Mkgrady8 Neuro 2 The Visual Pathways

Front 1

in general the primary visual pathway is made up of

Back 1

2 neuron pathway; retinal ganglion cells whose axons synapse in lateral geniculate nucleus (LGN); 2nd neuron axons form optic radiations to occipital lobe

Front 2

rods versus cones

Back 2

rods= higher sensitivity, low light levels, monochromatic, peripheral vision (peripheral retina); cones= bright light, color, detailed central vision (macula)

Front 3

normal color vision is what

Back 3

trichromatic aka requires all 3 types of cones (red, green, and blue)

Front 4

dichromats

Back 4

difficulty distinguishing between 2 different colors; most common form is a red/green deficiency (problem with red or green pigment)

Front 5

monochromats

Back 5

only see the world in grey; have only one cone pigment, or no cones and just rods, or even a cerebral deficit

Front 6

what is dyschromatopsias and what are the 2 types

Back 6

inability to distinguish colors aka color blindness; hereditary= 5-6% of males have some color vision loss, usually is a red/green discrimination deficit, X-linked inheritance pattern; acquired= can be red/green or blue/yellow discrimination defect, sign of macular disease or optic nerve disease, e.g. optic neuritis

Front 7

ishihara plates

Back 7

those color dot circles with the different colored dots tracing out a number; 'tell me what number you see if any'

Front 8

the retinal ganglion cells have projections to where?

Back 8

lateral geniculate nucleus (which then goes to occipital cortex) (vision), or hypothalamus (suprachiasmatic nucleus) (circadian rhythms), or superior colliculus (coordination of head and eye movements), or pretectum (pupillary light reflex); HE SAID THESE ARE VERY IMPORTANT YOU NEED TO KNOW THESE

Front 9

the pupillary light reflex path

Back 9

optic nerve --> optic chiasm --> crossing over occurs --> pretectum --> crossing over occurs --> edinger-westphal nuclei in pretectum --> joins CN3 --> ciliary ganglion --> pupillary sphincter muscle; so the input of bright light of course going to the occipital lobe but there is also a projection to this EW nucleus which then sends its own projection to the sphincter to constrict; keep in mind that this is partly the same tract as regular vision so there is crossing over so you do see some constriction in the eye that didn't have the pen light shown into it; HE SAID WE DO NEED TO KNOW THIS PATH AS WELL

Front 10

the pituitary sits in what bony depression of the skull?

Back 10

sella turcica

Front 11

the sella turcica is formed by what bone?

Back 11

sphenoid

Front 12

how would a pit tumor cause bitemporal hemianopsia?

Back 12

upward expansion interrupts crossing fibers in optic chiasm

Front 13

what is a quick, inexpensive method to test visual fields?

Back 13

confrontational method

Front 14

blood supply of retina and optic nerve

Back 14

OPTHALMIC ARTERY; KNOW ALL THESE BLOOD SUPPLY QUESTIONS BECAUSE HE SAID IT WILL PROBABLY BE ON THE TEST

Front 15

BLOOD SUPPLY OF OPTIC CHIASM

Back 15

BRANCHES FROM CIRCLE OF WILLIS

Front 16

BLOOD SUPPLY OF OPTIC TRACTS AND LGN

Back 16

ANTERIOR CHOROIDAL

Front 17

BLOOD SUPPLY OF OPTIC RADIATIONS

Back 17

MIDDLE AND POSTERIOR CEREBRAL

Front 18

BLOOD SUPPLY OF VISUAL CORTEX

Back 18

POSTERIOR CEREBRAL

Front 19

where does integration of input from both eyes occur

Back 19

mixing of the pathways doesn't occur until the occipital lobe (there is crossing over beforehand but the paths are still kept segregated)

Front 20

what is binocular vision?

Back 20

steropsis aka depth perception which requires good visual acuity in each eye and good alignment; occurs by 3-6 months

Front 21

what is strabismus?

Back 21

MISALIGNMENT of ocular axes; if this occurs in a baby it can be hard to form binocular vision

Front 22

what is amblyopia?

Back 22

poor vision in an eye due to 'damage' to visual centers in the brain for that eye; the damage is the result of abnormal visual stimulation during the SENSITIVE PERIOD of visual development; one or sometimes both eye(s) will not have good visual acuity even after glasses correction; causes= SAD= Strabismus (misalignment), Asymmetry (e.g. refractive error), or Deprivation (e.g. cataract)

Front 23

the secondary vision centers and what they are concerned with

Back 23

temporal cortex for object recognition (damage here causes visual agnosia, lesions do not result in loss of visual acuity); parietal cortex for visually guided behavior (lesions do not result in loss of object recognition or in loss of visual acuity)

Front 24

what does the lens do to the visual info? and what about the info that reaches the brain?

Back 24

inverts and reverses the image on the retina; optic chiasm ensure that left vision goes to right brain and right vision goes to left brain

Front 25

different parts of vision in the occipital lobe

Back 25

superior of the calcarine fissure is the inferior part of our vision (the floor if you will) and inferior of the calcarine fissure is the superior part of our vision (the sky if you will); posterior part of occipital lobe is the central (macular) vision) and anterior part of occipital lobe is the peripheral vision

Front 26

KNOW THE LESIONAL DEFICITS SLIDE

Back 26

SLIDE 61

Front 27

visual field defect: SCOTOMA definition

Back 27

a small defect

Front 28

visual field defect: ANOPSIA definition

Back 28

a large defect like hemianopsia

Front 29

VISUAL ACUITY DEFINITION

Back 29

ability to see detail as measured on eye chart

Front 30

DYSCHROMATOPSIAS DEFINITION

Back 30

inabillity to distinguish colors 'color blindness'

Front 31

PERIPHERAL VISION DEFINITION

Back 31

detection of form and movement in outer visual fields

Front 32

AGNOSIA DEFINITION

Back 32

inability to recognize or name objects

Front 33

AMBLYOPIA DEFINITION

Back 33

poor vision in one or both eyes do to problems during visual development

Front 34

STRABISMUS DEFINITION

Back 34

misaligment of the eyes, can be a cause of amblyopia

Front 35

DIPLOPIA DEFINITION

Back 35

double vision, perception of 2 images form a single object