Module 5 Sensation

THREE DEFINITONS Eyes, ears, nose, skin, and tongue are complex, miniaturized, living sense organs that automatically gather information about your environment Transduction Process in which a sense organ changes, or transforms, _____________into electrical signals that become _________, which may be sent to the brain for processing Adaptation The ___________ response of the sense organs as they’re exposed to a continuous level of stimulation

THREE DEFINITONS (CONT’D) Sensation versus perception Relatively ___________ bits of information that result when the brain processes electrical signals that come from the sense organs Perceptions _____________ sensory experiences that result after the brain combines hundreds of sensations

EYE: VISION (CONT’D) Stimulus: light waves Invisible (too short) ________________________________ Visible (just right) particular segment of electromagnetic energy that we can see because these waves are the right length to stimulate _________________ in the eye Invisible (too long) _______________________________

EYE: VISION (CONT’D) Structure and function Eyes perform two separate processes First:____________________________________________________________________________________________________________________ second: _______________________________________ _____________________________________________________________________________________________ Process called transduction

EYE: VISION (CONT’D) Structure and function Vision: seven steps ________________________________ _________________________________ __________________________________ ___________________________________ ___________________________

EYE: VISION (CONT’D) 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

EYE: VISION (CONT’D) Structure and function Cornea ________________________________________________________________________________ Pupil

EYE: VISION (CONT’D) Structure and function Iris ________________________________________________________________________________________________________________________ Lens

EYE: VISION (CONT’D) Structure and function Retina ________________________________________________________________________________________________________________________

EYE: VISION (CONT’D) Retina Three layers of cells __________________________________________________________________________________________________________________________________________ ______________________________________________ ____________________________________________________________________________________________

EYE: VISION (CONT’D) Rods Photoreceptor that contain a single chemical, called ___________________________ ________________________________________________ _______________________________

EYE: VISION (CONT’D) Cones Photoreceptors that contain three chemicals called _______ _______________________________ _____________________________________ ___________________________________________ ____________________________________________

EYE: VISION (CONT’D) Visual pathways: eye to brain ____________________________________ _____________________________________ __________________________________________

EYE: VISION (CONT’D) Visual pathways: eye to brain Optic nerve _______________________________________________________________________________ _____________________________________ ____________________________________________________________________________________________

EYE: VISION (CONT’D) Visual pathways: eye to brain Primary visual cortex back of the occipital lobes is where primary visual cortex transforms nerve impulses into simple visual sensations Visual association areas primary visual cortex sends simple visual sensations to neighboring association areas damage to the visual association area = visual agnosia: difficulty in assembling simple visual sensations into more complex, meaningful images

EYE: VISION (CONT’D) Making colors from wavelengths Sunlight is called white light because it contains all the light waves White light passes through a prism; separates light waves that vary in length Visual system transforms light waves of various lengths into millions of different colors Shorter wavelengths of violet, blue, green Longer wavelengths of yellow, orange, and red An apple is seen as red because reflection of longer light waves that brain interprets as red

EYE: VISION (CONT’D) Color vision Trichromatic theory three different kinds of _________ in the ________ each cone contains one of the three different light-sensitive chemicals, called ____________ each of the three _________ is most responsive to wavelengths that correspond to each of the three primary colors _________, __________, ___________ all colors can be mixed from these primary colors

EYE: VISION (CONT’D) Opponent-process theory Afterimage ____________________________________________________________________________________________ when excited, ______________________________ when inhibited, _________________________________

EYE: VISION (CONT’D) Color blindness Inability to distinguish two or more shades in the color spectrum Monochromatic _______________________________________ Dichromatic __________________________________ ______________________________________ ________________________________________

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; amplitude Frequency number of sound waves occurring within a second

EAR: AUDITION (CONT’D) Loudness Subjective experience of a sound’s intensity Brain calculates loudness from specific physical energy (amplitude of sound waves) Pitch Subjective experience of a sound being high or low Brain calculates from specific physical stimuli Speed or frequency of sound waves Measured in cycles (how many sound waves in a second)

EAR: AUDITION (CONT’D) Measuring sound waves Decibel: _________________________________ Threshold for hearing 0 decibels (no sound) 140 decibels (pain and permanent hearing loss)

EAR: AUDITION (CONT’D) Outer, middle, and inner ear Outer ear consists of three structures __________________________________

EAR: AUDITION (CONT’D) Outer, middle, and inner ear Outer ear external ear ______________________________________ _______________________________________ Function ___________________________________________ ____________________________________________

EAR: AUDITION (CONT’D) Outer, middle, and inner ear Outer ear auditory canal ______________________________________ _____________________________________________________________________________

EAR: AUDITION (CONT’D) Outer, middle, and inner ear Outer ear tympanic membrane _____________________________________ _______________________________________ ______________________________________ _________________________________________________________________________

EAR: AUDITION (CONT’D) Outer, middle, and inner ear Middle ear bony cavity sealed at each end by membranes that are connected by three tiny bones called ossicles hammer, anvil, and stirrup hammer is attached to the back of the tympanic membrane anvil ______________________from the hammer stirrup ___________________________________(end membrane)

