the human ear
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
The Human
EarDefinition: 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
• 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
Hammer
Anvil
StirrupEardrum
• These are the smallest bones in your body!
• Together, they’re about the size of an orange seed.
The Stirrup (or stapes)
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.
Cochlear Hair Cells in Action
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
Put the following steps in order:A. The stirrup moves back and forth,
creating pressure waves in the cochlea.
B. The bones of the middle ear (hammer, anvil, & stirrup) vibrate.
C. Hair cells send an electrical impulse through the auditory nerve.
D. The outer part of the ear (the pinna) "catches" the sound waves.
E. Sound waves vibrate the eardrumF. The brain receives an electrical
impulse and interprets it as sound. G. Tiny hair cells in the cochlea move
as the waves pass.H. The sound waves travel into the
ear canal.
DHEBAGCF