Whether for study, health, or just general trivia to impress at a dinner party, it’s pretty useful to know how the ears work and let us tell you, they’re a rather spectacular part of the body.
But let’s start with the basics
To understand how they work, we must first know what they do. Everyone knows our ears are responsible for transmitting sounds to our brain giving us the ability to hear, but some people are shocked to learn they actually supply another purpose, that is to keep us balanced.
In a nutshell, the jobs our ears are responsible for are these:
- Comprehending speech
- Identifying sounds that trigger good memories
- Recognizing sounds that alert us to danger
- Recognizing the diversity of life around us
- Keeping us upright and balanced
Right, OK, so how do they work?
- Firstly, sound is transmitted through the air as sound waves from the environment around us. The sound waves are gathered by the outer ear and sent down the ear canal to the eardrum.
- The sound waves cause the eardrum to vibrate, which sets the three tiny bones in the middle ear into motion.
- The motion of the three bones causes the fluid in the inner ear, or cochlea, to move.
- The movement of the fluid in the inner ear causes the hair cells in the cochlea to bend. The hair cells change the movement into electrical impulses.
- Finally, these electrical impulses are transmitted to the hearing (auditory) nerve and up to the brain, where they are interpreted as sound.
What are the different parts?
The ear is made up of 3 distinct parts, each serving a different purpose and each as important to our overall hearing quality as the next.
Part 1: The Outer Ear
The visible bit of the ear, this is called the “pinna” or “auricle.” Its main job is to collect sounds, give them a boost in volume, and ferry them through the canal, which is where the wax is produced and is critical for the canal’s protection guarding it against infection.
Part 2: The Middle Ear
Arguably the most precious and delicate part of the ear, the middle ear is where the magic happens. Once the sound waves go through the canal, they’re turned into vibrations that are then transported to the inner ear via the eardrum.
Although it’s extremely thin (hence why it’s very easy to burst), the eardrum is made up of 3 layers to increase its strength and separates the outer ear from the middle ear and 3 tiny bones called the ossicles.
These three bones form a connected chain in the middle ear. One of the bones is embedded in the innermost layer of the eardrum, and the third bone is connected to a membranous window of the inner ear. The ossicles take mechanical vibrations received at the tympanic membrane into the inner ear.
Did you know that when you swallow, yawn, or chew that it’s your middle ear’s air pressure equalizing system at work here?
It can also be intentionally opened to equalize pressure in the ears, such as when flying in an airplane. When this happens, you might hear a soft popping sound.
Now for part 3: The Inner Ear
The sound’s journey continues through the inner ear as vibrations and makes their way to the cochlea, a small twisty tube. 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 can only see them with a microscope. Although tiny, they’re incredibly crucial to our overall hearing ability. 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 voila!
Dr. Heidi J. Sorrells obtained her doctorate degree from Salus University in Elkins Park, Pennsylvania and master’s and bachelor’s degrees from Minot State University in Minot, North Dakota. She is a certified Audiologist by the American Speech-Language-Hearing Association (ASHA) and she holds a Louisiana and a Texas Audiology License. Dr. Sorrells enjoys all aspects of working in a private practice audiology clinic but especially loves the challenges of vestibular (balance) assessment and rehabilitation.