Neuroanat 10 Visual

Front 1

Sequence of how signal runs

Back 1

Eye point
Optic Nerve
Optic chiasm
LGN
Primary visual cortex (area 17)
- There also connections to the brain stem for eye movement and connections that control size of the pupil via occulomotor (its parasymp division)
- There also connections to preganglionic symp at T1 and then synapse on post ganglionic on superior cervical ganglia

Front 2

- Optic nerve characteristics

Back 2

CNS tract, oligodendorocytes for myelination, cannot regenerate

Front 3

- Optic chiasm fibers

Back 3

½ of fibers (from nasal retina) cross

Front 4

- Optic tract fibers

Back 4

ipsilateral temporal retinal fibers + contralateral nasal retinal fibers

Front 5

- LGN = fibers radiate to

Back 5

visual cortex via optic radiations which travel in the same direction and appear as a whiter bundle within the white matter

Front 6

2) Dura matter continues as

Back 6

the sclera of the eyeball. Because the eyeball is an outgrowth of the CNS.

Front 7

Subaracnoid continues as

Back 7

the choroid, it provides nutrition for outer portions of the retina.
Choroid gives rise to cilliary body

Front 8

– fovea

Back 8

= central vision, highest visual acuity, only cones; peripheral vision has greater sensitivity to light and good for motion detection

Front 9

- Bending of light towards fovea

Back 9

through cornea and lens (cornea bends the light more)

Front 10

- With age, lens does not return to proper (rounder) shape as easily ->

Back 10

need glasses to correct vision

Front 11

3) Visual axis of eye compose of

Back 11

nasal retina
temporal retina

Front 12

nasal retina

Back 12

close to nose, contains optic nerve and blind spot

Front 13

temporal retina

Back 13

Visual axis cant be at the level of the fovea because it would mean optic nerve would be there, and receptors would block the light coming in. That’s why optic nerve is at nasal level.
The retina in the eye is part of CNS.

Front 14

Embryology: Optic cup outer part collapses and becomes

Back 14

the pigmented epithelium cells at the back of the retina

Front 15

Inner cup gives rise to

Back 15

CNS or neural part of retina

Front 16

choroid is vascular layer on

Back 16

outside of retina

Front 17

- Retinal detachement

Back 17

occurs between the retinal pigment epithelium and the neural retina (layers of optic cup). Needs to be fixed promptly because metabolic support comes through here

Front 18

- Fovea is avascular, axons from fovea have primary route to

Back 18

optic disk (as a result, axons from lateral eye must go around fovea  implications for retinal problems – a larger portion of the field may be damaged by a smaller lesion because of how axons pile up and avoid the fovea, also plays a role in foveal sparing)

Front 19

- Pigment layer is the area we have

Back 19

the highest concentration of cones to see detail

Front 20

Limbus of the cornea at the level where

Back 20

where iris meets the cilliary body there are stem cells for the cornea of the epithelium.

Front 21

Ciliary body has zonular fibers that

Back 21

connect to the lens. When it contracts it releases the tension of the lens so we can see things up close

Front 22

Aqueous humorus, circulates and it goes to anterior chamber of the cornea and it exits through canal of schelemm. When theres high pressure, aqueous humor accumulation can lead to

Back 22

glaucoma

Front 23

Myoepithelim cells are arranged longitudinally along

Back 23

the iris and they are dilator muscles (sympathetic innvervation) and medially will be the circular muscle that acts as a spinther (occulomotor)

Front 24

Innervation to the sclera that conveys sensation and pain is

Back 24

trigeminal

Front 25

Bowmans membrane provides an immune barrier and it doesn’t

Back 25

regenerate well upon injury so it leads to a scar

Front 26

Stroma has uniform collagen fibers so contributes to

Back 26

transparency of cornea and depends on fluid and nutrition that goes through endothelium

Front 27

Descements membrane regenerates

Back 27

effectively and it ends where it meets the sclera, but Bowman’s does

Front 28

No blood vessels on cornea so dependent on

Back 28

the endothelium

Front 29

Greatest amount of bending the light rays will occur at

Back 29

air to cornea interface

Front 30

Lens fibers are elongated and progressively lose their cellular constituency and are covered by

Back 30

cristalline

Front 31

- Cones have 1:1 relationship with

Back 31

bipolar cells, retains visual acuity

Front 32

- Some ganglion cells have melanopsin

Back 32

responds slower than rods and cones, connected to hypothalamus for circadian rhythms and in brainstem for reflexes [ganglion cells themselves act as photoreceptors!]

