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Perception Test 1
Perception Test 1
197
Psychology
Undergraduate 4
08/27/2009

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Term
What is the 1st stage of perception?
Definition
Distal Stimulus--actual object or event, it is there even if you aren't present.
Term
What is the 2nd stage of perception
Definition
Proximal Stimulus--energy or substance that stimulates sensory system (you detect it)
Term
What is the 3rd stage of perception
Definition
Transduction- stimulus information/energy is transduced into neural signals. Different animals have different sensitivities to different senses
Term
What is the 4th stage of perception?
Definition
processing – neurons change and manipulate information. Like filling in a blind spot or emphasis of differences.
Term
What is the 5th stage of perception?
Definition
perception – experience of sensing
Term
What is the 6th stage of perception?
Definition
6. recognition --identifying, categorizing perceptions
Term
What is the 7th stage of perception?
Definition
Action – action modifies distal and/or proximal stimulus, starting the cycle over again
Term
What does action modify
Definition
Distal or Proximal stimulus
Term
What other factors can affect your Perception (think the diagram) ?
Definition
1. when you focus your Attention enhances processing of that feature and reduces others as well as affecting perception recognition and action
2. Knowledge (prior knowledge/experience) can affect your processing, perception, recognition and action due to you knowing where things should be etc
3. Consciousness encompasses perception recognition and action
Term
What is the stimulus for vision?
Definition
LIght
Term
what spectrum is light part of?
Definition
EM spectrum
Term
Short wavelength is
Definition
Violet/Blue
Term
Medium wavelength is what color?
Definition
Green/Yellow
Term
Long wavelength is what color?
Definition
Orange/Red
Term
Does light have a color/Hue?
Definition
NO only a wavelength, the others is perception
Term
what is a quantum?
Definition
a particle (packet) of EM energy
Term
what is a photon?
Definition
a particle of light
Term
when are quanta formed?
Definition
when electrons in atoms jump b/w stable energy states (orbitals)
Term
what is the wave description of light?
Definition
As photons travel, they generate oscillating electric and magnetic fields
Term
what determines wavelength?
Definition
Frequency of Oscillation
Term
4. SO Why do you suppose our eyes evolved to be sensitive to the wavelength range 400-700 nm and not other ranges of EM radiation?
Definition
1. Shorter or longer wavelengths tend to be absorbed or pass through. The visible range reflects most physical objects
1. The sun produces a lot of it
2. It interacts with surfaces of objects
Term
what is required of an object in order to see it?
Definition
Reflection of light
Term
what determines the appearance of an object?
Definition
how light is reflected from the object
Term
how is color determined on an object?
Definition
Second. Reflected wavelengths determine the perceived color of the object, other wavelengths are being absorbed
Term
what is white light? black?
Definition
White light is an equal mixture of all wavelengths
Black all colors are absorbed and only few are reflected
Term
what is intensity
Definition
Fourth. Intensity - determined by number of photons reflected (roughly equal to brightness)
Term
what are the 3 components of a color?
Definition
HUE (what wavelength is reflected) BRIGHTNESS (light green/dark green how much light reflected ) AND SATURATION
Term
what would happen if all light was transmitted?
Definition
it would be invisible
Term
what would happen if all light was absorbed?
Definition
black hole
Term
why don't you see a clear glass object on the dark side of the room?
Definition
b/c the clear glass is not reflecting any light
Term
what determines the perceived surface texture of an object?
Definition
1. The spatial pattern of reflected light determines the perceived surface texture of the object
Term
Define specular and Diffuse
Definition
2. Specular is Shiny and Diffuse is Rough in terms of the reflection on surface texture
Term
Is the incident angle always the same as the perceived angle?
Definition
Yes, just diffuse objects have varying incident angles
Term
What kind of animals have lateral eye placement?
Definition
Prey animals
Term
What is an advantage of laterally placed eyes?
Definition
less blind spots, but also less binocular vision
Term
What kind of animals have frontal placed eyes?
Definition
1. Like primates, cats and owls
Term
Characteristics of Frontal placement eye?
