preserve your hearing for life.

China Labor Insurance Network