Transcript The Human Ear - AP Psychology

The Human Ear
Auditory Sensation and Perception
Artificial Senses - Hearing
PINNA
• Also called the auricle.
The visible part of the
outer ear. It collects
sound and directs it into
the outer ear canal.
EXTERNAL AUDITORY
CANAL
•The tube through
which sound
travels to the
eardrum.
THE MIDDLE EAR
• The middle ear is a sealed, air filled
cavity which gives the eardrum the
ability to move easily, a property
called compliance. Compliance
means that the eardrum moves or
vibrates easily with little effort.
Compliance gives the eardrum the
ability to gather sound efficiently.
THE MIDDLE EAR
EARDRUM
•Also called the
tympanic membrane.
A thin membrane that
vibrates when sound
waves reach it.
HAMMER
•Also called the
malleus. A tiny bone
that passes vibrations
from the eardrum to
the anvil.
ANVIL
•Also called the incus.
A tiny bone that
passes vibrations from
the hammer to the
stirrup.
STIRRUP
• Also called the stapes. A tiny,
U-shaped bone that passes
vibrations from the stirrup to
the cochlea. This is the
smallest bone in the human
body (it is 0.25 to 0.33 cm
long).
EUSTACHIAN TUBE
• A tube that connects the middle ear to
the back of the nose; it equalizes the
pressure between the middle ear and
the air outside. When you "pop" your
ears as you change altitude (going up
a mountain or in an airplane), you are
equalizing the air pressure in your
middle ear.
THE EUSTACHIAN TUBE
• The eustachian tube is a selective valve that
allows air to enter behind the sealed
eardrum. The eustachian tube connects the
back of the nose to the middle ear. Air can
pass from the back of the nose to the middle
ear through the eustachian tube (see
diagram above). The eustachian tube
replaces the air the body absorbs from the
middle ear. The eustachian tube also
equalizes the pressure changes in the
outside air. This is what causes the
"popping" that people describe when going
up or down in the mountains or an airplane.
The ability to "pop" the ears is very
beneficial.
SEMICIRCLE CANALS
• Three loops of fluid-filled
tubes that are attached to
the cochlea in the inner ear.
They help us maintain our
sense of balance.
COCHLEA
• A spiral-shaped, fluid-filled
inner ear structure; it is lined
with cilia (tiny hairs) that
move when vibrated and
cause an electrical nerve
impulse to form.
VESTIBULAR COCHLEAR NERVE
•Carries electrochemical signals from
the inner ear (the
cochlea) to the brain.
HEARING/AUDITION
• The brain’s ability to receive sound waves
from the outside world
• Sound waves are the rhythmic vibrations
of air molecules
LOUDNESS
• The intensity/energy of a sound wave, measured
in decibels.
• On a graph, “amplitude” is the height of a sound
wave. The higher the wave, the more force it
will hit the eardrum with, and the resulting sound
is louder. The lower the wave, the less force it
will hit the eardrum with, and the resulting sound
is softer.
• Min = 0 decibels
Max = 120 decibels
PITCH
• Pitch is the property of sound that we
perceive as higher and lower tones.
Changes in pitch are caused by
differences in the frequency at which a
sound wave vibrates.
• On a graph, the more waves per second
results in a higher tone, and the less
waves per second results in a lower tone.
• Pitch is measured in Hertz (Hz) – how
many times a wave repeats per second
• Min = 20
Max = 20,000
TIMBRE
• The distinctive quality of
individual sounds.
• Created by an infinite
combination of high and low
frequencies (pitch), and high
and low amplitudes
(loudness).
Hearing:
Sound Localization
Localization of Sound
• Locating where sound is originating
from
• Done through two cues:
–Which ear hears the sound first?
–Which ear hears the louder sound?
Localization of Sound
Problems with hearing
• Conduction deafness
(middle ear damage)
• Nerve deafness (hair cell
or auditory nerve damage)