Definition
2. Large binocular areas and large Blind Spots
Term
What kind of eye muscles do we have?
Definition
1. We have two on top and bottom and two on the sides
2. The oblique muscle wrap around the top of the eye and help stabalize the eyes in the sockets
Term
What is vergent movement of the eyes?
Definition
Vergent- Eyes move in opposite directions to focus on objects at different distances (changing focus from objects at different distances)
Term
Convergent? Divergent?
Definition
Convergent- eyes move toward each other (close object)

Divergent-eyes move away from each other
Term
What is conjunctive movement
Definition
2. conjunctive --eyes move in the same direction
Term
What is Pursuit movement? Saccadic?
Definition
1. Pursuit- slow, smooth movement to maintain fixation on a movement object (requires a moving object)
2. Saccadic-fast, abrupt movement to change fixation
Term
What is the first layer of the eye?
Definition
Fibrous tunic
Term
What is and what is the function of the sclera?
Definition
1. Sclera - tough, white outer coating composed of densely packed fibers (primarily collagen)
1. Protect inner structures of eye
2. Maintain shape of eyeball
3. Keep out stray light
Reflects most light that hits it b/c it is white
Term
What is the cornea and what is the function?
Definition
2. Cornea -transparent, dome-shaped surface at the front of the eye

Focuses light onto retina (2/3 of refractive power) 2/3--70% of refractive power
Term
Where does cornea get nutrients from?
Definition
No internal blood supply gets nutrients from the aqueous humor and gets oxygen from air and nourished from tears, but it has a lot of nerve endings
Term
Why is cornea transparent?
Definition
Fibers are more orderly
Term
What is astigmatism?
Definition
when the cornea isn't spherical
Term
What is the second layer of the eye?
Definition
Vascular Tunic AKA Uvea
Term
Choroid =
Definition
- heavily pigmented layer running along the inside of the sclera
Term
Where does the choroid get its nutrient supply?
Definition
1. Blood vessels feed retina and other eye structure
Term
what is purpose of Choroid?
Definition
2. Absorbs scattered light, heavily pigmented
3. Other animals have the tapetum lucidum which assists in night vision (cats, possums etc)
Term
What is ciliary body
Definition
2. Ciliary body-spongy tissue near front of eye, produces aqueous humor, filling the anterior chamber
Term
What does the ciliary body continually produce?
Definition
Aqueous humor
Term
What is purpose of the Ciliary BOdy?
Definition
Maintains shape of cornea
Nourishes cornea and lens
Carries away waste products
Term
How is Glaucoma caused?
Definition
too much accumulation of Aqueous Humor and not enough exiting through the pores
Term
What else is in the 2nd layer?
Definition
Anterior chamber/Aqueous humor)
Ciliary muscles
Term
What is the total components of the 2nd chamber?
Definition
1.Choroid
2.Ciliary Body
3.Anterior Chamber/Aqueous Humor
4.Ciliary Muscles
5.Iris
6.Pupil
7.Lens
8.Ciliary Muscle
9.Vitreous Chamber/Humor
Term
What is the Stroma, and where is it?
Definition
It is in the Iris pigmented layer determines the color of eye (pigmented by melanin)
Term
Iris is an extension of what?
Definition
Ciliary Body
Term
Iris contains what?
Definition
Muscles controlling size of pupil
Term
What is the Circular Muscle and Radial Muscle?
Definition
Circular muscle AKA sphincter when contracts, makes pupil smaller
Radial muscle AKA dialator, when contracts makes pupil larger
Term
How much more light enters the pupil when it is large as opposed to small?
Definition
16x
Term
What is the function of the lens? How much refractive power is contained w/in lens?
Definition
capsule, epithelial layer, lens)-focuses image onto retina (1/3) of eyes's refractive power
Term
What is purpose of lens?
Definition
1. Change shape to focus on objects at different distances (accomodation)

Fat near, flat far
Term
For near objects the lens is ? Far?
Definition
2. Fat near, flat far
Term
The lens has 3 layers. what are they?
Definition
3 layers Lens Epithelial layer and Capsule
Term
What does the Ciliary Muscle do in the lens?
