Download Hearing - OnCourse

Hearing
1
Focus
• How does the hearing process work?
2
Hearing
The Stimulus Input: Sound Waves
Sound waves are compressing and expanding air
molecules.
3
Sound Characteristics
1. Frequency (pitch)
2. Intensity (loudness)
3. Purity/quality
(timbre)
4
The Ear
Dr. Fred Hossler/ Visuals Unlimited
5
The Ear
Outer Ear: Collects and sends sounds to the
eardrum.
Middle Ear: Chamber between eardrum and
cochlea containing three tiny bones (hammer,
anvil, stirrup) that concentrate the vibrations
of the eardrum on the cochlea’s oval window.
Inner Ear: Innermost part of the ear,
containing the cochlea, semicircular canals,
and vestibular sacs.
6
Cochlea
Cochlea: Coiled, bony, fluid-filled tube in the
inner ear that transforms sound vibrations to
auditory signals.
7
Focus
• How can we tell where sound is coming
from?
• What processes within our bodies help
keep us balanced?
8
Intensity (Loudness)
Intensity
(Loudness):
Amount of energy
in a wave,
determined by the
amplitude, relates
to the perceived
loudness.
9
Loudness of Sound
Richard Kaylin/ Stone/ Getty Images
120dB
10
70dB
Frequency (Pitch)
Frequency (pitch):
The dimension of
frequency
determined by the
wavelength of
sound.
Wavelength: The
distance from the
peak of one wave
to the peak of the
next.
11
Localization of Sounds
Because we have two ears, sounds that reach
one ear faster than the other ear cause us to
localize the sound.
12
chapter 6
Auditory localization
Sounds from different
directions are not
identical as they arrive at
left and right ears.
Loudness
Timing
The brain calculates a
sound’s location by using
these differences.
Localization of Sound
1. Intensity differences
2. Time differences
Time differences as small as 1/100,000 of a second
can cause us to localize sound. The head acts as a
“shadow” or partial sound barrier.
14
Body Position and Movement
The sense of our body parts’ position and
movement is called kinesthesis or proprioception.
The vestibular sense monitors the head (and
body’s) position.
Bob Daemmrich/ The Image Works
http://www.heyokamagazine.com
Whirling Dervishes
Wire Walk
15
chapter 6
The environment within
Kinesthesis/Proprioception
The sense of body position and movement of body parts
Equilibrium
The sense of balance
Semicircular canals
Sense organs in the inner ear, which contribute to
equilibrium by responding to rotation of the head
Touch
Bruce Ayers/ Stone/ Getty Images
The sense of touch is a mix of four distinct skin
senses—pressure, warmth, cold, and pain.
17
Skin Senses
Only pressure has identifiable receptors. All other
skin sensations are variations of pressure, warmth,
cold and pain.
Pressure
Burning hot
Vibration
Vibration
Cold, warmth and pain
18
Touch
• Transduction = at nerve endings
• Different receptors = more sensitive to
different types of touch (mechanical,
thermal, chemical)
• Certain areas of body = more sensitive to
touch than others
– Lips, fingertips, face
19
The Man Who Lost His Body
(Proprioception)
http://www.youtube.com/watch?v=AvLRwRAAo
ww
Pain
Pain tells the body that something has gone wrong.
Usually pain results from damage to the skin and
other tissues. A rare disease exists in which the
afflicted person feels no pain.
AP Photo/ Stephen Morton
Ashley Blocker (right) feels neither pain
nor extreme hot or cold.
21
Painful Stimuli
Energy
Example
Everyday
Example
Possible result
if untreated
Mechanical
Strong Pressure Animal bite
Pinch
Knife cut
Squeeze
Falling off bike
Twist
Bruises
Broken Bones
Cuts
Thermal
(Temperature)
Hot
Cold
Fire
Hot chocolate
Ice
Burns
Frostbite
Electrical
Electric shock
Burns
Chemical
Acid
Chili peppers
Chemical burns
Broken skin
Visceral (inside
your body
Heart attack
Inflamed
appendix
Condition gets
worse
22
Biopsychosocial Influences
23
Gate-Control Theory
Melzack and Wall (1965, 1983) proposed that our
_______ ______contains neurological “gates” that
either block pain or allow it to be sensed.
Gary Comer/ PhototakeUSA.com
24
Gate-Control Theory
Melzack and Wall (1965, 1983) proposed that our
spinal cord contains neurological “gates” that
either block pain or allow it to be sensed.
Gary Comer/ PhototakeUSA.com
25
Pain Control
Pain can be controlled by a number of therapies
including, drugs, surgery, acupuncture, exercise,
hypnosis, and even thought distraction.
Todd Richards and Aric Vills, U.W.
©Hunter Hoffman, www.vrpain.com
26
Focus
1. What are the processes
involved in smell and taste
perception?
2. What is the role of sensory
interaction in our sensory
experiences?
27
Taste (Gustation)
Traditionally, taste sensations consisted of sweet,
salty, sour, and bitter tastes. Recently, receptors for
a fifth taste have been discovered called “Umami”.
Sweet
Sour
Salty
Bitter
Umami
(Fresh
Chicken)
28
Taste
•Transduction = in tastebuds
•located on tongue, on palate, in throat
• substances MUST BE DISSOLVED TO
BE TASTED
•tongue mapping for taste buds = inaccurate
• buds for different tastes = not just in one
area
• Smell, vision, touch (texture, temperature)
all influence taste
29
Sensory Interaction
When one sense affects another sense, sensory
interaction takes place. So, the taste of strawberry
interacts with its smell and its texture on the
tongue to produce flavor.
30
Smell (Olfaction)
Like taste, smell is a chemical sense. Odorants
enter the nasal cavity to stimulate 5 million
receptors to sense smell. Unlike taste, there are
many different forms of smell.
31
Smell
• Transduction = membrane in upper nasal
cavity
– Gases
– must be dissolved
– 500 different odor receptors
– can discriminate 10,000 different smells BUT
have trouble identifying what they are without
help from other senses
32
Smell
• Factors that influence odor perception
– Age
– Gender
– Disease/injury
– Adaptation
– Expectations (risks/health issues/color)
33
Smell
• Cultural issues
– What was considered to be a “good” odor
depended on the individual culture
– “Bad” odors were same across cultures
Bad odor #1 across all cultures?
“bathroom” odors
Bad odor #2 across all cultures?
rotting garbage
34
Smell and Memories
The brain region for
smell (in red) is closely
connected with the
brain regions involved
with memory (limbic
system). That is why
strong memories are
made through the sense
of smell.
35