Chapter 4.2 Flashcards
Light
-a form of electromagnetic radiation that travels as a wave
Amplitude
-affects the perception of brightness
Wavelength
-affects the perception of colour (hue)
Purity
-influences perception of the saturation/richness of colour
Additive Colour Mixing
-mixing the red, green, blue hues to produce any colour
-white light produced from mixing equal amounts of red, green, blue
Subtractive Colour Mixing
-mixing pigmented like paint or ink
Colour
-wavelengths of light are reflected and the wavelengths create a pattern of firing in photoreceptors
-the different wavelengths are interpreted by the brain as colours
Pupil
-circular hole through which light enters the eye
Pupillary Reflec
-response to light that allows light to enter in lesser amounts
Cornea
-part of the eye containing transparent cells that focus light on the retina
-80% of eyes focusing power
-fixed in place
Lens
-part of the eye that changes curvature to keep images in focus
-other 20% of focusing power
-flexible, adjusts to focus light
Accommodation
-changing the shape of the lens to focus on objects near or far
-ciliary muscles change curvature of lens
Myopia
-nearsightedness
-see close objects clearly
-results when images are focused in front of the retina
-cornea too steep or eye too long
-most common need for glasses in adults
Hyperopia
-farsightedness
-can’t see objects close
-image is focused behind retina
-cornea is too flat or eye
is too short
Presbyopia
-loss of flexibility in the lens due to aging
Close Object
-lens gets rounder
Distant Object
-lens get flatter
Near Point
-the limits of accommodation
-the point at which the lens can no longer adjust
-image stays blurry
Retina
-membrane at the back of the eye responsible for converting light into neural activity
Fovea
-central portion of the retina
-responsible for acuity
-have no rods but many cones
Acuity
-sharpness of vision
Photoreceptors
-line the retina
-process info and send it to the brain
Rods
-receptor cells in the retina allowing us to see in low levels of light
-also peripheral vision
-more plentiful
-long and narrow
-allow us to see basic shapes and colours
Dark Adaptation
-time in dark before rods regain maximum light sensitivity
Cones
-receptor cells in the retina allowing us to see in colour
-less numerous
Photopigments
-chemicals that change following exposure to light
Why are there more rods?
-they cover more space along the retina
Rhodopsin
-photopigment in rods
-vitamin A used to make
Optic Nerve
-nerve that travels from the retina to the brain
Blind Spot
-region of the retina containing no rods
-completely devoid of sense receptors
Simple Cells
-cells in the visual cortex
-“yes-no” responses to slits of a specific orientation
Complex Cells
-cells in the visual cortex
-orientation specific
-responses are less specific to one location
Feature Detection
-cell that detects lines and edges
Trichromatic Theory
-idea that colour vision is based on our sensitivity to three primary colours (red, green, blue)
Colour Blindness
-can’t see all colours
-usually due to absence of one or more types of cones-explained by trichromatic theory
Trichromats
-normal humans
-have all 3 kinds of cones
Dichromats
-only see 2 kinds of cones
-normal for some species
-considered colourblindness in others
Monochromats
-only see one kind of cone
-no colour vision
Opponent Process Theory
-theory that we perceive colours in terms of three pairs of opponent colours
-blue and yellow and red and green
-explains afterimages
Afterimages
-when you look at a colour for too long and look away, you may see the same image in a different colour
-not explained by trichromatic theory
Dual-Process Theory
-both trichromatic theory and opponent-process theory explain colour vision
Shape and Contour
-Hubel and Weisel in the 1960’s found other cells that fire to certain patterns
Visual Agnosia
-deficit in perceiving objects
-can tell shape and colour but not recognize or name the object
Audition
-our sense of hearing
Sound
-a vibration/mechanical wave that travels through a medium (usually air)
-no sound in a vacuum (space)
Frequency (Pitch)
-corresponds to the frequency of the wave
-rate at which waves vibrate
