Download Hearing and the Ear - Ms. Brown Apex High School

Sensation:
Hearing and
Other Senses
A P P SYCH
MS . BROWN
M YE RS, CH. 5
Audition & the Ear
Audition – the sense/act of
hearing
We hear via sound waves
◦ Loudness – amplitude (height) of
wave
◦ Measured in decibels – dB
◦ Loud sounds have high amplitudes
◦ Softer sounds have smaller amplitudes
Audition – the sense/act of
hearing
◦ Pitch – a tone’s experienced highness or lowness,
depends on frequency
◦ Frequency – number of wavelengths that pass a point in a period of
time
◦ Low pitch/frequency sounds = bass
◦ High pitch/frequency sounds = high ringing
Outer Ear
Pinna – outer ear/lobe
External auditory canal –
channels sound waves to the
eardrum
Middle Ear – eardrum, 3
bones
Eardrum – thin membrane
that vibrates when a sound
waves hits it
◦ Vibrations felt by 3 small
ossicle bones – hammer,
anvil, and stirrup – and sent
to inner ear
Inner Ear - cochlea, semicircular
canals, and vestibular areas
Cochlea – a coiled, bony, fluidfilled tube in the inner ear
through which sound waves
trigger nerve impulses
◦ Moving fluid in cochlea  triggers
hair cells in the cochlea’s basilar
membrane stimulates neurons to
produce electrical impulses
Auditory nerve – sends neural
impulses from the cochlea to
the brain (thalamus  temporal
lobe)
Hearing Animation
Audition and Pitch Theories
Cochlea Animation
How Do We Hear Pitch?
PLACE THEORY (HELMHOLTZ)
Links the pitch we hear with the
place where the cochlea’s
membrane is stimulated
High pitch sounds
FREQUENCY THEORY
The rate of nerve impulses
traveling up the auditory nerve
matches the frequency of a tone,
thus enabling us to sense its pitch
Low pitch sounds
We use both theories to
hear all pitches.
Locating Sounds
Distance between ears allows us to place sounds in space.
Equidistant sounds – cock our heads to distinguish location
Hearing Loss
Conduction
◦ Damage to the mechanical elements
(eardrum, H, A, or S) that conduct sound
waves to the cochlea
Sensorineural
◦ Damage to the cochlea’s receptor cells or to
the auditory nerve, also called nerve
deafness
◦ Hearing can be slightly restored with a
cochlear implant (if there is a healthy nerve)
◦ Device for converting sounds into electrical signals and
stimulating the auditory nerve through electrodes
threaded into the cochlea.
◦ Must have a functioning auditory nerve
Cochlear Implants
Pro
Experience sounds and
oral communication
 Helps deaf children
with talking
 Children who rely
solely on ASL before
learning to speak have
more difficulty learning
to read and write later
in life

Con



Deafness is not a
disability
ASL is a complete
and functioning
language
Deafness ≠
linguistically
impaired
Sensory Compensation
People who lose one channel of sensation often compensate for
it with a slight enhancement of other sensory abilities
Also a product of brain plasticity
Other 3 Senses
OLFACTION, TASTE, TOUCH
Olfaction – sense of smell
Chemical sense - Odors are composed of
chemical molecules which are sensed by
olfactory receptor cells at the top of the
nasal cavity.
Receptors in nasal cavity (transduction)
 olfactory bulb  olfactory nerve 
primary smell cortex (temporal lobe)
◦ only sense not to pass through the
thalamus
Olfaction and
Memory/Emotion
Odors invoke memories or feelings because the part of the brain that
interprets odors is directly linked with the limbic system which
processes memories and emotions
Wrong
Gustation – Sense of Taste
Evolutionary purpose – survival
5 basic tastes
◦
◦
◦
◦
◦
Sweet
Salty
Sour
Bitter
Umami (best experienced by the flavor enhancer MSG, most commonly found in
Asian food – described as “savory”)
Gustation - Taste
Chemical sense – taste buds (200+ per
bump on tongue) catch food chemicals via
receptor cells
◦ Receptor cells can be more sensitive to
different tastes
Receptors on taste buds (transduction) 
facial nerve  meduala  thalamus 
primary gustatory region (temporal lobe)
Sensory Interaction
The principle that one sense may influence another, as when the smell
of food influences its taste
◦ To savor taste we normally breathe the aroma through the nose
◦ Sight of spoken words and the audition of spoken words influence each
other
Vision and audition
◦ We use the auditory info from the sound of words and the visual info from
the moving of the mouth to quickly comprehend speech.
◦ However, this sensory interaction can also lead us astray…
Flavor
Combination of odor, texture, temperature, and taste
◦ “taste blindness” – lack of sensitivity to certain taste
◦ Sensitivities can be inherited
Tea Flavors
Chocolate
Flavors
Touch - Skin Senses
3 distinct skin senses
◦
◦
◦
◦
Pressure
Temperature
Pain
These senses are combined to produce sensations such as: hot, tickling, itchy,
wetness, etc
Only the sensation of pressure has specialized nerves in the skin; the rest of
the nerve endings can feel warmth, cold, and pain in various combinations
Skin receptors (transduction)  nerves (PNS)  spinal cord (CNS) 
medulla  thalamus  sensory cortex
Pain: Gate-Control Theory
The spinal cord acts as a gate that controls if pain signals reach the
brain.
◦ Small nerve fibers conduct pain signals, while larger neural fibers conduct
most other sensory signals.
◦ When tissue is injured, the smaller nerve fibers activate and open the neural
gate to send pain to the brain.
◦ Larger-fiber activity closes the pain gate, turning pain off.
Using this theory, people believe that activating large neural fibers can
block pain
◦ Ex: acupuncture
◦ Ex: rubbing painful areas stimulates large neural fibers than can block pain
◦ Ex: electrical stimulation of painful area
Pain
Something is WRONG!
Biological
•Activity in spinal cord’s large and
small fibers (gate-control theory)
•Genetic differences in endorphin
production
•The brain’s interpretation of CNS
activity
Psychological
•Attention to pain
•Learning based on
experiences
•Expectations of pain
Perception
of Pain
Social Cultural
•Presence of others
•Empathy for other’s pain
•Cultural expectations
Pain Control
Pain can be treated physically and psychologically
◦ Drugs, surgery, acupuncture, electrical stimulation, massage, exercise,
hypnosis, relaxation training, thought distraction, etc
◦ Because pain is perceived in the brain, diverting the brain’s attention can
bring relief
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6
The and
Senses
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7
KINESTHESIS AND VESTIBULAR SENSE
Kinesthesis
AKA Proprioception
The system for sensing the position and
movement of individual body parts
◦ Enabled by millions of proprioceptors in muscles,
tendons, and joints
Proprioceptors (transduction)  nerves 
spinal cord  brain (cerebellum)
Vestibular Sense
The sense of body movement and position, including the sense of balance
◦ Monitors the head’s position which usually dictates what the body is doing
Fluid in semicircular canals  hair cells in vestibular sacs  vestibular nerve
 brain (medulla and cerebellum)
Crash Course - Sensation