chapter 2-the first steps in vision

Question 1

light

Answer 1

narrow band of electromagnetic radiation that can be conceptualized as a wave or a stream of photons

Question 2

waves

Answer 2

property of light; color and reflection (and refraction)

Question 3

photons

Answer 3

packets of energy/ligh

low light situations and absorbing

Question 4

ray

Answer 4

light travels in particular direction

Question 5

energy varies with

Answer 5

wavelength

Question 6

visible light between ___ and ___ nm

Answer 6

400 (violet, more energy), 700 (red, less energy)

Question 7

absorbed

Answer 7

energy that is taken up, not transmitted at all, necessary for detection

Question 8

scattered

Answer 8

energy that is dispersed in an irregular fashion; less focused, atmosphere

Question 9

reflected

Answer 9

energy that is redirected when it strikes a surface, needed to see nonlight sources

Question 10

transmitted

Answer 10

energy that is passed on through a surface, without much alteration of direction

Question 11

refracted

Answer 11

energy that is altered as it passes into another medium, focusing, good thing-lenses

Question 12

cornea

Answer 12

front of eye, transparent cells (no blood vessels), refraction, transmitted

Question 13

pupil

Answer 13

hole that light goes though, center of iris

Question 14

iris

Answer 14

muscle that controls the width of pupil and the amount of light, absorbs light (not useful), reflect (eye color)

Question 15

lens

Answer 15

transparent cells, refraction, control shape to focus

Question 16

retina/fovea

Answer 16

sensation, absorb, transduction, location of photoreceptors

Question 17

presbyopia

Answer 17

old age relatedd vision loss, stiffening of the lens

Question 18

refraction is necessary to focus light rays onto the ___ and this is accomplished by the ____

Answer 18

retina, lens

Question 19

accommodation

Answer 19

process in which lens changes its shape, altering its refractive power, focus image on retina, most useful for up close objects, moves image point forward

Question 20

emmetropia

Answer 20

happy condition of no refractive error

Question 21

way the lens refracts light causes point of focus of the image to be in front of or behind the retina

Answer 21

problems of refraction

Question 22

myopia

Answer 22

nearshightedness, when light entering the eye is focused in front of the retina, and distant objects cannot be seen sharply
eyeball too long for given refractive power, too much power

Question 23

hyperopia

Answer 23

when light entering the eye is focused behind the retina, farsightedness
eyeball is too short given refractive power, not enough power

Question 24

accommodation cans what refraction problem

Answer 24

hyperopia

Question 25

resolution

Answer 25

the ability of the eye to resolve fine spatial detail in the image

Question 26

sensitivity

Answer 26

ability of the eye to respond at very low levels of retinal illumination

Question 27

____ requires distinguishing between responses of nearby receptors; subtractive differentiation

Answer 27

resolution

Question 28

___ is improved by summing responses across nearby photoreceptors; grouping things

Answer 28

sensitivity

Question 29

photoreceptors

Answer 29

cells in the retina that initially transduce light energy into neural energy

Question 30

rods

Answer 30

photoreceptors that are specialized for night vision; respond well in low luminance conditions, not process color

Question 31

cones

Answer 31

photoreceptors that are specialized for daylight vision, fine visual acuity and color, best in high luminance conditions

Question 32

center of the retina, packed full of cones

Answer 32

fovea

Question 33

age related macular degeneration

Answer 33

central part of vision deteriorates

Question 34

dry macular degeneration

Answer 34

less individual photoreceptors,

Question 35

wet macular degeneration

Answer 35

wide loss of photoreceptors because of fluid release

Question 36

bipolar cells

Answer 36

exist between photoreceptors and ganglion cell, transmits information; vertical movement

Question 37

amacrine cells

Answer 37

makes synaptic contacts with bipolar cells and ganglion cells; spread horizontally; enhancement and temporal sensitivity

Question 38

horizontal cells

Answer 38

lateral inhibition, influence overall light response

Question 39

___ and ___ form lateral path in the retina

Answer 39

amacrine and horizontal cells

Question 40

rod bipolars are all ___ cells, connect rods to ___ cells, and then connect to ON or OFF cone bipolars

Answer 40

ON, amacrine

Question 41

ON bipolar cells

Answer 41

activated by the presence of light

Question 42

OFF bipolar cells

Answer 42

activated by offset/absence of light

Question 43

diffuse bipolar cell

Answer 43

spread out to receive input from multiple cones

Question 44

midget bipolar cell

Answer 44

small, central in retina and receives input from 1 cone

Question 45

property: photoreceptor type fovea: periphery

Answer 45

mostly cones | mostly rods

Question 46

property: bipolar cell type fovea periphery

Answer 46

midget | diffuse

Question 47

property: convergence fovea periphery

Answer 47

low (p ganglion cells) | high (m ganglion cells)

Question 48

property: receptive field size fovea periphery

Answer 48

small | large

Question 49

property: acuity (detail) fovea periphery

Answer 49

high | low

Question 50

property: light sensitivity fovea periphery

Answer 50

low | high

Question 51

convergence

Answer 51

idea of many into few, lots of rods into less ganglion cells

Question 52

divergence

Answer 52

less onto many, cones

Question 53

vertical pathway of retina

Answer 53

photoreceptors, bipolar cells, and ganglion cells

Question 54

P ganglion cells

Answer 54

connect to the parvocellular pathway

Question 55

parvocellular pathway

Answer 55

visual acuity, color and shape processing

Question 56

temporal resolution

Answer 56

measurement with respect to time

Question 57

finer resolution _____ in size with retinal eccentricity

Answer 57

increases

Question 58

retinal eccentricity

Answer 58

the difference between the retinal image and the fovea

Question 59

M ganglion cells

Answer 59

connect to the magnocellular pathway

Question 60

magnocellular pathway

Answer 60

involved in motion processing

Question 61

poor temporal resolution but good spatial resolution

Answer 61

P ganglion cells

Question 62

good temporal resolution but poor spatial resolution

Answer 62

M ganglion cells

Question 63

spatial resolution

Answer 63

pixels

Question 64

receptive field

Answer 64

region of the retina in which stimuli influence a neurons firing rate, all the photoreceptors that will activate retinal ganglion cell

Question 65

receptive fields are sensitive to

Answer 65

different intensity of light in the center and in the surround

Question 66

light on receptive field

Answer 66

strong response

Question 67

light off receptive field

Answer 67

weak response

Question 68

center-surround receptive fields because luminance variations tend to be smooth within objects and sharp between objects, emphasize

Answer 68

object boundaries

Question 69

retinal ___cells act like a filter for information coming into the brain

Answer 69

ganglion

Question 70

center surround receptive fields most sensitive to ___ in the intensity of light

Answer 70

differences

Question 71

looking at different from center and surround

Answer 71

resolution

Question 72

sums across the center

Answer 72

sensitivity