Ears

Listen. Whatever you're hearing — the hum of a computer, your kids playing, a car going by — is thanks to your ears.

Hearing is their main job, but it's not all our ears do. These delicate organs also need care and protection, so let's take a look at how they work and what conditions and problems can affect them.

All About Ears
There's a lot more to an ear than what you see on the side of your head. The ear is made up of three different sections that work together to collect sounds and relay them to the brain: the outer ear, the middle ear, and the inner ear.

The outer ear, the part that is visible on the side of your head, is called the pinna or auricle. It's made of tough cartilage covered by skin. The pinna's main job is to gather sounds and funnel them to the ear canal, which leads to the middle ear. The pinna, which includes the earlobe, is the part that people pierce to wear earrings.

The ear canal, the hollow passage that leads to the eardrum, is also part of the outer ear. Glands in the skin lining the ear canal produce earwax, which protects the canal by cleaning out dirt and helping to prevent infections.

The middle ear is an air-filled cavity about the size of a pea. It turns sound waves into vibrations and delivers them to the inner ear. The middle ear is separated from the outer ear by the eardrum, or tympanic membrane, a thin, cone-shaped piece of tissue stretched tight across the ear canal.

To hear properly, the pressure on both sides of your eardrum needs to be equal. When you go up or down in elevation, the air pressure changes and you may feel a popping sensation as your ears adjust. Ears are able to adjust thanks to the narrow Eustachian tube that connects the middle ear to the back of the nose and acts as a sort of pressure valve, opening to keep the pressure equalized on both sides of the eardrum.

The middle ear also includes the three smallest bones in the body, located just past the eardrum and collectively known as the ossicles. The ossicles consist of:

the malleus (Latin for "hammer"), which is attached to the eardrum

the incus ("anvil"), which is attached to the malleus

the stapes ("stirrup"), which is attached to the incus and is the smallest bone in the body

The inner ear consists of two tiny organs called the cochlea and the semicircular canals. The snail-shaped cochlea act as a sort of microphone, converting the vibrations from the middle ear into nerve impulses that travel to the brain along the cochlear nerve, also known as the auditory nerve.

The semicircular canals look like three tiny, interconnected tubes sticking out in loops from the top of the cochlea. It's their job to help you balance. The canals are filled with fluid and lined with tiny hairs. When your head moves, the fluid in the canals sloshes around, moving the hairs. The hairs send this position information as impulses through the vestibular nerve to your brain. The brain interprets these impulses and sends messages to the muscles that help keep you balanced.

When you spin around and stop, the reason you feel dizzy is because the fluid in your semicircular canals continues to slosh around for awhile, giving your brain the idea that you're still spinning even when you aren't. When the fluid stops moving, the dizziness goes away.

The cochlear nerve, which is attached to the cochlea and relays sound information to the brain, and the vestibular nerve, which carries balance information from the semicircular canals to the brain, are collectively known as the vestibulocochlear nerve, or 8th cranial nerve.

Balance Disorders

When you think about balance, the role that ears play might not come to mind. But ears are crucial to maintaining balance thanks to their vestibulocochlear nerve. This nerve sends signals to the brain that control hearing (auditory function) and help with balance (vestibular function).

But the ears aren't the only organs that help us balance. Ears, eyes, joints, and muscles work together to keep us steady and upright. When one or more of these systems is out of whack, it can be hard to get around and just function, day to day. The simplest things — like walking, riding a bike, succeeding in school, even playing — can become difficult and frustrating.

Balance disorders are considered uncommon in kids but might be underestimated — kids' symptoms could be misdiagnosed as something else or missed altogether. But resolving kids' balance problems can make a big improvement in their overall quality of life — their ability to play, learn, and feel as happy and healthy as possible.

How Balance Works
To understand balance problems, it's important to understand how balance works normally. Basically, the body relies on three separate systems, each sending nerve impulses to the brain:

In the neck, torso, leg joints, and feet are pressure sensors that send information to the brain about where the body is in relation to the world (known as proprioception). Messages are sent when we do things like turn our heads, move, and walk on different surfaces.
In the front of the inner ear, or labyrinth, are the cochlea, involved in hearing; in the rear are semicircular canals, which affect balance. Connecting them is the vestibule (with sensory organs known as the utricle and saccule), which affects balance and equilibrium. When we turn our heads rapidly, the liquid in the semicircular canals moves the tiny hairs lining the cochlea, sending a message (through the vestibulocochlear nerve) to the brain about the movement. In less than a second, the brain sends messages to the muscles needed to maintain balance and help the eyes stay focused.
In the eyes, the nerve endings in the retina (at the back of the eye) have light-sensitive cells called rods and cones. When we look at something, light hits the retina, and the rods and cones send electrical signals to the brain through the optic nerve. The brain uses these signals to interpret what we're seeing and create visual images. Each eye gets slightly different images of (and information about) the same object, which aids depth perception (how far away an object is) and is vital to maintaining balance.
If any of these systems isn't working right, it can affect balance.