Definition
Contracts or relaxes to change shape of lens (accomodation)
Term
How is the lens suspended?
Definition
1. Lens is suspended by fibers (zonules of zinn) from ciliary body
Term
Far objects: Ciliary muscle, Zonules and lens
Definition
Ciliary muscle relalxes
Zonules pulled tight
Lens pulled flat
Term
Near objects,Ciliary muscle, Zonules and lens
Definition
Ciliary muscle contracts
Zonules go slack
Lens gets fat
Term
Near objects: Ciliary muscle, Zonules and lens
Definition
Ciliary muscle contracts
Zonules go slack
Lens gets fat
Term
What is description and function of the Vitreous chamber/humor ?
Definition
Behind lens is the vitreous chamber-contains vitreous humor, a jelly-like substance that helps the eye maintain its shape. With age, it liquifies, floaters accumulate in it and it may separate from retina
Term
What is the 3rd layer of the eye consist of?
Definition
Retina, Macular/fovea, Pigment epithelium, optic disk
Term
What converts the sensory input into electrical cells?
Definition
The Retina
Term
What direction do light and neural signals travel?
Definition
In opposite directions
Term
image of fixated object falls here...
Definition
Macula/Fovea
Term
Where do you have the highest concentration of photoreceptors ? Why?
Definition
Fovea and Third. Cell bodies of other neurons are displaced from fovea
Term
Are there blood vessels over the fovea?
Definition
no
Term
What is the Pigment Epithelium? What is part of?
Definition
Contains building blocks of photopigments that contain melanin.
Part of Choroid
Term
What is the optic disk ?
Definition
1. Hole, the blind spot, where blood vessels enter/leave the eye
Term
What are optical systems?
Definition
Systems that are able to form images
Term
What are 3 photosystems that occur in nature?
Definition
1. Pinhole aperture 2. Fixed lens 3. variable lens
Term
Why does a pinhole aperature get a focused image at any distance?
Definition
only one ray of light gets through the pinhole from each location on the object.
Term
What direction is the image with a pinhole aperture?
Definition
Image is upside down and backwards
Term
In a pinhole aperture what does the size of the image depend on?
Definition
The size of the image depends on the distance of the object from the aperture (also true for lenses)
Term
When the pinhole is too large in a pinhole aperture, what happens?
Definition
you get a blurry image because light is hitting multiple spots on the retina
Term
What are the two types of lens systems?
Definition
1. Variable 2. Fixed
Term
What are the two optical systems called?
Definition
1. Pinhole 2. Lens System
Term
What is the difference between the Lens system and the Pinhole System?
Definition
Pinhole: Only lets a few light rays through to form a focuses image. Lens: Aperture (pupil) lets many rays through and the lens bends (refracts) the rays so they converge to form a focused image
Term
What happens to light when it travels into a new medium?
Definition
It slows down and changes direction. Exception: When the light hits perpendicularly to the medium, it will not change direction.
Term
The amount of refraction depends on what?
Definition
1. Angle of incidence 2. The index of refraction
Term
What part of your eye has a similar index of refraction as water?
Definition
Cornea
Term
What type of lens do you see more biologically?
Definition
Convex
Term
What does a convex lens do to light rays?
Definition
Converges to form a focused image
Term
Where the image comes into focus depends on what?
Definition
1.Distance of the object from the lens 2. Curvature of the lens (fatter lens refract or bend light more)
Term
What does a concave lens do to light rays?
Definition
Diverge light
Term
What animals have a fixed lens (one that doesn't change shape)?
Definition
Octopus and Shark
Term
For a fixed lens system: Near object causes image formation where and what does this cause? Mid-distance? Far object
Definition
Near object:Image formation behind retina and causes a blurry picture Mid distance: On retina, focused Far object: In front of retina, blurry
Term
What two parts of the eye have the ability to change in order to focus an image?
Definition
Shape of our Lens
Term
Variable Lens System: For a near object the lens would be what thickness? Mid-object? Far object?
Definition
Near object: Thick Mid-Object: Middle thickness Far object: Thin
Term
What is accommodation ?
