B7-030 Visual System 1

Question 1

the sphincter muscle of the pupil is under […] control

Answer 1

parasympathetic

Question 2

the radial muscle of the pupil is under […] control

Answer 2

sympathetic

Question 3

aqueous humor is produced by

Answer 3

ciliary process

Question 4

aqueous humor drains into

Answer 4

canal of Schlemm

Question 5

transduce photons into neuronal activity

Answer 5

photoreceptors

Question 6

synaptic processing of visual signals occurs in the […]

Answer 6

retina

Question 7

[…] cell axons form the optic nerve (CN II) which projects to the thalamus

Answer 7

ganglion

Question 8

light rays are refracted at what locations in the eyes [2]

Answer 8

cornea (static)
lens (dynamic)

Question 9

errors in light refraction result in reduced […]

Answer 9

acuity

Question 10

if the eyeball is too short, front to back, it is […]

Answer 10

hyperopic

(far sighted)

Question 11

if the eyeball is too long, front to back, it is […]

Answer 11

myopic

(near sighted)
common in children

Question 12

cornea is misshapen, resulting in two focal points

Answer 12

astigmatism

Question 13

why is it more common for adults to become “far-sighted” as they age?

Answer 13

lens hardens with age and is unable to change shape

presbyopia

Question 14

images on the retina are […] and […] because of the path of light

Answer 14

upside down and backwards

Question 15

map of visual space on the retina

Answer 15

retinotopy

Question 16

information from the left visual field is projected to the […] cortex

Answer 16

right visual

Question 17

what is the advantage of binocular vision?

Answer 17

depth perception

(mostly overlapping visual fields)

Question 18

information from the left visual field is processed in the […] cortex

Answer 18

right

(information from the periphery is processed in the contralateral cortex)

Question 19

information from the […] visual fields must dessucate in the chiasm

Answer 19

temporal

Question 20

[…] molecules are embedded in the photoreceptor outer segment

Answer 20

rhodopsin

Question 21

rhodopsin is composed of [2]

Answer 21

retinal
opsin

Question 22

when retinal absorbs a photon, it […] from the 11-cis form to the 11-trans form

Answer 22

isomerizes

Question 23

all trans retinal triggers a conformational change in […], activating rhodopsin

Answer 23

opsin

Question 24

activated rhodopsin (metarhodopsin) is unstable, so it will […] once retinal goes back to its normal configuration

Answer 24

go back to original shape

Question 25

all-trans retinal is converted to [...]

Answer 25

retinol

Question 26

"recycling" of retinal occurs in the

Answer 26

retinal pigment epithelium

Question 27

when photoreceptors absorb photons, a g-couple protein pathway results in

Answer 27

closure of sodium channels --> **hyperpolarization**

Question 28

when light hits the retina, the membrane [...]

Answer 28

hyperpolarizes

Question 29

describe how stimulation with light reduces neurotransmitter release

Answer 29

in the dark: rhodopsin is inactive, the Na+ channels are open, the cell is depolarized, glutamate is released in the light: rhodopsin is active, Na+ channels close, cell hyperpolarizes, less glutamate is released

Question 30

[rods/cones] operates in dim light, can detect a single photon of light

Answer 30

rods

Question 31

[rods/cones] low acuity

Answer 31

rods

Question 32

[rods/cones] sacrifices acuity for sensitivity

Answer 32

rods

Question 33

[rods/cones] one type of opsin

Answer 33

rods

Question 34

[rods/cones] found in periphery of retina

Answer 34

rods

Question 35

[rods/cones] operates in bright light

Answer 35

cones

Question 36

[rods/cones] high acuity

Answer 36

cones

Question 37

[rods/cones] found in high density in fovea

Answer 37

cones

Question 38

[rods/cones] different opsins sensitive to different wavelengths of light

Answer 38

cones (allows for color vision)

Question 39

outgrowth of the diencephalon

Answer 39

retina

Question 40

in development, the future neural retina extends from the diencephalon as the optic vesicle and induces the formation of the

Answer 40

lens placode (invaginates to form the lens)

Question 41

in development, invagination of the optic vesicle results in what two layers coming into opposition?

Answer 41

pigment epithelium neural retina (these two layers can separate --> detached retina)

Question 42

what two layers of the eyeball separate during a detached retina?

Answer 42

pigment epithelium neural retina

Question 43

inner retinal layers are supplied by [...] artery

Answer 43

central retinal

Question 44

supplies blood to the photoreceptors

Answer 44

pigment epithelium

Question 45

why does hemorrhage or hyperplasia of the branches of the central retinal artery cause impaired visual acuity?

Answer 45

blood vessels obstruct light path to retina

Question 46

cause of hyperplasia of branches of the central retinal artery

Answer 46

type 2 DM

Question 47

two important features of the fovea that allow for higher visual acuity [2]

Answer 47

high density of cones "parting" of other layers so light has more direct path

Question 48

humans move both eyes so that an object of interest is focused on the [...]

Answer 48

fovea (maximizes visual acuity)

Question 49

visual system cells are tuned to detect [...]

Answer 49

contrast

Question 50

specialized sensory cells that transduce light into transmitter release

Answer 50

photoreceptors

Question 51

cells that receive input from photoreceptors, transfer to ganglion cells

Answer 51

bipolar cells

Question 52

output cells of the retina; axons form the optic nerve headed for LGN

Answer 52

ganglion cells

Question 53

the way that multiple photoreceptors synapse and converge on a bipolar cell creates [...] organization

Answer 53

center surround

Question 54

more glutamate is released in the [...]

Answer 54

dark (cell is depolarized)

Question 55

less glutamate is released in the [...]

Answer 55

light (cell is hyperpolarized)

Question 56

the LGN maintains [...] organization

Answer 56

retinotopic

Question 57

parietal lobe fibers represent the [...] visual field

Answer 57

inferior

Question 58

temporal lobe fibers (meyer's loop) represent [...] visual field

Answer 58

superior

Question 59

the [...] has a larger cortical representation at the posterior pole

Answer 59

fovea

Question 60

superior regions are represented on the [...] bank of the calcharine sulcus

Answer 60

lower

Question 61

inferior regions are represented on the [...] bank of the calcharine sulcus

Answer 61

upper

Question 62

area of the retina with the greatest density of cones

Answer 62

fovea (best visual acuity)

Question 63

damage to the upper bank of the right calcarine gyrus would result in what visual field loss?

Answer 63

left lower visual field

Question 64

damage to Meyer's loop on the right side would cause

Answer 64

left superior quadrantanopia

Question 65

why can damage to the radiation result in quadrantanopias?

Answer 65

LGN axons separate enough for them to get damaged separately

Question 66

bitemporal hemianopia defects arise from a lesion where?

Answer 66

optic chiasm