Vision and Eye movements

Question 1

what is the coloured part of the eye?

Answer 1

the lens

Question 2

what eye structure receives light from the lens?

Answer 2

the retina

Question 3

what is analogous to the skin?

Answer 3

the retina

Question 4

where are photoreceptors within the eye located?

Answer 4

in the peripheral retina

Question 5

what are photoreceptors analogous to?

Answer 5

mechanoreceptors in the skin

Question 6

what do photoreceptors respond to?

Answer 6

a change in light

Question 7

what are the types of photoreceptors?

Answer 7

rods and cones

Question 8

where are rods primarily found?

Answer 8

the peripheral part of the retina

Question 9

what does it mean that rods are achromatic?

Answer 9

the don’t sense colour

Question 10

what helps us to see in low levels of light?

Answer 10

rods

Question 11

are there more rods or cones?

Answer 11

rods! 20:1 ratio

Question 12

where are cones found in the retina?

Answer 12

centre of the retina (fovea)

Question 13

what lets us see colour?

Answer 13

cones

Question 14

what is the region of the retina where axons are leaving?

Answer 14

optic disk

Question 15

where in the eye are there no photoreceptors?

Answer 15

in the optic disk (blind spot)

Question 16

is the blind spot the same in both eyes?

Answer 16

no

Question 17

where does most of our vision come from?

Answer 17

macula

Question 18

what eye structure is responsible for detailed vision?

Answer 18

fovea

Question 19

where does all the high acuity vision occur?

Answer 19

in the center of the retina

Question 20

what are the 2 types of ganglia in the ganglion cell layer of the eye?

Answer 20

parasol ganglion cells

midget ganglion cells

Question 21

what are characteristics of parasol ganglion cells?

Answer 21

large cell bodies, receptive fields, axons

Question 22

what are the characteristics of the midget ganglion cells?

Answer 22

small cell bodies, receptive fields, axons

fine visual detail and colour

more numerous

Question 23

what demographic often has macular degeneration?

Answer 23

people with diabetes
older individuals

Question 24

what eye structure is impacted with macular degeneration?

Answer 24

macula

Question 25

what does macular degeneration look like?

Answer 25

central vision affected

Question 26

what causes diabetic retinopathy?

Answer 26

excess blood sugar damages retinal blood vessels

Question 27

what does diabetic retinopathy look like?

Answer 27

patty vision loss throughout the visual field

Question 28

what is cataracts?

Answer 28

blurring of the lens or a clear coating over the eye

Question 29

what causes glaucoma?

Answer 29

increased intraocular pressure

Question 30

what eye structure is damaged in glaucoma?

Answer 30

the optic nerve so often peripheral deficits (looks like a spot light)

Question 31

once information leaves the eye where does it end up in the brain?

Answer 31

primary visual cortex

Question 32

as visual information comes into the eye, what happens to it?

Answer 32

it gets reversed and flipped upside down

Question 33

where do 60% of fibres cross?

Answer 33

optic chiasm

Question 34

what does the optic nerve turn into after the optic chiasm?

Answer 34

optic tract

Question 35

does the left optic tract contain fibres from the left or right eye?

Answer 35

both! optic tracts have information from both eyes

Question 36

where is the visual system going through the thalamus?

Answer 36

lateral geniculate bodies

Question 37

what are the magnocellular layers of the thalamus responsible for?

Answer 37

motion and spatial analysis (information received from the parasol ganglion cells)

Question 38

what are the parvocellular layers responsible for?

Answer 38

detailed form and colour (information from the midget ganglion cells)

Question 39

what is the conscious visual system?

Answer 39

retina-geniculate pathway

Question 40

why are the extrageniculate pathways named that?

Answer 40

because they do not go to the thalamus

Question 41

what are the subconscious visual systems?

Answer 41

extrageniculate pathway

Question 42

what is the purpose of the pretectum subcortical region?

Answer 42

controls the pupillary light reflex

Question 43

what is the function of the superior colliculus subcortical region?

Answer 43

controls orienting eye movements?

Question 44

what is the function of the hypothalamus subcortical region?

Answer 44

regulates circadian rhythms

Question 45

what artery supplies the occipital lobe?

Answer 45

posterior cerebral artery

Question 46

where is the primary visual cortex located?

Answer 46

in the occipital lobe

Question 47

what does the where pathway do?

Answer 47

analyses where something is in space

Question 48

where does the where pathway go?

Answer 48

up to the parietal lobe

Question 49

where does the what pathway go?

Answer 49

to the temporal lobe

Question 50

what happens at the what pathway?

Answer 50

information about form and colour is processed

Question 51

a lesion in what area of the brain can result in an inability to recognize faces?

Answer 51

right inferior temporal lobe

Question 52

what is the medical term for the inability to recognize faces?

Answer 52

prosopagnosia

Question 53

what muscles move the eyes laterally or medially?

Answer 53

lateral and medial rectus

Question 54

what muscles move our eyes up and down?

Answer 54

superior and inferior rectus

Question 55

what muscles turn our eyes in the socket?

Answer 55

inferior oblique (extorsion: turn our eyes out) superior oblique (intorsion: turns the eyes in)

Question 56

what is the key difference between skeletal muscles and eye muscles?

Answer 56

skeletal muscles are controlled by spinal nerves, eye muscles are controlled by cranial nerves

Question 57

what are the brainstem gaze centres?

Answer 57

responsible for the automatic control of our extra ocular muscles

Question 58

what do the brainstem gaze centers do?

Answer 58

direct the movement of the eyes (they coordinate the left and right eyes to move together)

Question 59

what does conjugate gaze mean?

Answer 59

both eyes move at the same time in the same direction

Question 60

what is the actual name of the horizontal gaze center?

Answer 60

PPRF

Question 61

what is the main function of the MLF?

Answer 61

it is yoking the two eyes together

Question 62

what does it mean that saccadic eye movements are ballistic?

Answer 62

once you start a saccade in a direction, you don't stop until you've rested on the object of interest

Question 63

what are the purpose of saccadic eye movements?

Answer 63

to bring targets of interest into our central vision

Question 64

what are saccades directed by?

Answer 64

our gaze enters

Question 65

what controls our saccades?

Answer 65

superior colliculus frontal eye fields

Question 66

what communicates with the PPRF to set off the horizontal eye gaze?

Answer 66

superior colliculus and frontal visual fields

Question 67

how do we track an object that's moving?

Answer 67

smooth pursuits

Question 68

can we do a smooth pursuit without a moving stimulus?

Answer 68

no

Question 69

smooth pursuits occur via which pathway?

Answer 69

the 'where' pathway

Question 70

what is optokinetic nystagmus a combination of?

Answer 70

saccade and smooth pursuit

Question 71

what is another term for optokinetic nystagmus?

Answer 71

"train nystagmus"