Definition
compensating for the distance of objects
Term
What is the visual angle?
Definition
Measuring the size of a retinal image
Term
What is the width of your thumb at arms length in terms of visual angle?
Definition
about 2 degrees
Term
How much visual angle is about .3mm on the retina?
Definition
one degree
Term
The visual angle of an object is larger when...
Definition
it is closer to the eye (duh)
Term
What allows us to change the thickness of our lens?
Definition
By accommodating action of the ciliary muscle which changes the ability of the lens to refract light.
Term
What happens if the retina is fixed and the distance between the retina and the lens is fixed?
Definition
There is only one distance that an object can be at and form a focused image on the retina
Term
What is the visual angle?
Definition
How we measure the size of an image on the retina
Term
What do animals do in terms of focusing an image?
Definition
Animals will move lens forward and back to accommodate for distances (moving fixed lens)
Term
The visual angle is ____ when it is closer to the eye?
Definition
Larger
Term
1 degree visual angle = ____ mm on the retina
Definition
0.3
Term
What are the four types of vision problems?
Definition
1. Natural Imperfections / Optical defects in the eye that we don't usually worry about
2. Focusing Problems that we worry about
3. Retina Problems
4. Optic Nerve Problems
Term
What is chromatic aberration?
Definition
When different wavelengths come into focus at different distances from the lens. The lens is refracting different wavelengths differently which creates a blur. Note: Short wavelengths come into focus in front of retina. Med on retina. Long behind retina.
Term
What is Spherical Aberration
Definition
Refractive power of lens is different at edges that in the middle. Causes blurriness. You would be seeing red on top and blue on the bottom (colors go with example from class)
Term
What are the 5 Natural Imperfections / Optical Defects?
Definition
1. Chromatic Aberration 2. Spherical Aberration 3. Random Variations in cornea or lens 4. Diffraction 5. Other light scatter
Term
What is random variations in cornea or lens?
Definition
Cornea or lens are not perfect and this can be anywhere from normal to severe.
Term
What is diffraction?
Definition
Photons hit edge of iris/pupil and scatter into eye (a little image degradation)
Term
What does other light scatter refer to?
Definition
Photons reflect off of other things in the eye
Term
What are the steps for Cataract surgery?
Definition
. Remove lens leaving capsule intact 2. Small slit in eyeball and use ultra sound to break up lens and suck it out of capsule. 3. Insert a plastic lens in the capsule
Term
What are the 5 focusing problems that we worry about?
Definition
1. Astigmatism 2. Cataract 3. Myopia 4. Hyperopia 5. Presbyopia
Term
What is an astigmatism?
Definition
Cornea is not spherical. Looks like a rugby ball
Term
What is a cataract?
Definition
Clouding of the lens. The lens is opaque.
Term
What delays the onset of Cataracts?
Definition
Vitamin A and E
Term
What is actually happening within the eye that causes Cataracts?
Definition
Proteins in the lens oxidate and become damage. This occurs over the course of your life. Smoking and UV increase risks.
Term
What does it mean in terms of the lens have myopia? What is this also called?
Definition
Nearsighted :Lens cannot get thin enough to focus on far objects so the image comes into focus in fron of retina.
Term
What type of corrective lens are used for nearsighted vision?
Definition
Concave correct lens
Term
What can't you see if you're myopic?
Definition
Far objects
Term
What are the two ways to be nearsighted? And what does each one mean?
Definition
1. Axial: Eye too long 2. Refractive: Cornea and lens bend light too much Note: You have different curvature on the horizontal plane then the vertical plane
Term
What does it mean in terms of the lens when you have hyperopia? What is this also called?
Definition
Farsighted:Lens cannot get far enough to focus on near objects, so image comes into focus behind retina. Lens cannot get fat enough to focus on near object
Term
What type of corrective lens is used for farsighted people?
Definition
Convex corrective lens
Term
What are the two ways to be farsighted? And what does each one mean?
Definition
1. Axial: eye too short 2. Refractive: cornea and lens bend light too little (too flat)
Term
What does it mean to have presbyopia?
