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Flashcards in Visual Pathway Deck (117)
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1

centrocecal

includes fixation and the blind spot

2

scotomas

Island defect surrounded by “seeing field”

3

what is the optic chiasm surrounded by

circle of willis

4

nerve fiber bundle defect

nasal step
-Defects on the horizontal midline nasally >15 degrees away from central fixation

5

how many optic nerve fibers

1-2.2 million

6

optic chiasm relations

-Posterior + inferior to the anterior cerebral + communicating arteries
-Medial to the internal carotid arteries
-Inferior to the third ventricle
-Superior to the pituitary gland

7

striate connections
hypothalamus

circadian rhythm

8

what is the diameter of the intraorbital portion of the nerve

diameter: 3mm

9

pupils and optic tract

pupils affected if lesion is in the anterior 2/3 of the tract

10

where is the first place that a single lesion will affect both eyes

optic chiasm
nasal fibers cross the midline

11

optic radiation blood supply
middle radiations

deep optic branch of the middle cerebral artery

12

where does myelination occur

only in he postlaminar region

13

vertical organization

-ocular dominance columns
-columns for stimulus orientation
--responds to the direction of light

14

visual association areas names and functions

Brodmann areas 18, 19 now referred to as V2, V3, V4, V5

Functions as storage for visual patterns and recall

15

bitemporal hemianopia most common cause

pituitary gland adenoma

16

primary visual cortex blood supply

Calcarine branch of the posterior cerebral artery

17

superior network blood supply to optic chiasm

-Anterior communicating artery
-Anterior cerebral artery

18

LGN retinotopic representation

A given point in the visual field projects to a specific location in the LGN

Fibers from corresponding points in both retinas terminate in neighboring areas of adjacent LGN layers

19

meyers loop

-part of inferior retina (temporal)
-must pass through the temporal lobe by looping around the inferior horn of the lateral ventricle.

20

optic chiasm
superior nasal fibers

cross to the contralateral, medial optic tract
-posterior knees of wilbrand

21

what does the calcarine fissure intersect

intersects the parietooccipital sulcus

22

what is the lamina cribosa

network of scleral fibers where the optic nerve exits the eye

23

To nucleus of the optic tract

Optokinetic nystagmus (OKN)

24

superior field is imagined in

inferior retina

25

inferior nasal fibers

cross to the contralateral, lateral optic tract
-anterior knees of wilbrand

26

function of visual cortex

-Process visual information
-Integration of binocular information

27

optic tract lesions
right VF
left VF

-right vf carried in left optic tract
-left vf carried in right optic tract

28

Paracentral scotoma

Does not affect fixation

29

Hemianopia or Hemianopsia

-homonymous defect extends past the 180th meridian
-involves half the visual field
-respects the vertical midline

30

retinotopic representation visual cortex

Adjacent fibers in the LGN project to adjacent areas in the visual cortex