Download Key Elements of Sensation

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Key Elements of Sensation
•
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Sensory Adaptation
• Loss of ____________________ to stimuli when receptor cells are
______________________ stimulated.
• _________________________ psychologists would argue that this was necessary for our
_____________ in order to focus attention on more important novel stimuli such as a
predator.
Sensory Transduction
• The ____________________________ of energy from environmental stimuli by
specialized receptor cells in sensory organs into _______________ messages.
• Receptor cells for each sense transduce or _______________ the incoming physical
stimuli into neural messages in the form of ______________ potentials traveling along
sensory (afferent) neurons to the brain for interpretation (perception).
TRANSDUCTION IN THE SENSES
Sense
Sense Organ
Stimuli
Photoreceptor cells:
_______ and
________ located in
the retina
Vision
________ (hair
cells) located on the
basilar membrane
of the ___________
Audition
(Hearing)
Gustation
(Taste)
Olfaction
(Smell)
Specialized
Receptor Cells
Molecules
dissolved in
_________ on
the __________
Taste receptor cells
in the
_____________
located in the
papillae
Molecules
dissolved in the
____________
membranes of
the nose
Olfactory receptor
cells that
communicate to the
olfactory _______
Pathway to the
Brain
__________________
↓
Thalamus
↓
Visual cortex in the
____________ lobes.
_________________
↓
Thalamus
↓
Auditory cortex in the
____________ lobes.
________________
↓
Thalamus
↓
__________ at the
junction of the
temporal and parietal
lobes
Olfactory Bulb
↓
______________ lobes
↓
__________ system
(does NOT travel
through the
thalamus!!)
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Sense
Somatic
(Touch)
Sense Organ
Stimuli
Specialized
Receptor Cells
Pressure on skin
based on
____________
of stimuli
Pressure receptor
cells located in the
__________
Temperature
___________ in
stimuli
Warm and cold
receptor cells
located in the skin
Temperature
Pain receptors
located in the
________
Pain
Vestibular
(Balance)
Kinesthetic
(Movement)
Changes in body
___________
and ________
________ (hair
cells) in the
semicircular
____________
Receptor cells
(proprioceptors)
located in joints,
tendons, and
muscles
Pathway to the
Brain
____________ or
___________ Nerves
↓
Thalamus
↓
Somatosensory cortex
at the front of the
_____________ lobes.
__________ Nerves
↓
Thalamus
↓
Somatosensory cortex
at the front of the
_____________ lobes.
* Temperature can
interact with touch
sensations.
Spinal Nerves
↓
Thalamus
↓
Somatosensory cortex
at the front of the
parietal lobes.
________________
Nerves
↓
Thalamus
↓
Several brain regions
including the
______________
Spinal Nerves
↓
Thalamus
↓
Somatosensory cortex
at the front of the
______________
lobes.
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How We See (The Process of Visual Sensation)
•
The entire process begins with a ________________ light wave that travels through the sense
organ of the eye and is ___________________ by specialized receptor cells to be transported to
the brain for ______________ perception.
Light Waves
1. Light waves from the visual spectrum for humans can be described in terms of three physical
properties and their equivalent psychological properties.
• Wavelength = hue
• Amplitude (intensity) = brightness
• Purity = saturation
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•
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Hue
•
Red has the ___________ wavelengths and violet has the
______________
Brightness
• Bright colors have ____________ waves (greater amplitude) and dull colors have
____________ waves (smaller amplitude)
Saturation (one wavelength vs. many)
• Colors that are ___________ saturated tend to be bright, intense, and vivid. Colors that
are _________ saturated are more pastel, pale, and soft.
Cataracts
Cataracts is the most common cause of vision loss in people over age 40 and is the principal cause of blindness in the world.
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Transduction
1. Light waves are __________ and ___________ by the cornea which protects the eye’s interior.
2. The focused light waves then travel through the ___________ controlled by the surrounding
_________ (the colored portion of the eye which is a ring of muscles that controls the ________
of the pupil allowing various degrees of light to enter the eye.
3. The _________ further bends the light waves and focuses them on the ___________ which is
located along the back of the eye. The lens is adjustable and changes shape, either flattening or
curving, in a process called _________________________.
4. __________ or ____________ at the back of the retina convert light waves into neural signals in
the process of transduction.
o
o
o
The nearly _____ million cones detect _________ and __________ and are most effective in
______________.
 There are three different types of cones that respond to long (red), medium (green), and
short (blue) wavelengths.
 Cones are mainly located in the ______________, a small central region of the retina
where visual acuity is the sharpest.
The nearly _______ million rods are primarily concentrated on the ________________________ or
periphery of the retina.