Front 33

R visual hemifield corresponds to

Back 33

Nasal retina

Front 34

L visual hemifield corresponds to

Back 34

temporal retina; info from R visual hemifield -> temporal retina

Front 35

Superior visual field info path

Back 35

- LGN -> Meyer’s loop -> over lateral ventricle -> lingual gyrus ->lower cortex

Front 36

info from inferior visual field

Back 36

- LGN -> cortex (no Meyer’s loop) -> cuneate gyrus (above calcarine fissure

Front 37

- Direct radiations from dorsal retina

Back 37

dorsal cortex gyrus cuncus so cortex sees things upside down

Front 38

- Macular info reaches what percentage of retina, LGN and primary visual cortex

Back 38

1
33
50

Front 39

- Occlusion of which artery will destroy primary visual cortex?

Back 39

Posterior cerebral artery

Front 40

11) Blindspot – on nasal retina, so found in the

Back 40

TEMPORAL visual field (opposite). Ganglion cell axons exit and become myelinated in optic nerve

Front 41

What kind of cells form the myelin on these axons?

Back 41

Oligodendrocytes because it is part of CNS

Front 42

at level of LGN, input from each eye is still

Back 42

separate not integrated

Front 43

Ocular dominance columns

Back 43

cells in LGN project to primary visual cotex -> ocular dominance columns (input still separate); each column has preference for different line/angle

Front 44

- Lesion of R optic nerve

Back 44

blindness in R eye (ipsilateral eye

Front 45

- Pituitary tumor compressing optic chiasm

Back 45

bitemporal hemianopia (fibers from both nasal visual fields affected)

Front 46

- Lesion of R optic tract

Back 46

L homonymous hemianopia (contralateral visual field)

Front 47

- Tumor in temporal lobe affecting R Meyer’s loop

Back 47

pie in the sky = L superior quadrantanopia with foveal sparing

Front 48

- Lesion in lingual gyrus of R visual cortex

Back 48

 pie in the sky = L superior quadrantanopia with foveal sparing

Front 49

- Usually get foveal sparing with

Back 49

CORTICAL lesions

Front 50

analyzes where object is and what direction it is moving in

Back 50

- Dorsal upper pathway

Front 51

analyzes what object is and what color it is

Back 51

- Ventral lower pathway

Front 52

inability to recognize faces

Back 52

- Vascular accident in ventral R temporal lobe

Front 53

- Ganglion cells with melanopsin project to

Back 53

hypothalamus and suprachiasmatic nucleus for circadian rhythms, connections may reach T1 -> symp that will dilate pupil

Front 54

- Ganglion cells project

Back 54

suprachiasmatic nucleus (circadian rhythm), pretectal area, or superior colliculus (important for coordinating movement of eyes and head and accommodation of lens)

Front 55

- Edinger-Westphal nucleus

Back 55

parasymp component of CN3 ->sphincter papillae and ciliary mm

Front 56

Consensual Light Reflex

Back 56

when shine a light into eye, pupils of both eyes will constrict

Front 57

light into damaged eye does not cause either pupil to constrict, light in normal eye causes both pupils to constrict

Back 57

damaged retina/optic nerve

Front 58

light in damaged eye causes contralateral pupil to constrict, light in normal eye causes only ipsilateral pupil to constrict

Back 58

Damaged CN3

Front 59

Visual cortex supplied by

Back 59

MCA and PCA

Front 60

What part of retina is represented on occipital pole

Back 60

fovea