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The Human Ear. Definition: the organ humans use to detect sound. http://www.a3bs.com/3d_models.html. The human ear is divided into three sections. Each part of the ear serves a specific purpose in the task of detecting and interpreting sound. The Outer Ear.
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The Human Ear Definition: the organ humans use to detect sound. http://www.a3bs.com/3d_models.html
Each part of the ear serves a specific purpose in the task of detecting and interpreting sound.
The Outer Ear • Picture a satellite dish that collects radio waves. • The outer ear is similar! • The curved formation on the outside ( the pinna) helps funnel sound down the ear canal to the eardrum.
The Middle Ear • The middle ear transfers the energy of a sound wave by vibrating the three bones found there.
Bones of the Middle Ear • These are the smallest bones in your body! • Together, they’re about the size of an orange seed. Hammer Anvil Eardrum Stirrup
How Sound Travels in the Middle Ear • When sound waves reach the middle ear, they cause the eardrum to vibrate. • This vibration then causes the three bones to vibrate. • These vibrations are transformed into longitudinal/pressure waves in the middle ear.
The Inner Ear • Two main parts: • Cochlea • Auditory Nerve
The Cochlea • Coiled like a snail shell • Contains approximately 300,000 hair cells • Is filled with fluid, through which sound can travel easily.
Cochlear Hair Cells • These tiny hairs bend because of the vibrations caused by the sound waves.
The Auditory Nerve • The tiny hair cells of the cochlea are set in motion by vibrations • The vibrations stimulate tiny nerve cells. • The nerve cells then send signals along the auditory nerve to the brain.
A sound is not actually heard until the brain receives and processes these signals.
Let’s start at the very beginning… • http://www.youtube.com/watch?v=CSO765hyxrc
D H E B A G C F Put the following steps in order: • The stirrup moves back and forth, creating pressure waves in the cochlea. • The bones of the middle ear (hammer, anvil, & stirrup) vibrate. • Hair cells send an electrical impulse through the auditory nerve. • The outer part of the ear (the pinna) "catches" the sound waves. • Sound waves vibrate the eardrum • The brain receives an electrical impulse and interprets it as sound. • Tiny hair cells in the cochlea move as the waves pass. • The sound waves travel into the ear canal.