How does hearing work?

Whether a friend whispers into your ear or a jet is flying in the sky, sound is all around us. Our ears enclose the three smallest bones in our body, change sound waves in the air to electrical signals in the brain, and help us communicate and connect with our loved ones. So, how exactly does this happen?

Our ears have three parts: the outer, middle, and inner ear. The first step in hearing is collecting sounds. Our outer ear, or Pinna, collects the sound to travel inside your ear canal. Our Pinna is also responsible for locating sounds. The sound waves travel into the ear canal until they reach the eardrum. The eardrum is at the end of the ear canal. This is where your middle ear starts.

The eardrum passes vibrations through the three middle ear bones called the Ossicles (Malleus, Incus, Stapes or sometimes commonly referred to as the “hammer, anvil, and stirrup”). These three bones form a chain from the eardrum to the inner ear. The eardrum moves back and forth when sounds hit it. The eardrum will move faster or slower depending on how loud, or what pitch, the sound is. This sends the chain into motion and then sends a signal to the inner ear.

The inner ear, or Cochlea, is shaped like a snail and filled with fluid and hair cells. There are thousands of tiny hair cells (not to be confused with the hair on top of your head) housed inside the Cochlea. The hair cells change the vibrations into electrical signals that are sent to the brain through the hearing nerve. The brain then tells you that you are hearing a sound and what that sound is. Your inner ear also helps you control your balance. The parts of your inner ear that help with balance share the same space and fluid as the cochlea.

The human body is a network of pairs: two eyes, ears, nostrils, arms, hands, feet, and legs. The brain uses these pairs to coordinate and maximize how the body works. Our ears work as a duo. We have two ears to locate sound, discriminate volume, as well as enjoy a better quality of sound like hearing in “stereo”. Being able to hear with both ears makes it easier to enjoy the sounds of life.