Visual Systems And Eye

Front 1

refractive media of eye

Back 1

mostly cornea

Front 2

pathway of light from outside

Back 2

light enters eye thru cornea, aqueous humor, lens, vitreous humor, retina (transudction on photoreceptor cells)

Front 3

optic nerve formation

Back 3

reticulogeniculate fibers from ganglion cells of retina

Front 4

optic tract formation

Back 4

fibers continue w/out interruption behind chiasm

Front 5

visual pathway from photoreceptors

Back 5

1) receptors (rods/cones) 2) N1 (bipolar neurons) 3) N2 (ganglion cells of retina) 4) N3 (LBG)- optic radiation 5) primary visual cortex

Front 6

course of meyers loop

Back 6

fibers form lat LGB directed downward and formard then bend back in sharp loop passing thru temporal lobe in lat wall of inferioir horn of lat ventricle n sweep posteriorly to occiptal lobe

Front 7

visual association areas

Back 7

ba 18 and 19, where interpretation occurs

Front 8

visual cortex

Back 8

ba 17, calcarine coretx, striate cortex

Front 9

where do fibers from lowermost part of optic radiation project?

Back 9

lingual gyrus at lower lip of calcarine fissue

Front 10

where do fibers from upper retinal field project to?

Back 10

cuneus, the gyrus above calcarine fissue

Front 11

where do most fibers of LGB terminate?

Back 11

cortical layer 4 of upper and lower lips of calcarine fissure on medial aspect occipital lobe

Front 12

what is scotoma?

Back 12

area of lost function in visual field

Front 13

contralateral homonymous hemianopsia

Back 13

/ total destruction of structures behind chiasm on one side caused by lesion of middle part opt

Front 14

what do lesion in front of chiasm like optic nerve cause?

Back 14

visual field losses in both eyes

Front 15

bitemporal hemianopsia

Back 15

defect in temporal visual field of each eye, lesion in middle part optic chisam caused by tumor of pituitary. dcussating fibers injured and visual impules from nasal halves blocked

Front 16

heteronymous

Back 16

booth temporal fields are affected

Front 17

homonymous hemianopsia w/ macular sparing

Back 17

caused by small lesion in occiptal lobe bc of large representation of macular vision @ occipital

Front 18

upper left quadrantic defect

Back 18

loss of vision in one quadrant bc cuneus recieves visual impules above, and linual recieves below, lesion @ right lingual gyrus or involving meyers loop cuts off visual impules from lower part of each right half each retina

Front 19

optical projects to retina cause this image

Back 19

inerverted and reversed

Front 20

upper visual field projected to?

Back 20

lower hemiretina

Front 21

where do horizontal and vertical lines that divide visual fields ass thru?

Back 21

macula lutea

Front 22

what is monocular crescent?

Back 22

lateral peripheral area of visual field w/out changing fixation of eye

Front 23

where is physiological blind spot?

Back 23

temporal side of macular area in each visual field corresponds to optic disc area w/ no rods of cones

Front 24

where is edinger-westphal nuc?

Back 24

preganglionic parasyma

Front 25

pupilllary light reflex pathway

Back 25

1) Ganglion cells of retina (project bilaterally to pretectal nuclei) 2) pretectal nucleus of midbrain (crossed in post commisure and uncrossed in rostral edinger) 3) edinger-westphal nucleus of midbrain (gives rise to preganglion parasympathetic fibers, exit midbrain w/ oculomotor nerve, synapse w/ postganglionic parasympathetic neruons of ciliary ganglion 4) ciliary ganglion of orbit gives rise to postganglionic parasympahetic fibers- innervates sphincter muscle of iris

Front 26

pupillary dilation pathway

Back 26

hypothalamus, ciliospinal center spinal cord, superior cervical ganglion

Front 27

afferent and efferent limbs pupillary light reflex pathway

Back 27

afferent CN II, efferent CN III

Front 28

3 reflex change sin accomodation reflex

Back 28

mitosis, thickening of lens, ocular convergence

Front 29

accomodation reflex pathway

Back 29

visual impusles arrive at area 17, pass to 18 and 19, descend thru optic radiation to superioir colliculus and pretectal area and relayed to 3 different areas

Front 30

where accomodation reflex relayed to?

Back 30

1) edinger-westphal nuc-> ciliary ganglion -> spinchter pupillae ms to produce pupillary constriction and to ciliary ms to produce thickening of lens 2) edingerwestphal nuc, no synapse at ciliary ganglion, episcleral ganglion where synapse occurs and to ciliary ms for thickening of lens 3) oculomotor nuc (perlia) to emdial recti ms to produce ocular convergence

Front 31

alternate pathway for accomodation reflex

Back 31

impulses from areas 18/19 go to motor cortex frontal lobe thru superior longitudinal fasciculus; corticobulbar or citrcomesencephalic fibers go to oculomotor nuc

Front 32

pupilary dilatation reflex due to severe pain or emotion

Back 32

impulse from retina - optic tract -> sup colliculus thru tectobulbar tract 1) to nuclei of facial n to supply orbicularis oculi ms to close eyes 2) from sup colliculus to ret. formation via tectospinal tract to ant horm of cervical spinal cord for arm musculature

