Visual Pathways

Question 1

what si the basic structure of the eye

Answer 1

3 layers

• sclera/cornea
• choroid/ciliary body/iris
• retina

Question 2

what is sclera

Answer 2

tough CT

Question 3

what is cornea

Answer 3

sp anteriorly of sclera

Question 4

what si the choroid

Answer 4

middle coat major vasculature and sp anteriorly

Question 5

what are the specialisations of the choroid anteriorly

Answer 5

ciliary body nd iris

Question 6

is the optic nerve middle

Answer 6

no more near nasal side

Question 7

what does lens essential do

Answer 7

focus

sparical nature turns things upside down ned backwards

Question 8

who does lens become round

Answer 8

by reducing tension in it

Question 9

what is the optic nerve myelinated by

Answer 9

oligodendrocytes

Question 10

what si the iris

Answer 10

light regulator

Question 11

what does the sclera and cornea like

Answer 11

sclera - white

cornea - transparent

Question 12

what is function choroid

Answer 12

absorbs light - prevents rfelcton

Question 13

what does ciliary body do

Answer 13

produces aq humour

Question 14

what does retina contains

Answer 14

photoreceptors - rods and cones

Question 15

where is blind spot

Answer 15

just lateral of visual field

Question 16

where is visual axis

Answer 16

in midline back to fovea

Question 17

what is fovea

Answer 17

place of highest acuity of vision

Question 18

what are th two fluid filled cavities of the eye

Answer 18

aq humour and vitreous humour

Question 19

what is the flow of humour aq

Answer 19

choroid form ciliary body which secret aq humour behind iris flow to ant chamber

Question 20

where is aq humour reabs

Answer 20

by canal o schlemm

Question 21

what happens if canal of scheme block

Answer 21

build pressure in ant chamber which pressure on lens and pressure retina - blindness - glaucoma

Question 22

what are suspensory ligament

Answer 22

fibres radiate form lens to change shape

Question 23

what are the two types of receptors

Answer 23

rods and cones

Question 24

what are rods sensitive to

Answer 24

in dark and light situation
black and white
very esnitve

Question 25

what are cones sensitive to

Answer 25

red blue green less sensitive

Question 26

what happens to cells in repose to light

Answer 26

hyperpolarises

Question 27

what do ganglion cels do

Answer 27

respond to contrast/ movement, colour/detail

Question 28

what si the topic here fibres form

Answer 28

ganglion cells

Question 29

what cells changes ganglion cell function

Answer 29

amacrine and horizontal cells

Question 30

does the optic disc have receptors

Answer 30

no

Question 31

what si the optic disc used to look at

Answer 31

at CNS coated by dura/arachnoid

Question 32

what is fovea centralise

Answer 32

point of fixation

Question 33

what happens to optic disc in papillooedema

Answer 33

clear edge becomes blurred of optic disc

Question 34

what is the vision like at fovea centralis

Answer 34

detailed high resolution colour vision | point fixation thinning of retinal layer

Question 35

what are the reason for high visual acuity

Answer 35

thing of retinal layers lack of rods high conc of cones low convergence

Question 36

what causes a blind spot at optic disc

Answer 36

lack of rods and cones

Question 37

what are the elements of visual athway

Answer 37

``` optic nerve optic chiasm optic tract lateral geniculate body - thalamus optic radiation strate cortex - primary visual cortex ```

Question 38

what is the term the axons do to get to straits cortex

Answer 38

radiate

Question 39

trace the pathway of the right visual field

Answer 39

``` imaged on left retina temporal fibres don't cross nasal fibres cross at chiasm right field rep in left optic tract relay process in LGN project to left primary visual cortex ```

Question 40

what is meyers loop

Answer 40

part of the optic radiation, sweeps back on itself into temporal lobe, just lateral to the temporal horn of the lateral ventricle.

Question 41

what happens when negotiating lat ventricle into banks

Answer 41

of calcimine sulcus

Question 42

what happens to sight inv macula when stroke

Answer 42

sustain enough blood for sparing vision but loss of peripheral vision

Question 43

what si visual processing

Answer 43

info in retina - colour, orientation, form | segregated in pathway and cortex

Question 44

what blood supply is to visual processing visual cortex

Answer 44

lately post cerebral

Question 45

what is blood supply which lead to macular sparing i stroke

Answer 45

post/middle cerebral arteries overlap at occipital lobe

Question 46

what is monocular vision

Answer 46

meaning curtain coming down altitudinal loss of vision (in one eye or two if binocular) ut optic nerve behind eye

Question 47

what is bitemporal hemaniopia

Answer 47

blindness coz outer half of both the right and left - cut at chiasm

Question 48

what is Homonymous hemianopia

Answer 48

loss of half of the field of view on the same side in both eyes cut further back form chasm one side

Question 49

what is Upper quandrantanopia

Answer 49

loss of vision in the same lower or upper quadrant cut during radiation to cortex

Question 50

what is the pupillary reflex

Answer 50

when light shine in eye pupil contract bilateral

Question 51

what happens in pupillary reflex

Answer 51

light in to pretectal region oculomotor nuclei ciliary ganglion contract pupil

Question 52

what is accommodation rfele

Answer 52

when look to distance to something close

Question 53

what does accommodation produce

Answer 53

lens thickening - ciliary muscle pupillary constriction - increase field depth convergence of eyes - medial recti

Question 54

what is 'normal vision'

Answer 54

able to focus both distant and near objects

Question 55

what is myopia

Answer 55

short sighted able to focus near unable to focus far eye ball too long treat - concave lens to diverge light

Question 56

what is hyperopia

Answer 56

long sighted unable to focus near objects able to focus distant objects eye ball relatively too short treat - convex lens to converge light

Question 57

what is presbyopia

Answer 57

normal age change gradual loss accommodation lens less elastic ciliary muscle weaker treat - convex lens t converge light

Question 58

what are saccades

Answer 58

jumps from opposite frontal eye fieldncannot do smoothly

Question 59

what are pursuit movements

Answer 59

smooth move to sep objects fixed on fovea | in assc cortex same side