EAR: AUDITION (CONT’D) Outer, middle, and inner ear Inner ear contains two structures sealed by bone cochlea: _____________________________ vestibular system: ______________________

EAR: AUDITION (CONT’D) Cochlea Bony coiled exterior that resembles a snail’s shell Contains _______________________________ Function is _______________________________ Transforms vibrations into nerve impulses sent to the ____________ for processing into auditory information

EAR: AUDITION (CONT’D)

EAR: AUDITION (CONT’D) 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_________________ __________________________________________ Auditory association area Combines meaningless auditory sensations _____________ __________________________________________________

EAR: AUDITION (CONT’D) Auditory cues Direction of sound determined by brain; calculates slight difference in time it takes sound waves to reach the two ears Calculating pitch frequency theory applies only to low-pitched sounds Rate that nerve impulses reach the brain determines how low a sound’s pitch is place theory brain determines medium-to-higher-pitched sounds from the place on the basilar membrane where maximum vibration occurs

EAR: AUDITION (CONT’D) Auditory cues Calculating loudness brain calculates loudness primarily from the frequency or rate of how fast or how slow nerve impulses arrive from the auditory nerve

VESTIBULAR SYSTEM: BALANCE Position and balance Vestibular system is located above the cochlea in the inner ear Includes ______________________________ Bony arches set at different angles Each semicircular canal is filled with ________ that moves in response to movements of your head Canals have hair cells that respond to the fluid movement Function of vestibular system ________________________________________________ __________________________________________________________________________________________________

VESTIBULAR SYSTEM: BALANCE (CONT’D) Motion sickness (sensory mismatch between information from the vestibular system) symptoms: feelings of discomfort, nausea, and dizziness in a moving vehicle head bouncing, but distant objects look fairly steady Meniere’s disease (malfunction of the semicircular canals of the vestibular system) symptoms: dizziness, nausea, vomiting, spinning, and piercing buzzing sounds Vertigo (malfunction of the semicircular canals of the vestibular system) symptoms: dizziness and nausea

CHEMICAL SENSES Taste Chemical sense because the stimuli are various _______________________________________ Tongue Surface of the tongue Taste buds

CHEMICAL SENSES (CONT’D) Tongue Five basic tastes ______________________ _____________________________

CHEMICAL SENSES (CONT’D) Surface of the tongue Chemicals, which are the stimuli for taste, break down into molecules Molecules mix with saliva and run into narrow trenches on the surface of the tongue Molecules then stimulate the taste buds

CHEMICAL SENSES (CONT’D) Taste buds _________________________________ __________________________________________ Produce nerve impulses that reach areas of the brain’s parietal lobe Flavor _________________________________________

CHEMICAL SENSES (CONT’D)

CHEMICAL SENSES (CONT’D) Smell, or olfaction Steps for olfaction _____________________________________ ______________________________________ ________________________________________

CHEMICAL SENSES (CONT’D) Smell, or olfaction Stimulus ________________________________________ __________________________________________ ________________________________________________________________________________________________________________________

CHEMICAL SENSES (CONT’D) Smell, or olfaction Olfactory cells receptors for smell located in a one-inch-square patch of tissue in the uppermost part of the nasal passages olfactory cells are covered in mucus that dissolves volatile molecules and stimulates the cells the cells trigger nerve impulses that travel to the brain, which interprets the impulses as different smells

Smell, or olfaction Sensations and memories ________________________________________ ___________________________________________________________________________ __________________________________________________________________ we can identify as many as ___________ different odors __________________________________________________________________________________________________________________________________________

CHEMICAL SENSES (CONT’D) Smell, or olfaction Functions of olfaction one function: ______________________________ second function: ________________________________________________________________________________ third function: ________________________________________________________________________________________________________________________

CHEMICAL SENSES (CONT’D)

TOUCH Touch Includes ___________________________________ Beneath the outer layer of skin are a half-dozen miniature sensors that are receptors for the sense of touch _________________________________________________________________________________________________________________________________

TOUCH (CONT’D) Receptors in the skin ____________________________

TOUCH (CONT’D) Skin Outermost layer Thin film of dead cells containing no receptors Just below are first receptors, which look like groups of thread-like extensions Middle and fatty layer Variety of receptors with different shapes and functions Some are hair receptors

TOUCH (CONT’D) 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

TOUCH (CONT’D) 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

TOUCH (CONT’D) Brain areas __________________________________________ _______________________________________________________________________________________

PAIN What causes pain? Pain: _________________________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________________________

PAIN (CONT’D)

PAIN (CONT’D) 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

PAIN (CONT’D) 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

PAIN (CONT’D) Dread Connected to pain centers in brain Not the act itself that people fear Time waiting before event causes dread Acupuncture Trained practitioners insert thin needles into various points on the body’s surface and then manually twirl or electrically stimulate the needles After 10 to 20 minutes of stimulation, patients often report a reduction in various kinds of pain