-higher frequency = higher pitch
-measured in Hz
Amplitude (Loudness)
-the intensity of the sounds
-measured in dB
Complexity (Timbre)
-sounds are a mixture of frequencies
-the quality or complexity of a sound
-info about the nature of a sound
Perceived loudness ________ about every 6-10dB
doubles
Pinna
-part of the ear we see
-skin and cartilage flap
-funnels sound waves to the eardrum
Ossicles
-3 tiny bones that amplify the force of the sound waves on the eardrum
Cochlea
-in the inner ear
-converts vibration into neural energy
-filled with fluid
Organ of Corti
-tissue containing hair cells that are necessary for hearing
Basilar Membrane
-membrane supporting the organ of corti and hair cells in the cochlea
Pitch Perception
-processed by primary auditory cortex
Hair cells at the base of the basilar membrane are most excited by ____-pitched tones
high
Hair cells at the top of the basilar membrane are most excited by ____-pitched tones
low
Place Theory
-a specific place along the basilar membrane matches a tone with a specific pitch
Frequency Theory
-rate at which neurons fire the action potentials affect perception of pitch
-works for tones up to 100Hz
-Volley theory for higher pitches
Conductive Deafness
-due to malfunctioning of the ear
-esp. failure of eardrum or ossicles
Nerve Deafness
-due to damage of the auditory nerve
Hearing loss can be A)___ or B)___
-noise-induced
-age-related (presbycusis)
Olfaction
-our sense of smell
-chemical sense
Gustation
-our sense of taste
-chemical sense
-gustatory receptors are clusters of taste cells found in taste buds
Papillae
-bumps on the tongue that contain many taste buds
-for 5 flavours: bitter, sweet, salty, sour, umami (meaty/savoury)
Taste Perception
-depends on complex patterns of neural activity
-preferences are innate and automatically regulated, but usually learned
Gustatory Cortex
-taste related area in the brain
-also reach somatosensory cortex (texture) and limbic system
Taste Variations
-people are variably sensitive to taste
-not everyone has the same experience
Smell Perception
-receptors are olfactory cilia
-located in upper portion of nasal passages
-experiences guide our perceptions
Volatile Organic Compounds (VOCs)
-chemical stimuli that are carried in the air
Pheromones
-odourless chemical that serves as a social signal to members of one’s species
-may be signals for mating, menstruation
Flavour
-the combination of taste and smell
Somatosensory System
-responsible for the sensation of touch, temperature, and pain
Nociception
-perception of pain and temperature
Hapsis
-perception of objects using touch and pressure
Proprioception
-knowledge of the position of your limbs in space
Balance
-controlled by the vestibular system in the inner ear
The Skin
-largest organ in the body
-contains receptors for pain and touch
-important role in defense
Epidermis
-outermost layer of the skin
-dead skin cells
Dermis
-below the epidermis
Subcutaneous Layer
-layer below the dermis
Referred Pain
-damage to internal organs causes pain in other locations
Mechanoreceptors
-touch, pressure, temp receptors
-specialized nerve endings in the skin
-distributed unevenly across skin
Free Nerve Endings
-similar to mechanoreceptors
-used lots for pain
Touch and Pain Perception
-info about the stimuli travels in somatic nerves then spinal cord
-touch travels faster than pain
-activate spinal reflex before traveling to brain
Nociceptive Pain
-pain caused by activation in the free nerve endings in skin
Inflammatory Pain
-pain caused by damage to tissues and inflammation of joints or by tumour cells
Neuropathic Pain
-pain caused by lesions or other damage to the nervous system
Fast Pathway (A-delta)
-myelinated
-respond to pressure
-sensation of sharp, localized, fast pain
Slow Pathway (C fibre)
-unmyelinated
-dull, diffuse, aching, burning, delayed pain
Gate Control Model
-idea that pain is blocked from consciousness by neural mechanisms in the spinal cord
Proprioception
-our sense of body position
-sense muscle stretch and force
Vestibular System
-sense of equilibrium or balance
-also in inner ear
Semicircular Canals
-three fluid-filled canals in the inner ear
-responsible for sense of balance
