Visual System Flashcards by Audrey Chu

what is the superior colliculus a part of? what is it importnat for?

part of the tectum

-important for orienting eyes and head to not only visual stimuli but also auditory and somatosensory stimuli

How well did you know this?

Not at all

Perfectly

where is the accessory optic nuclei?

in the midbrain tegmentum

How well did you know this?

Not at all

Perfectly

what central projections of RGCs (retinal ganglion cells) in the optic nerve are in the midbran, hypothalamus, and thalamus

midbrain: pretectal olivary nucleus, superior colliculus (tectum), accessory optic nuclei
hypothalamus: suprachaismitc nucleus
thalamus; lateral geniculate nucleus

How well did you know this?

Not at all

Perfectly

which fibers cross and which stay straight

the nasal retinal fibers crossed to the opposite brain

temporal fibers continue straight

How well did you know this?

Not at all

Perfectly

the chiasm carries _____ retinal fibers from each eye, representing the _____ field of each eye

chiasm carries nasal retinal fibers form each eye, thereby representing the temporal field of each eye

How well did you know this?

Not at all

Perfectly

the tract carries ____ fibers from the _____ retina, and the crossed _____ fibers from the contralateral retina

the tract carries the temporal fibers from the ipsi retina (ipsi nasal field) and the crossed nasal fibers from the contralateral retina (contra temp field)

How well did you know this?

Not at all

Perfectly

what are the 6 layers of the LGN

inner 2 layers called magnocellular layer
outer 4 layers are parvocellular

1, 4, 6 get info from contralateral retina (nasal)
2, 3, 5 get info from ipsi (temporal retina)

How well did you know this?

Not at all

Perfectly

what is meyer’s loop

some raidations travel inf in the temporal lobe

-these inf radiations are carrying the same field info that was carried int he inf retina which is for the sup field

How well did you know this?

Not at all

Perfectly

what is the rule of L’s (wehre do the lower retina fibers go)

lower retinal fibers, to the lateral LGN, into Meyer’s Loop, to synapse on the Lingual gyrus

How well did you know this?

Not at all

Perfectly

where does inf field info go

superior retina
superior radiations (parietal lobe)
superior bank of occipital cortex (cuneus)

How well did you know this?

Not at all

Perfectly

what separates the nasal from temporal retina

`the fovea

How well did you know this?

Not at all

Perfectly

where do distal arcuates come from

where do proximal arcutes come from

distal: come from peripheral RGCs
proximal: RGCs closwer to optic disc

How well did you know this?

Not at all

Perfectly

what kind of fibers are papillomacularbundles and where do they insert

nasal retinal fibers inserting into the temporal neuro-retinal rim
-go from the fovea (central) to ONH

How well did you know this?

Not at all

Perfectly

what kind of retinal fibers are arcuates and wehre do they insert

temporal retinal fibers that arched over the papillomacular bundle to insert into the superior-temporal and inf-temp neuro retinal rim
-some come from peripheral retina; other start out more centrally

How well did you know this?

Not at all

Perfectly

where do nasal fibers come from and where do they insert

nasal retinal fibers that insert into the nasal neuro retinal rim

How well did you know this?

Not at all

Perfectly

where do the distal arcuates travel

wehre do the proximal arcuates travel

distal: travel at the bottom of the heap (closwer to RGC layer)
proximal: travel more superficially, on top of distal fibers (closwer to vitreous)

How well did you know this?

Not at all

Perfectly

what position in the optic disc to distal arcuates occupy? proximal?

distal: occupy a more peripheral position in the optic disc (near disk margin)
proximal: occupy a more central position in the optic disc (nearer the cup)

How well did you know this?

Not at all

Perfectly

although the papillomacular bundle starts out in the temporal neuro-retinal rim, they move to occupy a …in the optic nerve

central location in the optic nerve (closer to the chiasm)

How well did you know this?

Not at all

Perfectly

a lesion in the posterior chiasm may cause a …

bitemporal hemianopia, denser below

bc the superior-nasal fibers cross in this portion of the chiasm

How well did you know this?

Not at all

Perfectly

what happens in the anterior chiasmal syndrome

causes a junctionalscotoma

centrol loss (NFB defect) in one eye and superior-temopral loss in the opposite eye
bitemporal hemianopia (due to crossing nasal fibers) is denser sup earlier on the course of the dieases

How well did you know this?

Not at all

Perfectly

where does the papillomacular bundle travel in the chiasm and where does it cross in the chiasm

travels inf in the chiasm and then crosses in the most posterior part of the chiasm

How well did you know this?

Not at all

Perfectly

what kind of disease can affect temporal fibers

aneurysm of the ICA which can push on these temporal fibers to cuase a nasal vf defect one eye

How well did you know this?

Not at all

Perfectly

what fibers are in the anteriro chiasm?
post chiasm?
what fibers are uncrossed?

ant: inf-nasal fibers (sup-temp field)
post: sup-nasal fibers (inf-temporal field)
- nasal macular fibers (papillomacular bundle)
uncrossed: temporal fibers (arcuates, temporal macular fibers)

How well did you know this?

Not at all

Perfectly

what occurs in an ant chiasmal syndrome?
classical chiasmal syndrome?
post chiasmal syndrome?

ant: juctional scotoma
classic: bitemporal field loss
post: central bitemporal
- bitemporal denser below
- incongruous homonymous hemianopia (tract)

How well did you know this?

