Sensation and Perception 2

Question 1

retina

Answer 1

final stop for light in eye
light-senstivie area at back of eye containing three layers: ganglion cells, bipolar cells, and rods and cones
absorbs and processes light information

Question 2

rods and cones

Answer 2

special receptor cells (photoreceptors)
respond to various wavelengths of light
receive photons of light and turn them into neural signals for brain, first to bipolar cells then ganglion cells

Question 3

bipolar cells

Answer 3

interneurons

single dendrite at one end and single axon at other end

Question 4

ganglion cells

Answer 4

axons of these form optic nerve

Question 5

rods

Answer 5

100 mil
concentrated in periphery
black, white, and gray vision
many connected to one bipolar cell so if one stimulated whole area send signals
visual acuity (sharpness) low

Question 6

cones

Answer 6

6 mil
receptors for visual acuity or ability to see fine detail
all over retina; concentrated at center where no rods exist
need light to function, work best in bright light
responsible for color vision because sense different wavelengths

Question 7

fovea

Answer 7

center of retina
no rods
cones concentrated here

Question 8

blind spot

Answer 8

place where there are no rods or cones

don’t see anything but brain fills in

Question 9

optic disk

Answer 9

place where all axons of ganglion cells leave retina to become optic nerve

Question 10

optic chiasm

Answer 10

point of crossover
info from left visual field goes to right visual cortex and vice versa
bc axons from temporal halves of each retina project to visual cortex on same side, axons from nasal halves cross over to other side

Question 11

dark adaptation

Answer 11

occurs as eye recovers ability to see when going from brightly lit state to dark state
rods
brighter light = longer to adapt
older = takes longer

Question 12

night blindness

Answer 12

person has difficulty seeing well enough to drive at night or get around in darkened room or house, because of age
vitamin A may help

Question 13

light adaptation

Answer 13

going from darkened room to brightly lit one
cones have to adapt to increased level of light
quicker than rods adapt to darkness, few seconds at most

Question 14

trichromatic “three colors” theory

Answer 14

young and helmholtz
proposed three types of cones: red cones, blue cones, and green cones
different shades of colors correspond to different amounts of light received by each of three cones

Question 15

combination of X and X that determine color seen

Answer 15

cones

rate at which cones are firing

Question 16

brown and wald

Answer 16

3 cones in retina, each sensitive to range of wavelengths and peak sensitivity that corresponds to 3 colors
short wavelength = blue violet
medium wavelength = green
long wavelength = green-yellow

Question 17

afterimages

Answer 17

occur when visual sensation persists for brief time even after original stimulus is removed

Question 18

opponent process theory

Answer 18

hiring
four primary colors: red, green, blue, and yellow
colors in pairs w/opponents (red v green, blue v yellow)
if one member of pair stimulated, other member inhibited and can’t work

Question 19

which theory is right

Answer 19

both
trichromatic explains what happens with raw stimuli, actual detection of wavelengths of light
opponent process explains afterimages and other aspects of visual perception that occur after initial detection of light from environment

Question 20

lateral geniculate nucleus

Answer 20

contains opponent process cells
part of pathway that visual info takes to occipital lobe
along with retinal cells, responsible for opponent processing of color vision and afterimage effect

Question 21

color deficient vision

Answer 21

caused by defective cones in retina of eye

monochrome color blindness, dichromatic vision

Question 22

monochrome color blindness

Answer 22

people either have no cones or cones that are not working at all
see world in shades of gray

Question 23

dichromatic vision

Answer 23

one cone that doesn’t work properly, see world with combination of two cones/colors

Question 24

red-green color deficient

Answer 24

lack of functioning red or green cones
confuses red and green
sees world in blues, yellow, and shades of gray

Question 25

blue-yellow color deficiency

Answer 25

less common

see world in reds, green, and shades of gray

Question 26

sex linked inheritance

Answer 26

color deficient vision is this
on X chromosome
more common in men