Definition
It is the hardening of the lens. So you cannot focus on near objects
Term
Why does presbyopia occur?
Definition
It happens because of the accumulation of lens fibers
Term
When does lens fiber accumulation occur? What does this mean for the flexibility of the eye?
Definition
It starts when you are born. The lens continually gets less and less flexible.
Term
Define nearpoint? What happens to nearpoint as you age?
Definition
Nearpoint: closet an object can be to you and still be in focus. The older you get the farther from you the object must be.
Term
In the retina, what two types of vision systems are there?
Definition
Scotopic and Photopic
Term
What is Scotopic and Photopic?
Definition
1. Photopic System-Cone driven system
2. Scotopic System-rod driven system
Term
Where is the outer segment in the photorecptors?
Definition
Partially embedded in the retinal epithelium
Term
Which photoreceptor has disks inside the cell membrane and which are attached to cell membrane?
Definition
Rod--inside membrane
Cone--attached to membrane
Term
What are the two photopigments in the photoreceptors? What is special in Rods?
Definition
Opsin and Retinal
Rhodopsin in Rods
Term
What affects wavelength sensivity of retinal?
Definition
Opsin
Term
What controls wavelength sensitivity>?
Definition
Opsin
Term
How often are the disks (photopigment complexes) regenerated ?
Definition
about 3/hour
Term
Where are the regenerated disks formed and what happens to the old ones?
Definition
Produced at bottom released at top into pigment epithelium
Term
Describe the process of transduction.
Definition
1. Photon hits retinal
2. Retinal isomerizes (changes shape [11-cis Retianl -->all-trans retinal]) and photopigment (opsin or Rhodopsin) changes conformation-->
3. Cascade of chemical events (and retinal separates from opsin) -->
4. Neural Signal

PRCN
Term
How long does regeneration take for cones?Rods?
Definition
Cones: 6mins
Rods: 30mins
Term
What photoreceptor is inactive during the day?
Definition
Rods
Term
Describe the pigment regeneration of the photoreceptors...
Definition
1. Light hits 11-cis retinal
2.11-cis retinal isomerizes to All-Trans retinal
3. All-trans retinal separates from opsin (bleaching)
4.All-trans retinal transported to pigment epithelium
5. All-trans retinal is reduced to Vitamin a
6. Vitamin A is metabolized to 11-cis retinal
7. 11-cis retinal transported to photoreceptor outer segment
Term
What photoreceptor is unable to separate wavelength and intensity information?
Definition
Rods
Term
Rods signal _____ NOT ______
Definition
INTENSITY (BRIGHTNESS) NOT WAVELENGTH (COLOR)
Term
100 photons at at 500nm (green) wavelength is also just as intense as what other wavelength? What does this tell us?
Definition
200 photons at 450nm (blue)

Rods can only respond to intensity so colors just have different intensity based on the nature of the color (IE green photons are twice as strong as blue photons)
Term
How many photopigments are there in rods?
Definition
100 million
Term
What are the 4 types of retinal problems?
Definition
1. Retinitis pigmentosa
2. detached retina
3. Age-related macular degeneration
4. diabetic retinopathy
Term
what is retinitis pigmentosa ?
Definition
degeneration of retinal photoreceptors
Term
What happens to vision in adolescence? AKA
Definition
vision begins to deteriorate ;retinitis pigmentosa
Term
What photoreceptor goes first? Causing what?
Definition
2. Rods go first, causing tunnel vision and night blindness
Term
How does one get Retinitis pigmentosa?
Definition
nearly all cases are inherited
Term
Essentially what happens in Retinitis Pigmentosa?
Definition
Loss of peripheral vision
Term
What is detached Retina?
Definition
Retina detaches from wall of eye
Term
Why is Detached retina bad?
Definition
It disrupts the image and the retina dies
Term
What are some treatments for detached retina?
Definition
inject gas bubble to push retina back into eye or scleral buckle
Term
What is Age-Related Macular Degeneration?
Definition
loss of central vision due to degeneration of macula
Term
What are the 2 types of Age-Related Macular Degeneration? Describe in Detail.