Not at all

Perfectly

superior fibers are superior then move ____ inf fibers move _____ macular fibers are central and move ____

sup move medial inf move lateral macular fibers are central then move sup

where do the superior retinal quadrants synapse in? what kind of fibers

medial LGN uncrossed ST fibers crossed SN fibers

wehre do the inf retinal quadrants synapse in | what kind of fibers

lateral LGN uncrossed IT fibers crossed IN fibers

where do the macular fibers synapse in | what kind of fibers

intermediate LGN - sup macular fibers go to the medial aspect of the int LGN - inf macular fibers go to the lateral aspect of the int LGN

the medial LGN contain fibers destined to _____ to the parietal lobe via the ____ radiations. -represent ______ inf field info

the medial LGN contain fibers destined to head up to the pareital lobe via the sup radiations -these head to the sup visual cortex and represent contralateral inf field info

the lateral LGN contain fibers destined to _____ to the temporal lobe via the _____ radiations -these head to the _____ visual cortex and represent contralateral ______ sup field info

the lateral LGN contain fibers destined to head down to the temporal lobe via the inf radiations -these head to the inf visual cortex and represent contralateral sup field info

a right LGN lesion will cuase a _______

left homonymous hemianopia

optic radiations that go up DORSALLY to the parietal lobe carry info representing the _____ field

inf field | and sup retinal quad

optic radiations that go down VENTRALLY to the temporal lobe represent info from the _____ field

sup field | and inf retinal quadrants

what fissure separates the sup and inf visual cortex

calcarine fissure

what tip is the most posterior part wehre the macular/central vision is represented

occipital tip

what contain the axons of RGCs

retinal nerve fiber layer optic nerve optic chiasm tract

what are the 4 portions of the optic nerve

intraocular (ONH) intraorbital intracanalicular intracranial

what is the longest part of the optic nerve

intraorbital portion

what are the lengths of the papilla, intraorbital, intraosseous, and intracranial

ONH aka papilla: 1mm intraorbital: 30mm intraosseous: 6mm intracranial 10mm

what are the 3 zones of the optic nerve head (aka intraocular optic nerve and papilla)

1. prelaminar (ant) 2. laminar 3. retrolaminar (post )

what are lamina cribosa

holes through which all RGC axons pass to exit the eye --(200-300 holes) through which all optic nerve axons pass

what do axons of retinal ganglion cells become

optic nerve, chiasm, and tract

where does the central retinal artery pierce the optic nerve sheath

10-12mm behind the globe and runs ant in the central aspect of the optic nerve to emerge in the center of the optic disc

which bone is the intracanalicular portion in?

sphenoid, lesser wings

in intraorbitla part goes from behind the ____ to the _____

ONH to the optic foramen

the intracranial portion varies in length, which will afftect the position of what

of the optic chiasm over pituitary gland

what ist he optic chaism superior to? how many mm

10mm above the pituitary gland | -which sits inside the sphenoid bone-the sella turcica

the chiasm lies in the middle of the....

suprasella cistern | -CSF filled subarachnoid suprasellar cistern

the pituitary gland is inf to the chiasm, so pituitary stalk to ______ to the optic chiasm

posterior

in a craniopharyngiomas (usually at the junctin of the infundibulum and the pituitary gland) the turmos can compress the post optic chiasm, what compression can you get and what happens

you get a compression of the crossing sup nasal fibers which mediate inf temporal vision in each eye -bitemporal hemianopia denser inferiorly

the optic recess is one of the pointy parts ot he 3rd ventricle and is _____ nad ____ to the optic chiasm

right above and post to the optic chiasm

how is the chiasm located in relation to they hypothalamus

chiasm is in front of and inf to the hypothalamus

what ist he anterior and post bony boundary of the sella turcica

ant: tuberculum post: dorsum

what is a prefixed, normal, and postfixed chiasm?

normal: above the diaphrgma sellae prefixed: intracranial optic nerves are short, the optic chiasm is positioned ant and sits over the tuberculum sellae postfixed: intracranial nerves are long, the chiasm is positioned post to the dorsum sellae

if you have a postfixed chiasm where the chiasm is "fixed" to the dorsum sellae, then if the pittuitary below were to expand larger than 10mm, what would you be more likely to compress? the ant, middle, or post chiasm?

ant chiasmal syndrom/junctional scotoma

what can occur from a retrochiasmal lesion (meaning a lesion occuring anywehre starting behind the chiasm all the way to the visual cortex)

homonymous hemianopia

why can you not get an RAPD from a lesion at the LGN, radiations, or visual cortex?

pupil light reflex pathway bypasses the LGN

once the optic radiations leave the LGN, they traverse the most ______ aspect of the _______ . after this they course post to the visual cortex

most posterior aspect of the post limb of the internal capsule

why is there meyer's loop

the ventral horizontal bundle (inf optic rad) have to skirt around the inf horn of the lateral ventricle, which is in the temporal lobe

If you have a lesion to the right occipital lobe above the calcarine fissure, what kind of field defect would you expect?

left inferior HH

in the occipital lobe, if there is a lesion in the posterior region what thing will you get

highly congruous homonymous hemianopia - often respects both the vertical and horiz - a true qandrantonopia

if there is a lesion in the ant occipital lobe what will you get

monocular temporal crescent

what can be spared when there is a lesion in the occipital lobe

macula or temporal crescent may be spared | -macula represented at TIP (most post)

Visual System Flashcards

(63 cards)