introduction to psychology, 7th edition, rod plotnik module 5: sensation module 5 sensation
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Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
Module 5
Sensation
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EYE: VISION
• Structure and function– eyes perform two separate processes– first: gather and focus light into precise area in the
back of eye– second: area absorbs and transforms light waves
into electrical impulses– process called transduction
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
p95 EYE
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EYE: VISION
• Structure and function– Vision: 7 steps
• Image reversed• Light waves• Cornea• Pupil• Iris• Lens• Retina
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EYE: VISION
• Structure and function– Image reversed
• In the back of the eye, objects appear upside down.
• somehow the brain turns the objects right side up
– Light waves• light waves are changed from broad beams to
narrow, focused ones
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
• Structure and function– Cornea
• rounded, transparent covering over the front of your eye
– Pupil• round opening at the front of the eye that allows
light waves to pass into the eye’s interior
EYE: VISION
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EYE: VISION
• Structure and function– Iris
• circular muscle that surrounds the pupil and controls the amount of light entering the eye
– Lens• transparent, oval structure whose curved
surface bends and focuses light waves into an even narrower beam
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EYE: VISION
• Structure and function– Retina
• located at the very back of the eyeball, is a thin film that contains cells that are extremely sensitive to light
• light sensitive cells, called photoreceptors, begin the process of transduction by absorbing light waves
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
p96 RETINA
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EYE: VISION
• Visual pathways: Eye to brain– Optic nerve– Primary visual cortex– Visual association areas
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
p97 VISUAL SYSTEM
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EYE: VISION
• Visual pathways: eye to brain– Optic nerve
• nerve impulses flow through the optic nerve as it exits from the back of the eye
• the exit point is the “blind spot”• the optic nerves partially cross and pass
through the thalamus• the thalamus relays impulses to the back of the
occipital lobe in the right and left hemisphere
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
• Visual pathways: eye to brain– Primary visual cortex
• the backs of the occipitals lobes is where primary visual cortex transforms nerve impulses into simple visual sensations
– Visual association areas• the primary visual cortex sends simple visual
sensations to neighboring association areas
EYE: VISION
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EAR: AUDITION• Stimulus:
– Sound waves• stimuli for hearing (audition)• ripples of different sizes• Sound waves travel through space with varying
heights and frequency.– Height
• distance from the bottom to the top of a sound wave
• called amplitude– Frequency
• number of sound waves occurring within one second
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EAR: AUDITION
• Measuring sound waves– decibel: unit to measure loudness– threshold for hearing:
• 0 decibels (no sound)• 140 decibels (pain and permanent hearing loss
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
p101 DECIBEL CHART
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EAR: AUDITION
• Outer, middle, and inner ear– Outer ear
• consists of three structures• external ear• auditory canal• tympanic membrane
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
• Outer, middle, and inner ear– Outer ear
• external ear– oval shaped structure that protrudes from
the side of the head• function
– pick up sound waves and then send them down the auditory canal
EAR: AUDITION
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EAR: AUDITION
• Outer, middle, and inner ear– Outer ear
• auditory canal– long tube that funnels sound waves down its
length so that the waves strike the tympanic membrane (ear drum)
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EAR: AUDITION
• Outer, middle, and inner ear– Outer ear
• tympanic membrane– taut, thin structure commonly called the
eardrum– Sound waves strike the tympanic
membrane and cause it to vibrate
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
p102 EAR DIAGRAM
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EAR: AUDITION
• Outer, middle, and inner ear– Middle ear
• bony cavity sealed at each end by membranes.
• the membranes are connected by three tiny bones called ossicles
• hammer, anvil and stirrup– hammer is attached to the back of the
tympanic membrane– anvil receives vibrations from the hammer– stirrup makes the connection to the oval
window (end membrane)
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EAR: AUDITION
• Outer, middle, and inner ear– Inner ear
• contains two structures sealed by bone– cochlea: involved in hearing– vestibular system: involved in balance
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
EAR: AUDITION
• Cochlea– bony coiled exterior that resembles a snail’s shell– contains receptors for hearing– function is transduction– transforms vibrations into nerve impulses that are
sent to the brain for processing into auditory information
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
• Auditory brain areas– sensations and perceptions– two step process occurs after the nerve impulses
reach the brain– primary auditory cortex– top edge of temporal lobe– transforms nerve impulses into basic auditory
sensations– auditory association area – combines meaningless auditory sensations into
perceptions, which are meaningful melodies, songs, words, or sentences
EAR: AUDITION
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
VESTIBULAR SYSTEM: BALANCE
• Position and balance– vestibular system is located above the cochlea in
the inner ear– includes semicircular canals– bony arches set at different angles– each semicircular canal is filled with fluid that
moves in response to movements of your head– canals have hair cells that respond to the fluid
movement– function of vestibular system– include sensing the position of the head, keeping
the head upright, and maintaining balance
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
CHEMICAL SENSES
• Taste– chemical sense because the stimuli are various
chemicals– tongue– surface of the tongue– taste buds
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
CHEMICAL SENSES (CONT.)
