MAIN Health The Human Body Ears

Ears are the sensory organ responsible for interpreting the world at the speed of sound.

From a child's laugh to the blare of a police siren, sounds travel from the ear to the brain that serve to either alarm, annoy or delight us.

Built for sound

Sound is actually a kind of energy that moves through the air (and many other substances, like water, for instance) via waves of pressure - hence the name sound waves.

The ear's unique construction, meanwhile, can be compared to acoustics of a Roman forum or fine concert hall - perfectly attuned to "catching the waves" on their way to the brain.

How the ear works

The ear has three main parts: the outer, middle and inner ear.

Sound enters through the outer ear canal and reaches the middle ear where it causes the ear drum to vibrate, setting off vibrations to the nearby hammer, anvil and stirrup - the three smallest bones in the body - and transfers them to the inner ear. The vibrations next move through fluid in the inner ear (cochlea) which bends tiny hair cells - somewhat like wind through a wheat field - triggering nerve signals to the brain which in turn interprets them as sounds we hear everyday.

Ears and equilibrium

While ears are a major contributor to helping us make our way in the world, hearing is not their only function. Another important role the ear plays is as a major contributor to our sense of body position. The fluid contained within the inner ear works as a kind of balancing mechanism for the entire body, and any disruption (i.e., from an earache or inner ear infection) may cause us to feel awash in confusion and unsteady on our feet until we recover.

Keeping ears healthy - what not to do

While they are delicate instruments, ears usually do not require much looking-after. More often its is simply a case of keeping them safe from abuse.

Of course, this is sometimes not as easy as it sounds in our modern world.

Extremely loud noises, for instance, can have sudden damaging effects, although more commonly it is constant exposure to high-decibel noise, from DVD or iPod earbuds for example, that builds up slight damage over time and eventually leads to hearing loss.

While good hygiene plays an important part in keeping ears healthy, over-cleaning may do more harm than good!

Ear wax is there to protect the inner workings of the ear, and so constantly removing it exposes the ear to possible damage. Trying to clean out the ear may also only serve to compact the wax further in the ear, resulting in eardrum damage or infection. The best solution is to clean whatever wax makes it far enough out that it can be reached with a damp cloth, and leave the rest in the ear to do its job.

More about the human ear around the Web:

How Hearing Works - Popular guide on the workings of the human ear and how it transfers sound to the brain with related diagrams and animated illustrations.

A Primer on Ear Anatomy - Information on the outer, middle and inner ear listing parts and bones with color illustrations, and more on common causes of hear loss.

Your Ears - Kid-friendly information on how they work, with a list of ear parts and their functions, a discussion on why ears "pop" on airplanes, and related resources and articles on how to avoid damage and hearing loss.

HyperPhysics Concepts - Sound and Hearing - Get a college education with this intriguing online course explaining human hearing, sound transmission, acoustics, decibel measurement and related topics.