First, here are the parts of the ear:
- The outer ear
- The outer ear is made up of the ear flap and the ear canal up to the eardrum.
- The ear flap is also called the auricle or pinna.
- The ear drum is also called the tympanic membrane.
- The outer ear protects the middle and inner ears.
- The middle ear
- The middle ear is made up of three tiny bones and the Eustachian tube.
- The Eustachian tube connects the middle ear to the back of the throat. It opens and closes to make the pressure between the inner and outer ears the same.
- Three tiny bones connect the ear drum to the inner ear. The bones are called the hammer (malleus), anvil (incus) and stirrup (stapes).
- The inner ear
- The inner ear is made of the vestibular apparatus and the cochlea.
- The vestibular apparatus is three looping canals. They control your balance.
- The cochlea turns sound into electrical signals that get sent to the brain. The cochlea is spiral-shaped.
Now, here's how sounds get from the outside to our brains.
- Sound moves from the outside to your outer ear.
- The outer ear passes sound to the middle ear.
- Your middle ear passes sound to your inner ear.
- Sound makes your eardrum vibrate like a drum.
- The vibrations pass to the three tiny bones behind the eardrum. (These are the hammer, anvil and stirrup.)
- The bones pass the vibrations to the inner ear.
- The vibrations go to the cochlea in your inner ear.
- Tiny hair cells in the cochlea pick up the vibrations.
- The hair cells turn the vibrations into electrical signals.
- The electrical signals are sent to the auditory nerve, and then the brain.
- Your brain decides what the sound is.
- The auditory cortex is the part of the brain where the signals are put with other information. The other information could be what you see, and your memories.
- This helps us to "know" what we're hearing. (For example, you hear a car honk and think, "That's a car honking.")
