Download Chapter 16.4 How you hear sound

Chapter 16.4 How You Hear
Sound
Pg. 558- 560
The Human Ear
• The function of the ear is
to gather sound waves and
send or transmit,
information about sound
to your brain
• Your ear has three main
sections:
1.
2.
3.
The Outer Ear
The Middle Ear
The Inner Ear
• Each section has its own
unique function
The Outer Ear
• The outer ear looks and
functions like a funnel
• The main function of the
outer ear is to funnel sound
waves
• The components of the outer
ear are the ear canal and
eardrum
The Outer Ear
• The outer ear collects
sound waves and directs
them into a narrow region
called the ear canal
– The ear canal is a few
centimeters long and ends
at the eardrum
• The eardrum is a small
tightly stretched, drumlike
membrane
– Sound waves make your
eardrum vibrate
The Middle Ear
• The middle ear is located behind the eardrum
• The middle ear contains the three smallest bones
in your body
– The hammer
• The hammer is attached to the eardrum and vibrates when
the eardrum vibrates
• The hammer transmits vibrations to the anvil first and the
stirrups second
– The anvil
– The stirrup
Inner Ear
• The inner ear is separated from the middle ear by a
membrane
– When the stirrup vibrates it vibrates against the
membrane and the vibrations pass into the cochlea
• The Cochlea is a fluid-filled cavity shaped like a snail
shell
– The cochlea contains more than 10,000 tiny structures
called hair cells
The Inner Ear
• The tiny hair cells have
hairlike projections that float
in the fluid of the cochlea
– When vibrations move through
the fluid the hair cells move,
causing messages to be sent to
the brain via the auditory nerve
– The brain processes the
messages and tells you what
you’ve heard
Hearing Loss
• When hearing loss occurs a person may have
difficulty hearing soft sounds or high-pitched
sounds
• There are many different causes of hearing
loss such as, injury, infection, exposure to loud
sounds, and aging
Causes of Hearing Loss
• Injury: Hearing loss can occur when the
eardrum is damaged or punctured.
– This is why it is dangerous to stick objects in your
ears
• Infection: Can cause damage to the delicate
inner ear and cause permanent hearing loss
Causes of Hearing Loss
• Extended exposure to loud sounds can damage
hair cells in the ear
– The damaged hair cells will no longer be able to
send signals to the brain
– This type of damage can be prevented!
• Aging: This is the most common form of hearing
loss and it occurs gradually
– As people get older their hair cells in the cochlea
begin to die ( AND THEY CANNOT BE REPLACED)
– People with this kind of hearing loss often have
difficulty hearing high-frequency sounds
Hearing Aids
• For certain types of hearing loss, hearing aids
can restore some ability to hear
– Hearing aids amplify sounds entering the ear, and
others can amplify specific frequencies that they
person has lost the ability to hear
– Hearing aids come in all different sizes
Partner Project
• Ask Your Partner what sound they hear
throughout the day
– List at least 15 sounds your partner hears
– Ask them to rank the sounds they hear ask either
painful, quiet, normal, loud
– Then ask them to rate each sound as pleasant,
neutral, or annoying
– Also for each sound record the source, location,
time of day, and time exposed to the sound
– How are the sound ratings similar? How are they
different?
Sound
Source
Location
Time of
day
Time of
exposure
Painful,
quiet,
normal,
loud?
Annoying,
pleasant,
neutral?