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Phase 1 - S4 Nervous System > The Eye > Flashcards

Flashcards in The Eye Deck (31)
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1

what is the function of the retinal pigmented epithelium

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

2

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

rods
cones
horizontal cells

3

what do rods do

responsible for black and white vision

4

what do cones do

responsible for coloured vision and high definition

5

what do horizontal cells do

responsible for lateral inhibition

6

what are the layers of the retina

Pigmented layer and Neural layer

7

what region of the retina contains no photoreceptor cells

the blind spot where the optic nerve leaves

8

what is the macula responsible for

central vision and acuity

9

what type of photoreceptor is abundant in the macula

cones

10

what artery supplies the retina

central retinal artery

11

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

it will swell

12

describe the light reflex

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

13

in what area are the edinger westphal nuclei found

pretectal area

14

describe the accommodation reflex

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

15

describe the root of the optic tracts

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

16

describe the visual pathway

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

17

where do the radiations travel to

the primary visual cortex in the occipital lobe

18

what happens to the fibres at the optic chiasm

the nasal fibres decussate
the temporal fibres remain ipsilateral

19

what visual field are the nasal fibres responsible for

temporal visual field

20

what visual field are the temporal fibres responsible for

nasal visual field

21

what visual field are the superior fibres responsible fore

inferior visual field

22

what visual field are the inferior fibres responsible for

superior visual field

23

what type of visual loss occurs due to optic nerve damage

monocular blindness - cant see from the ipsilateral eye

24

what are the causes to optic nerve defects

retinoblastoma, meningioma

25

what type of visual loss occurs due to optic chiasm damage

bitemporal hemianopia

26

what fibres are affected in optic chiasm damage

nasal fibres

27

what causes optic chiasm damage

pituitary gland tumour

28

what type of visual loss occurs due to optic tract damage

left/right homonymous hemianopia

29

what are the causes to optic tract defects

neoplasia and trauma

30

what type of visual loss occurs in radiation damage

quadrantanopia