Front 33

consensual light reflex

Back 33

influences unstimulated eye by fibers that cross in optic chiasm and post commisure of midbrain

Front 34

light reflex direct

Back 34

1) neurons in retina 2) optic nerve, chiasm, tract, bypass LBG, to brachium of sup colliculus to end in pretectal nuc 3) 2 halves pretectum interocnnected by pas thru post commissure 4) fibers pretectal project to edinger-wesphal nuclei 5) preganglionic parasym fibers pass thru oculomotor nerve synapse in ciliary ganglion w/ postganglionc neurons 6) postganglionic parasym fibers (via short ciliary n) innervate spihincter pupillae muscles

Front 35

levator palpebrae superiororis

Back 35

CN III elevation of upper eyelid

Front 36

lateral rectus

Back 36

CN 7 abduction

Front 37

medial rectus CN III

Back 37

adduction

Front 38

inferior oblique

Back 38

CN III abduction, evelvation , extorsion

Front 39

superior oblique (SO)

Back 39

CN IV abduction, depression, intorsio

Front 40

inferior rectus (IR)

Back 40

CN IIII, depression, adduction, extorsion

Front 41

superior rectus SR

Back 41

CN III elevation, adduction, intorsion

Front 42

oculomotor nuclear complex

Back 42

paired nuclei (lat nuc supply, edinger-wesphal ), midline nuclei (nuc perlia, caudal centra nuc) and association nuclei (nuc Darkscheqitsch and interstitial nuc cajial)

Front 43

what are the paired nuclei?

Back 43

lat nuc to supply SR, IR, MR, IO, edinger westphal nuc- supply sphincter pupillae and ciliary

Front 44

what are midline nuclei?

Back 44

caudal cenral nuc to supply levator palpebrae superiorirs, nucleus of perlia- convergence nuclues

Front 45

what are association nuclei?

Back 45

nucleus of darkschewitsch and interstitial nuc of cajial- vertical eye mvmts

Front 46

supranuclear mechanism of ocular mvmt?

Back 46

centers located in cerebral hemispheres and brainstem b4 imuplses reach nuclei of CN III, IV, VI

Front 47

what is frontal eye field?

Back 47

broadman area 8, center for voluntary rapid eye mvmt- move voluntarily on command-saccadic

Front 48

occipital gaze center

Back 48

located in areas 18/19 of occipital lobe- center for smooth pursuit mvmt for following slow moving objects (tracking)

Front 49

pontine gaze center

Back 49

PPRF- neurons in retc formation jus lat to abducens nuc- center for lateral gaze

Front 50

extraocular mvmt at nuclear level

Back 50

oculomotor nuc in midbrain, trochlear nuc in midbrain, abducens nuc in pons

Front 51

extraoc mvmt in infranuclear level

Back 51

oculomotor nerve cn3, trochlear n (cn 4) abducens n (cn 6)

Front 52

rimfl

Back 52

rostral interstitial nuc of MLF- ocated in pretectal region near sup colliculus- cetner for VERTIcal eye mvmt

Front 53

vertical axis for?

Back 53

abduction/adduction

Front 54

transverse axis for?

Back 54

elevation and depression

Front 55

what is antero-posterior or sagittal axis for?

Back 55

introsion and extorsion

Front 56

what is needed to permit accurate conjugate mvmts?

Back 56

12 extraoc ms, six craial nerves + nuclei, and MLF

Front 57

oculomotor nerve and eye mvmt

Back 57

loc @ midbrain @ level of sup colliculus- has oculomotor nuc complex

Front 58

trochlear n and eye mvmt?

Back 58

located @ midbrain @ level of inf colliculus- axons supply sup oblique

Front 59

abducens n and eye mvmt?

Back 59

abudcens nuc located below floor of 4th ventricle @ jnct pons/medulla- supply lateral rectus

Front 60

saccadic system fxn

Back 60

for horizontal voluntary rapid eye mvmt or vertical voluntary rapid eye mvmt

Front 61

saccdic system pathway- horizontal

Back 61

impulses frm area 8 -> corona radiata and ant limb internal capsule to reticular formation; fibers cross @ level of midbrain, proceeds to pons @ PPRF (on opp side)
-axonal outflow goes to adj abducens nuc to supply ipsilateral lateral rectus via MLF to contralateral oculomotor nuc to supply contralateral medial rectus to produce conjugate deviation of eyes

Front 62

lesion in frontal eye field

Back 62

impossilbe for patient to move eyes volitionally to opposite side

Front 63

saccadic sys pathway- vertical eye mvmt

Back 63

impusles frm area 8 on both side-> corona radiata and ant limb of internal capsule -> pretectal region @ RiMLF, some fibers do not cross, some do -> oculomotor nuclei to supply SR, IR, IO and torhclear nuc to supply SO

Front 64

smooth pursuit system fxn

Back 64

for vertical and horizontal movement