vision

Question 1

retina

Answer 1

most visual processing
receptive surface inside the eye
contains photoreceptor
captures light and front & projects detailed images of external world onto a layer of neurons

Question 2

transduction

Answer 2

conversion of 1 form of energy to another
light to neural signals

Question 3

cornea

Answer 3

transparent outer layer of eye
forms image on the retina
focus light

Question 4

refraction

Answer 4

bending of light rays by change in density of medium
eye glasses
telescopes
microscopes

Question 5

lens

Answer 5

focus an image on the retina
changes shape to fine tune image

Question 6

ciliary muscles

Answer 6

control shape of lens inside the eye
focuses image on retina

Question 7

accommodation

Answer 7

ciliary muscles adjust lens to bring nearby objects into focus

Question 8

myopia

Answer 8

nearsightedness
difficulty seeing distant objects
develops if eyeball is too long

Question 9

extraocular muscles

Answer 9

control movement of eyes

Question 10

photoreceptors

Answer 10

respond to light
rods and cones adjust to light sensitivity

Question 11

rods

Answer 11

focused in periphery of retina
low levels of light
convergence = sensitivity to weak stimuli
less acuity `

Question 12

Cones

Answer 12

focused in center of retina (fovea)
good w colors
no convergence = less sensitivity
better acuity

Question 13

photopigments

Answer 13

special receptor molectules in rods and cones that capture light

Question 14

rhodspin

Answer 14

photopigment in rods

Question 15

ganglion cells

Answer 15

class of cells in retina whose axons form optic nerve

Question 16

optic nerve (cranial nerve II)

Answer 16

collection of ganglion cell axons that extend from retina to brain

Question 17

scotopic system

Answer 17

in retina
operates at low levels of light
involves rods
very sensitive

Question 18

convergence

Answer 18

phenomenon of neural connections

Question 19

photopic system

Answer 19

system in retina
operates at high levels of light
involves cones

Question 20

Photoreceptors are hyper polarized in…

Answer 20

light
less neurotransmitter released

Question 21

photoreceptors are depolarized in …

Answer 21

dark
more neurotransmitter released

Question 22

pupil

Answer 22

opening formed by iris
allows light to enter eye

Question 23

pupil contraction

Answer 23

closing
parasympathetic division of autonomic nervous system

Question 24

dilation of pupil

Answer 24

opening
sympathetic region “fight or flight”

Question 25

iris

Answer 25

circular structure of eye
provides opening to form the pupil
surrounds pupil

Question 26

range fractionation

Answer 26

sensory systems cover wide range of intensity values
each sensory receptor cell specializes in 1 part of overall range intensities

Question 27

photoreceptor adaptation

Answer 27

tendency of rods and cones to adjust their light sensitivity to match current levels of illumination

Question 28

visual acuity

Answer 28

sharpness of vision

Question 29

fovea

Answer 29

central portion of retina
packed w/ highest density of photoreceptors
center of our gaze
high density of cones

Question 30

optic disc

Answer 30

region of retina without photoreceptors

Question 31

blind spot

Answer 31

portion of visual field from which light falls on optic disc

Question 32

optic chiasm

Answer 32

point at which parts of 2 optic nerves cross midline and project to opposite hemispheres

Question 33

optic tract

Answer 33

axons of retinal ganglion cells after they’ve passed optic chiasm

Question 34

Lateral geniculate Nucleus (LGN)

Answer 34

where most axons terminate
part of thalamus that receives info from optic tract
sends info to visual areas in occipital cortex

Question 35

optic radiations

Answer 35

axons of LGN that terminate in primary visual areas of occipital cortex

Question 36

primary visual cortex

Answer 36

region of occipital cortex where most visual info first arrives

Question 37

topographic projection

Answer 37

mapping that preserves point-to-point correspondence btw neighboring parts of space

Question 38

order of processing in retina

Answer 38

photoreceptors —> bipolar cells —> ganglion cells —> optic nerve

Question 39

receptive field

Answer 39

stimulus features that inhibit or excite cells
every level of vision has receptive field

Question 40

on center bipolar cells

Answer 40

inhibited by glutamate
in light —>Special skills activated depolarized –> more neurotransmitter released
in dark —> hyper polarized —> less neurotransmitter released

Question 41

off-center bipolar cells

Answer 41

excited by glutamate
in dark –>depolarized –> increased –> neurotransmitter release
in light –> special skills activated —> hyper polarized —> decreased neurotransmitter released

Question 42

on center ganglion cells

Answer 42

conditions w/ light —> increased firing rates
condition w/o light —> decreased firing rates
activated when light is presented to center

Question 43

off center ganglion cells

Answer 43

conditions w/ light —> decreased firing rates
conditions w/o light –> increased firing rates
activated when light is presented to periphery of cells receptive field

Question 44

on center / off surround

Answer 44

stimulation of center excites cell of interest, stimulation of surround inhibits

Question 45

off-center / on-surround

Answer 45

stimulation of center inhibits cell of interest, stimulation of surround excites

Question 46

simple cortical cells

Answer 46

cell in visual Cortex
responds to edge / bar with a particular width, orientation, and location in visual field

Question 47

complex cortical cells

Answer 47

cell in visual Cortex
needs movement to make it respond actively

Question 48

on-center receptive fields

Answer 48

light hits cone —> hyper polarized —> decreased neurotransmitter release

Question 49

off-center receptive fields

Answer 49

dark —> photoreceptors depolarized –> more neurotransmitter released