What acts like a funnel, vibrates, sends messages to the brain using waves, and helps to keep you balanced? If you guessed the ear, then you are correct!

The ear is comprised of three sections—the outer, middle and inner ear. Each section has a very important job to perform, allowing us to hear a car coming, someone calling our name, or even the soft purr of a kitten.

“Hear” is how it works. The outer ear is made up of cartilage called the pinna or auricle. This is the part of the ear people see. The auricle functions as a funnel to your inner ear. The auricle collects sounds and sends them down the ear canal. For example, have you ever cupped your hand around your ear to hear a faint sound? Your hand made the “funnel” bigger! The auricle also protects the ear canal, which is where earwax is produced. Earwax serves to keep the ear canal free from dirt and to protect against infections.

The middle ear is where sound waves are converted into vibrations to be sent to the inner ear. The eardrum is a thin semitransparent piece of skin (stretched tight, similar to a drum) located in the middle ear. It is a separator between the outer ear and the middle ear. Also located in the middle ear are the three smallest and most delicate bones in your body! They are the malleus, incus and stapes—together they are called the ossicles.

Let’s look at each of these bones: The malleus is attached to the eardrum and is Latin for “hammer”; the incus is attached to the malleus and is Latin for “anvil”; the stapes is the smallest bone and is attached to the incus. It is Latin for “stirrup.” These are all named after what they resemble.

The middle ear receives sound waves from the outer ear, which causes the eardrum to vibrate. When the eardrum begins to vibrate, it moves the ossicles from the malleus to the incus to the stapes. This helps move the sound into the inner ear, where it is sent to the brain.

On to the inner ear—the vibrations sent from the eardrum through the ossicles enters the cochlea. The cochlea is a small and spiral shaped tube filled with a liquid—similar to a snail shell. When the ossicles begin vibrating, the liquid in the cochlea is set to motion and begins to create waves. There are also microscopic cells covered with hair that begin to move when the cochlea receives vibrations. These hairs create a nerve signal that the brain understands as sound. The brain puts the signal together—and you hear your mom calling your name!

How do our ears help keep us balanced? In the inner ear there are three small loops called semicircular canals. They are located above the cochlea. Similar to the cochlea, they have microscopic hairs and are filled with liquid. So, when you move your head, it moves the liquid and hairs in the semicircular canals. This, in turn, sends a nerve signal to your brain; then your brain translates that into what position your head is in; then your brain sends the message to the muscles needed to support your head in that position.

As children, we all loved to spin around as fast as we could. When we stopped, we were dizzy and may have fallen over. Why is that? As mentioned above, the signal goes to the brain that your head is moving. However, when you stop, the liquid and hairs in the semicircular tubes are still moving. This makes you dizzy and causes you to lose your balance. Once the liquid stops moving, your brain finally gets the signal that you are no longer moving, and you regain your balance.

When you stop and think about all that needs to occur to allow us to hear sounds, it makes you appreciate the awesome and amazing things that God created to happen in our body!

Source: www.kidshealth.org; Fundamentals of Anatomy & Physiology by Frederic Martini, 4th edition.