 Rods are very sensitive under ______________________ conditions but do not provide as
much acuity or detail and ________________ perceive color.
 When you notice an object in your peripheral vision, the object will appear as a shape
lacking detail because only rods along the outer edge of the retina were activated.
The processes by which rods and cones increase or decrease in sensitivity to light are called
_________ and _________ ________________ which is why entering or exiting a dark movie
theater on a bright sunny day will require a period of time before vision adjusts.
5. Bipolar cells _____________ neural signals from the rods and cones and ____________ the
messages to the ganglion cells.
6. Ganglion cells ___________ the neural signals, and their axons converge to form the optic nerve.
7. The optic nerve _____________ the neural messages through the thalamus to the primary visual
cortex located in the ______________ lobes.
o
o
There are no photoreceptors where the optic nerve leaves the eye (the optic disk). As a result, a
___________________, or gap within the field of vision, exists within each eye.
 However, individuals are ________________ of this blind spot because the brain fills in
the gap with information provided by the other eye or the surrounding visual field.
Part of the optic nerve from each eye crosses through the ______________________ to the
opposite hemisphere of the brain. Information from the right visual field (taken in by the left side
of each eye) will travel to the left hemisphere of the brain, and information from the left visual
field (taken in by the right side of each eye) will travel to the right hemisphere of the brain.
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How We Hear (The Process of Audition Sensation)
The sense of audition, or hearing, results from _______________________ created by vibrating objects
being converted into neural messages. Sound waves, like light waves, have three physical dimensions and
equivalent psychological properties.
 Frequency determines _____________ (highness or lowness of a sound)
o Measured in ___________ (Hz);
o Longer wavelengths or low frequencies create lower pitched sounds.
o Shorter wavelengths or high frequencies create higher pitched sounds.
 Amplitude (intensity) determines ________________
o Measured in _____________ (dB)
o Higher amplitude or tall waves create louder sounds.
o Lower amplitudes or short waves create softer sounds.
 Purity determines ______________
o Pure tones are possible in lab experiments but difficult in the natural world
1. Sounds waves first enter the
outer visible portion of the
ear, called the __________,
and then move down the
auditory canal (ear canal) to
the ________________
membrane (eardrum) that
______________ in response
to the funneled sound waves.
2. The middle ear (between the
tympanic membrane and the
cochlea) contains the
_____________ (the three
smallest bones in the body)
which help ____________
sound waves traveling to the
inner ear.
3. The inner ear contains two
sense organs: the
___________ concerned with
hearing and the
_____________________
concerned with balance.
 The cochlea is a ________-filled and coiled tube where sound waves are
_________________ into neural impulses.
 Covering the opening to the inner ear is a membrane called the ___________________.
Pressure here causes waves in the fluid to move to the ______________ membrane. The
sound waves cause the ___________ (hair cells) to bend, initiating the process of
transduction.
4. The signals travel along the auditory nerve through the thalamus to the __________________
lobe’s auditory cortex.
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Hearing Theories
 Frequency Theory
o According to the frequency theory, the _________________ membrane vibrates at the
same frequency as the ______________________.
o The frequency theory explains how ______-frequency sounds are transmitted to the
brain.
o However, since individual neurons cannot fire faster than about ___________ times per
second, the frequency theory does not explain how the much faster high-frequency
sounds are transmitted.
 The volley theory suggests that sounds above 1,000 hertz require the activity of
________________ neurons working together.
 Place Theory
o According to the place theory, different _________________ excite different
_________________ at different ________________ along the basilar membrane.
o High-frequency sounds cause maximum vibrations near the ___________ end of the
basilar membrane. Lower-frequency sounds cause maximum vibrations at the
_______________ end.
Sound Localization
 Involves interpretation by the brain of sound waves entering ____________ ears in order to
determine the __________________ the noise is coming from.
 Possible because the sound waves arrive at one ear faster than they reach the other ear, and this
information about ______________ is then interpreted by the brain.
 Sounds that originate directly ____________, ____________, in ___________ of, or ___________
a person are the most difficult to locate because they reach each ear at the ___________ time
and with the same intensity.
o In order to determine the location of these sounds, humans also utilize their sense of
_____________ or move their heads to cause the messages to arrive at different times.
Deafness
 Conduction Deafness
o The result of problems with _________________ and _______________ sound waves to
the inner ear
o Typically the result of damage to the ______________ or the bones of the middle ear
o A person will have ___________ difficulty hearing both high- and low- pitched sounds
(sounds have become softer).
o Treatments include medication, surgery, or the use of a hearing aid to amplify the sound
waves to the cochlea
 Sensorineural (nerve) Deafness
o The result of damage to the aspects of the auditory system related to the
______________________ of sound waves, or the transmission or neural messages.
o Typically the result of damage to the __________ caused by prolonged _______________
to loud noise, ___________, or _________________.
