Anatomy: HOW WE HEAR
Hearing is a vital part of our five senses. It is a complex process of picking up sound and attaching meaning to it. The ability to hear is critical to understanding the world around us.
The human ear is a fully developed part of our bodies at birth and responds to sounds that are very faint as well as sounds that are very loud. Even while still in the mother’s womb, infants respond to sound.
So, how do we hear?
The ear is made up of three different sections: the outer ear, the middle ear, and the inner ear. These parts all work together so you can hear and process sounds. Let’s look into these three complex parts of our hearing system in more detail.
The Outer Ear:
The outer ear is called the pinna. This is the part of the ear that people can see. The main job of the outer ear is to collect sounds and also includes the ear canal, where wax is produced. Earwax contains chemicals that fight off infections that could hurt the skin inside the ear canal. It also collects dirt to help keep the ear canal clean.
The Middle Ear:
After sound waves enter the outer ear, they travel through the ear canal and make their way to the middle ear. The middle ear's main job is to take those sound waves and turn them into vibrations that are delivered to the inner ear. To do this, it needs the eardrum, which is a thin piece of skin stretched tight like a drum.
The eardrum separates the outer ear from the middle ear and the ossicles. What are ossicles? They are the three tiniest, most delicate bones in your body. They include:
•the malleus, which is attached to the eardrum and means "hammer" in Latin
•the incus, which is attached to the malleus and means "anvil" in Latin
•the stapes, the smallest bone in the body, which is attached to the incus and means "stirrup" in Latin
When sound waves reach the eardrum, they cause vibration. When the eardrum vibrates, it moves the tiny ossicles — from the hammer to the anvil and then to the stirrup. These bones help sound move along on its journey into the inner ear.
The Inner Ear:
Sound comes into the inner ear as vibrations and enters the cochlea, a small, curled tube in the inner ear. The cochlea is filled with liquid, which is set into motion, like a wave, when the ossicles vibrate. The cochlea is also lined with tiny cells covered in tiny hairs that are so small you would need a microscope to see them. They may be small, but they are extremely important. When sound reaches the cochlea, the vibrations (sound) cause the hairs on the cells to move, creating nerve signals that the brain understands as sound.
The brain puts it together and hooray! You can hear the sounds around you. It is extremely important to always ensure proper hearing healthcare. Whether it be protecting your vital sense from loud noise exposure to having regular hearing examinations. After all, hearing is what keeps us in touch with the world. For more information on proper hearing healthcare, visit your hearing health care professional today.