• Tongue– Five basic tastes
• sweet• salty• sour• bitter• umami: meaty-cheesy taste
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
CHEMICAL SENSES (CONT.)
• Surface of the tongue– chemicals, which are the stimuli for taste, break
down into molecules – molecules mix with saliva an run into narrow
trenches on the surface of the tongue– molecules then stimulate the taste buds
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
CHEMICAL SENSES (CONT.)
• Taste buds– shaped like miniature onions– receptors for taste– chemicals dissolved in saliva activate taste buds– produce nerve impulses that reach areas of the
brain’s parietal lobe– brain transforms impulses into sensations of taste
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
CHEMICAL SENSES (CONT.)
• Smell, or olfaction– Olfaction
• called a chemical sense because its stimuli are various chemicals that are carried by the air
• Function of olfaction– receptors, through transduction, transform
chemical reactions into nerve impulses
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
p107 OLFACTORY BULB
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
CHEMICAL SENSES (CONT.)
• Smell, or olfaction– Steps for olfaction
• Stimulus• Olfactory cells• Sensation and memories• Functions of olfaction
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
CHEMICAL SENSES (CONT.)
• Smell, or olfaction– Stimulus
• we smell volatile substances• volatile substances are released molecules in
the the air at room temperature• example:
– skunk spray, perfumes, warm brownies; not glass or steel
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
CHEMICAL SENSES (CONT.)
• Smell, or olfaction– Olfactory cells
• receptors for smell are located in a I-inch-square patches of tissue in the uppermost part of the nasal passages.
• olfactory cells are covered in mucus• which volatile molecules dissolve and stimulate
the cells• the cells trigger nerve impulses that travel to
the brain• which interprets the impulses as different
smells
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
CHEMICAL SENSES (CONT.)
• Smell, or olfaction– Sensations and memories
• nerve impulses travel to the olfactory bulb• impulses are relayed to the primary olfactory
cortex• cortex transforms nerve impulses into olfactory
sensations• Can identify as many as 10,000 different odors• we stop smelling our deodorants or perfumes
because of decreased responding• called adaptation
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
CHEMICAL SENSES (CONT.)
• Smell, or olfaction– Functions of olfaction
• one function: to intensify the taste of food• second function: to warn of potentially
dangerous foods• third function: elicit strong memories; emotional
feelings
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
TOUCH
• Touch– includes pressure, temperature, and pain
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
p108 SKIN
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
TOUCH (CONT.)
• Receptors in the skin– skin– hair receptors– free nerve endings– Pacinian corpuscle
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
TOUCH (CONT.)
• Skin– outermost layer– thin film of dead cells containing no receptors– just below, are fist receptors which look like
groups of threadlike extensions– middle and fatty layer– variety of receptors with different shapes and
functions– some are hair receptors
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
TOUCH (CONT.)
• Hair receptors– free nerve endings wrapped around the base of
each hair follicle– hair follicles fire with a burst of activity when first
bent– If hair remains bent for a period of time, the
receptors will cease firing.– sensory adaptation– example: wearing a watch
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
TOUCH (CONT.)
• Free nerve endings– near bottom of the outer layer of skin – have nothing protecting or surrounding them
• Pacinian corpuscle– in fatty layer of skin– largest touch sensor– highly sensitive to touch– responds to vibration and adapts very quickly
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
TOUCH (CONT.)
• Brain areas– somatosensory cortex– located in the parietal lobe– transforms nerve impulses into sensations of
touch temperature, and pain
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
PAIN
• What causes pain?– pain: unpleasant sensory and emotional
experience that may result from tissue damage, one’s thoughts or beliefs, or environmental stressors
– pain results from many different stimuli
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
p112 BRAIN PAIN
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
PAIN (CONT.)
• How does the mind stop pain?– gate control theory of pain– nonpainful nerve impulses compete with pain
impulses in trying to reach the brain– creates a bottleneck or neutral gate– shifting attention or rubbing an injured area
decreases the passage of painful impulses– result: pain is dulled
Introduction to Psychology, 7th Edition, Rod PlotnikModule 5: Sensation
PAIN (CONT.)
• Endorphins– chemicals produced by the brain and secreted in
response to injury or severe physical or psychological stress
– pain reducing properties of endorphins are similar to those of morphine
– brain produces endorphins in situations that evoke great fear, anxiety, stress or bodily injury as well as intense aerobic activity