o Hair cells (cilia) do not regenerate so the damage is ________________________.
o A person will have a much harder time hearing ____________-pitched sounds than low
ones.
o Treatment is most likely hearing aids but severe damage can be treated with cochlear
____________________.
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How We Taste (The Process of Gustation Sensation)
The chemical senses of __________ and __________ respond to chemical molecules dissolved in
____________ (taste) or that are found in the ______ (smell). The chemical senses serve two purposes:
(1) identification of molecules safe to _______________ and (2) identification and ______________ of
molecules that are dangerous.
Transduction for the chemical sense of gustation occurs when molecules mix with ___________. Taste
receptor cells are mostly located within taste buds and are NOT _____________ to the human eye. Taste
buds are clustered in small bumps, known as _________________ that are along the surface of the
tongue. There are also receptors for taste at the back of the throat and along the roof of the mouth.
Five Basic Tastes:
1. ____________
2. ____________
3. ____________
4. ____________
5. ____________ (most recent discovery; a flavor enhancer associate with glutamate; meaty or savory)
Considerable _______________ exists between individuals in terms of how ________________ they are
to various tastes, and this sensitivity is mostly determined by _________________.
• Both humans and other animals prefer ___________ and ________ tastes to sour and bitter ones.
• Evolutionary psychologists believe that these preferences evolved to help humans and animal
more easily identify _______________ foods and avoid that that are ____________ or poisonous.
• Taste receptors _____________________ every 1-2 weeks but overall responsiveness to taste
_________________ with age and activities such as smoking and drinking alcohol.
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How We Smell (The Process of Olfaction Sensation)
Our sense of smell results from chemicals in the air (_______________) entering the nostrils and
sweeping upward to dissolve in _________________ membranes containing olfactory receptor cells. The
specialized receptor cells for olfaction are hair cells, or _________.
Researchers have been _______________ to identify specific basic smells, as they have for taste. It
appears there are at least ________ different types of olfactory receptor cells that allow for the
detections of over 10,000 different odors.
The axons of the olfactory receptors
travel to the
______________________________,
located below the frontal lobe.
Unlike all the other sense, olfaction
does _______ involve processing by
the thalamus, but instead travels
directly to the olfactory areas of the
___________________ lobe that
pass the information to the
________________ system.
Contact with the limbic system
structures, including the
hippocampus and
amygdala, create the
strong
_________________
responses and
_______________
associated with smell.
Sensory Phenomena
Sensory Interaction
• Involves one sense ________________ another.
o The perception of _____________ as the combination of smell and taste as well
as temperature and texture
Synthesia
• Stimulation of one sensory system generates _________________ sensations in another
sensory system. Research shows ≈ 1 in 2,000 have regular experiences, and 1 in 300 have
some
• Being able to ____________ colors and ____________ shapes
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How We Touch (The Process of Somatic Sensation)
Transduction for the sensation of touch occurs when specialized receptor cells located in the __________
throughout the body respond to physical pressure, temperature, or chemicals.
The sense of touch is perceived in the brain
by _________________________________
(sensations on the left side are perceived
by the somatosensory cortex in the right
hemisphere and vice versa). Additionally,
areas of the body that are more sensitive to
touch are represented by greater
____________________________ along
the somatosensory cortex.
PAIN
Although pain is an unpleasant
experience, it is ____________ for
survival because it generates a rapid
_______________ designed to reduce
or prevent damage from occurring to
tissues.
There are pain receptors located
throughout the body which follow one
of two main pathways to the brain.
1. Fast Pathway or A-delta fibers (__________________ nerves that carry ________/acute pain
messages)
2. Slow Pathway or C-fibers (_____________________ nerves that carry ___________ pain
messages that persist after the initial injury; the throbbing sensation of chronic pain)
Gate-Control Theory (Melzack and Wall)
• An explanation for how the perception of pain can be _____________________ and controlled.
• Based on the idea that pain signals traveling to the brain via the spinal cord pass through a series
of _____________________ doors or gates.
o These gates open to allow pain signals to travel to the brain or close to block pain signals.
 (1) To close the gates, additional sensory information traveling _____ the spinal
cord ________________ the passage of pain messages (like when you run the
area around the injury and the rubbing sensation reduces the transmission or
pain signals.
 (2) To close the gates, the brain may send signals ___________ the spinal cord,
closing the gate and preventing additional pain messages from traveling to the
brain. This can include distractions, emotions, visual input, and the release of
______________________ all of which can impact how much or how little pain is
perceived.