Definition
Dry and Wet
One. In "dry" type, pigment epithelium and cones atrophy and die
Two. In "wet" type, choroidal blood vessels overgrow and leak, detaching the retina
Term
What kind of vision loss is associated with Age-Related Macular Degeneration?
Definition
Loss of Central Vision
Term
What vitamins help delay the onset of Age-Related Macular Degeneration?
Definition
Vitamins A,C,E (ACE)
Term
What is the leading cause of blindness for ppl over the age of 65 in the US?
Definition
Age -Related Macular Degeneration
Term
What is Diabetic Retinopathy?
Definition
Condition that can cause aneurisms or vessel blockage in the retina. It can Three. Also can cause neovascularization - overgroth of capillaries causes leakage, swelling, scarring, and blindness
Term
Who is most at risk for developing Diabetic Retinopathy?
Definition
Insulin dependent diabetics; 40% show some degree of DR
Term
What are some Optic Nerve Problems?
Definition
Multiple Sclerosis and Glaucoma
Term
What is MS ?
Definition
Demyelinating disease. the optic nerve (eye-brain pathway) is myelinated
Term
What happens to the optic nerve in MS? How does this disrupt vision?
Definition
1. Optic nerve can become inflamed, disrupting vision
2. One of the first symptoms is blurry vision
Term
What is Glaucoma?
Definition
Aqueous Humor is trapped in eye and Intraocular pressure builds damaging optic nerve at optic disk
Term
What cells are damaged by the pressure in Glaucoma?
Definition
Axons of Ganglion cells
Term
How many cones do we have in our photopic vision? Rods?
Definition
Cones=5-8million/eye Rods=120million/eye
Term
What degree is the rod free area in the fovea?
Definition
1.7
Term
How many degrees is the distribution of rods?
Definition
5 degrees
Term
Are there any rods in the fovea?
Definition
no
Term
What is the spectral sensivity for system peak for color? short, med, long?
Definition
560
short=420, med=530, long=560
Term
What is spectral sensitivty for Scotopic vision (system)?
Definition
500nm
Term
Photopic: intesnsity sensitivity
scotopic?
Definition
Photopic: low in dim light
scotopic: high in dim light
Term
What is the acuity of photopic vs scotopic vision?
Definition
photopic: high (lack of spatial summation)
scotopic: low (low resolution, high spatial summation)
Term
Light/dark adaptation photopic vs scotopic
Definition
Pho: Fast
Sco: Slow
Term
How is hue conveyed to the brain?
Definition
pattern of response and intensity by amount of response per cone.
Term
at 500 nm do short cones get stimulated? what color is short cones?
Definition
blue do not get stimulated at 500nm, they peak at around 450
Term
Is Rhodopsin or opsin better at absorbing wavelengthS?
Definition
Rhodopsin
Term
What is threshold intensity?
Definition
lowest detectable intensity that can be reliably seen
Term
High sensitivty = ____ threshold
Definition
Low
Term
Low sensitivity = ____ threshold
Definition
high
Term
What is spatial summation?
Definition
scotpic system has higher sensitivity to low levels of illumination
Term
Spatial summation refers to what?
Definition
how many photoreceptors are connected to an individual ganglion cell
Term
why does photopic system have greater acuity?
Definition
only one ganglion cell per photoreceptor makes 2 spots of light much easier to distinguish. 2 spots=2 cells firing in different locations
Term
why do infants have such poor vision?
Definition
inner segments in infants have a very large diameter compared to the photpigment so photons can escape without triggering the firing of a cell
Term
Is there anywhere in the retina where you can only activate cones?
Definition
Cones: Yes, the fovea.
Term
Is there anywhere on the retina where you can stimulate just rods?
Definition
no
Term
As visual activity shifts from cones to rods during dark adaptation we become less sensitive to ____ ____ and more sensitive to ___ ____
Definition
Less sensitive to long wavelengths and more to short
Term
What is purkinje shift? give an example.
Definition
Shift from cone vision to rod vision that causes an enhanced perception of short wavelengths during dark adaptation. An example of this shift is that green foliages stands out more near dusk
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