The Eye

Question 1

what is the function of the retinal pigmented epithelium

Answer 1

contains melanin to ensure theres not excessive light refraction
anchors the photoreceptor cells in the neural layer

Question 2

what are the 3 types of photoreceptor cells in the neural layer of the retina

Answer 2

rods
cones
horizontal cells

Question 3

what do rods do

Answer 3

responsible for black and white vision

Question 4

what do cones do

Answer 4

responsible for coloured vision and high definition

Question 5

what do horizontal cells do

Answer 5

responsible for lateral inhibition

Question 6

what are the layers of the retina

Answer 6

Pigmented layer and Neural layer

Question 7

what region of the retina contains no photoreceptor cells

Answer 7

the blind spot where the optic nerve leaves

Question 8

what is the macula responsible for

Answer 8

central vision and acuity

Question 9

what type of photoreceptor is abundant in the macula

Answer 9

cones

Question 10

what artery supplies the retina

Answer 10

central retinal artery

Question 11

what will happen to the optic disc in raised inter cranial pressure

Answer 11

it will swell

Question 12

describe the light reflex

Answer 12

light stimulates the afferent CN II
nerve synapses with both Edinger Westphal Nuclei
efferent CN III gives a parasympathetic response causing direct and consensual pupil contraction via constrictor papillae

Question 13

in what area are the edinger westphal nuclei found

Answer 13

pretectal area

Question 14

describe the accommodation reflex

Answer 14

light stimulates the afferent CN II
nerve synapses at the lateral geniculate nucleus and goes to the primary visual cortex in the occipital lobe
efferent CN III causes convergence of pupils, pupil constriction and ciliary muscle contraction to give a more convex lens

Question 15

describe the root of the optic tracts

Answer 15

they go to the lateral geniculate nucleus in the thalamus where they then spilt into radiations

Question 16

describe the visual pathway

Answer 16

optic nerve - made up of 4 fibres from the ipsilateral eye
optic chiasm
optic tracts
radiations

Question 17

where do the radiations travel to

Answer 17

the primary visual cortex in the occipital lobe

Question 18

what happens to the fibres at the optic chiasm

Answer 18

the nasal fibres decussate

the temporal fibres remain ipsilateral

Question 19

what visual field are the nasal fibres responsible for

Answer 19

temporal visual field

Question 20

what visual field are the temporal fibres responsible for

Answer 20

nasal visual field

Question 21

what visual field are the superior fibres responsible fore

Answer 21

inferior visual field

Question 22

what visual field are the inferior fibres responsible for

Answer 22

superior visual field

Question 23

what type of visual loss occurs due to optic nerve damage

Answer 23

monocular blindness - cant see from the ipsilateral eye

Question 24

what are the causes to optic nerve defects

Answer 24

retinoblastoma, meningioma

Question 25

what type of visual loss occurs due to optic chiasm damage

Answer 25

bitemporal hemianopia

Question 26

what fibres are affected in optic chiasm damage

Answer 26

nasal fibres

Question 27

what causes optic chiasm damage

Answer 27

pituitary gland tumour

Question 28

what type of visual loss occurs due to optic tract damage

Answer 28

left/right homonymous hemianopia

Question 29

what are the causes to optic tract defects

Answer 29

neoplasia and trauma

Question 30

what type of visual loss occurs in radiation damage

Answer 30

quadrantanopia

Question 31

what is macular sparing

Answer 31

where the macula is not damaged when the occipital lobe loses its blood supply from the posterior cerebral artery as the macula is still supplied by the middle cerebral artery so you still have central vision