The Ear

Parts of the Ear

The ear acts as a pathway for sound to reach the brain. It has three main sections: the outer ear, the middle ear, and the inner ear. Each section has its own parts, and every part plays a special role in how sound travels to the brain. In simple terms, the outer ear collects sounds, the middle ear sends the sounds along, and the inner ear turns sound into signals our brain can understand.  

Outer Ear

• Pinna – the part of the ear you can see
• Ear canal – narrow passageway where sound first enters the ear

Middle Ear

• Eardrum – vibrates from sound waves and starts a chain reaction of sending messages through the ear
• Ossicular Chain – three bones (the malleus, incus, and stapes) that increase the sound vibrations and send them to the cochlea
• Eustachian tube – a narrow tube connecting the middle ear to the back of the throat

Inner Ear

• Cochlea – a snail-shaped tube filled with fluid and lined with hair cells that sense the different tones of sound; hair cells convert sound into electrical signals
• Auditory Nerve – carries the electrical signals from the cochlea to the brain
• Semicircular canals – part of your vestibular system; the canals are filled with fluid and help regulate your balance
• Vestibular Nerve – sends information to the brain for balance and spatial orientation

The Journey of Sound to the Brain

1. Sound enters the ear through the ear canal.
2. It reaches the middle ear and the eardrum vibrates.
3. The bones in the middle ear move and increase the sound vibrations.
4. The sound vibrations move the fluid inside the cochlea within the inner ear.
5. The hair cells inside the cochlea vibrate and are turned into electrical signals.
6. The electrical signals are carried to the brain by the auditory nerve.
7. The brain processes the message sent.

Video: Journey of Sound to the Brain