Visual

Question 1

the optic disc produces the

Answer 1

blind spot

Question 2

the lens functions to

Answer 2

change the refractive power (changing the shape of the lens)

Question 3

accomodatoin

Answer 3

changing of the lens to view a near object

Question 4

emmetropia

Answer 4

image of an object focused on retinal surface

Question 5

hypermetropia

Answer 5

far sightedness

Question 6

myopia

Answer 6

near sightedness

Question 7

presbyopia

Answer 7

loss of lens elasticity noted with age

Question 8

bifocals

Answer 8

corrective prescriptions that corrects for distance and for near vision

Question 9

rods

Answer 9

• low excitation threshold

- used in dim conditions

Question 10

cones

Answer 10

• high excitation threshold
• high light situations
• acuity is high
• color vision

Question 11

ganglion cell function

Answer 11

-final stage of retinal processing

Question 12

axons of ganglion cells form the

Answer 12

optic nerve

Question 13

receptive field

Answer 13

the area in visual space which , upon illumination, influences the signaling of that neuron

Question 14

sustained ganglion cells

Answer 14

cells that respond as long as the stimulus remains within the receptive field
- correspond with small ganglion cells (P)

Question 15

transient ganglion cells

Answer 15

respond only when the light is turned on or off

-correspond with large ganglion cells (M)

Question 16

P cells provide information about

Answer 16

fine detail

Question 17

Separation of the hemifields occurs at the level of the

Answer 17

optic chiasm

Question 18

contralateral homonymous perception

Answer 18

the right primary visual cortex is perceiving only the left half of the visual field

Question 19

everything caudal to the optic chiasm is carryiong only

Answer 19

contralateral homonymous sensatoin

Question 20

Hemianopia

Answer 20

loss of visual field perception of half of the entire field

Question 21

Binasal heteronymous hemianopia

Answer 21

when each eye is only able to see the ipsilateral temporal visual field not the nasal visual fields

Question 22

Optic nerve fibers from the temporal retina (nasa visual hemifield) course caudally along the

Answer 22

lateral edge of the optic nerve, optic chiasm and optic tract to the ipsilateral LGN

Question 23

Fibers from the nasal retina (temporal visual hemifield) course

Answer 23

caudally along the medial edge of the optic nerve and CROSS in the chiasm, then course along the medial edge of the optic tract to the contralateral LGN

Question 24

fibers from the upper retina (inferior or lower visual hemifield)

Answer 24

course caudally along the dorsal edge of the optic nerve, chiasm and tract

Question 25

fibers from the lower retinal (upper visual hemifield) course

Answer 25

caudally along the VENTRAL edge of this retinogeniculate pathway

Question 26

retinogeniculate fibers carrying information from more peripheral visual fields are located

Answer 26

most superficially | those carrying from the central visual fields are located more internally

Question 27

80% of the optic nerve fibers end in the

Answer 27

LGN

Question 28

20% of the optic nerve fibers end in the

Answer 28

midbrain near superior colliculus

Question 29

the LGN projects to the

Answer 29

primary visual cortex (area 17) by way of visual radiations

Question 30

those carrying information from the upper halves of both retinae course

Answer 30

directly back around lateral ventricle to the cuneus (sup. calcarine fissure)

Question 31

those carrying informatin from the lower halves of the retinae course

Answer 31

- toward tip of temporal horn of lateral ventricle - loop inferiorly- then caudally to reach inferior bank of calcarine fissure- lingual gyrus - MEYER's LOOP

Question 32

damage to meyer's loop results in

Answer 32

contralateral upper homonymous quadrantanopia

Question 33

central visual field is represented in the

Answer 33

most posterior part of the occipital lobe

Question 34

the macula of the visual field is represented

Answer 34

at the occipital pole

Question 35

the peripheral visual fields are represented

Answer 35

in a rostral direction along the calcarine fissure (cuneus and lingual gyrus)

Question 36

blood supply to the primary visual cortex is

Answer 36

posterior cerebral artery

Question 37

cells in the magnocellular layer are involved in

Answer 37

perception of dark and light contrast (M cells)

Question 38

cells in the parvocellular layer process

Answer 38

fine spatial and color information (P-cells)

Question 39

retinal ganglion cells project also to the

Answer 39

superior colliculus

Question 40

retino-collicular fibers

Answer 40

- travel to brachium of superior colliculus to termiinate there - from superior colliculus, postsynaptic fibers project to areas 18 and 19

Question 41

afferent limb of the pupillary light reflex

Answer 41

small bundle of fibers branches off in the brachium of superior colliculus

Question 42

Quadrant defects

Answer 42

first clue of temporal lobe issues

Question 43

macular sparing

Answer 43

field defects which include everything except macular field (central vision) - occurs when entire ipsilateral visual cortex is destroyed except for pole

Question 44

primary visual cortex projects to the

Answer 44

secondary and tertiary (prestriate) cortices (areas 18 and 19) then to temporal lobe--> posterior parietal lobe for perception --> parieto-temporal junction (perception of color, rotation and depth)

Question 45

correlation between areas (18,19), temporal love and posterior patietal lobe (junction of the 2)

Answer 45

allows us to percieve visual space (depth and movement) along with object specificity within the visual space)

Question 46

P cells relay information on

Answer 46

form and color to temporal lobe regions

Question 47

M cells relay information concerning

Answer 47

gross from and motion to parietal lobe areas

Question 48

lesions to primary visual cortex

Answer 48

- contralateral visual field deficit | - if bilateral subject will appear blind but will still have pupillary light reflex

Question 49

areas 18 and 19 receive projections from

Answer 49

- ipsilateral primary visual cortex - ipsilateral superior colliculus - contralateral prestriate

Question 50

lesions to areas 18 and 19

Answer 50

cause deficits in discriminating between objects or patterns

Question 51

posterior parietal lobe (Brodmann's 7) receives projections from

Answer 51

- visual association areas (M path) - ability to identify rotational and directional movements - visual and spatial orientation - position of body in space (depth)

Question 52

first level of visual system in which stimuli from both hemispheres are merged to form a single image

Answer 52

posterior half of the middle and inferior temporal gyri