Histo and optic tracts of the eye

Question 1

Levels of the corneoscleral coat

Answer 1

first is the Sclera: thick fibrous opaque layer piereced by BVs nerves and posteriorly by the optic nerve

Corneal epithelium: nonkeratinized stratified squamous cells

Bowmans membrane: anterior base membrane

Corneal stroma: unique orientation of cells and stroma; avascular

Descemets membrane: posterior base membrane

Corneal endothelium: simple squamous epithelium facing anterior chamber

Question 2

Levels of the lens

Answer 2

Capsule: made of flexible elastic ECM

Subcapsular: lens epithelium cells on the periphery proliferate and migrate to make mature lens fibers cells

Lens fibers: filled with crystallins and lose all organelles
-central lens nucleus laid down during embryonic/fetal development

Question 3

Lens accomadation

Answer 3

lens flat to see far away = relaxation of cilary muscle to ftighten the zonular fibers

lens round to see close = tightening of the ciliary muscle to relax the zonular fibers to let the lens ball up

Question 4

What are the Retinal layers

Answer 4

Retinal pigmented layers
Photoreceptor layer
Outer limiting membrane
Outer nuclear layer: contain cell bodies of rods and cones

Outer plexiform layer
Inner nuclear layer: contains cell bodies of glial cells

Inner plexiform layer
Ganglion layer: cell bodies of ganglion cells

Layer of optic nerve fibers
Inner limiting membrane

Question 5

What is the pathway of the light and neuron signal

Answer 5

the light will travel in and go all the way back to the Pigmented epithelium (back of the retina)

then the signal will travel anterior to the nerve fiber layer and travel transversely to the optic nerve/disk

Question 6

Fovea Centralis

Answer 6

Highest visual acuity

Highest concentration of cones

absence of vessels cell bodies and axons of ganglionic and inner nuclear layer (stuff in the way of the cones and the light

Question 7

Macula Lutea

Answer 7

Surrounds the Fovea

Antioxidant properties and short wave UV filter

Protects the cones of the FOvea

Question 8

Optic Disk

Answer 8

Located at head of optic nerve

Gganglion axons from all of retina converge and dive

lack photoreceptors - only ganglion cells

Blind spot

Question 9

Temporal part of the retina will see the?

Answer 9

contralateral visual hemifield

Question 10

The nasal part of the retina will see?

Answer 10

the ipsilateral visual hemifield

Question 11

The superior retina will see?

Answer 11

The Inferior visual hemifield

Question 12

The inferior retina will see?

Answer 12

the superior visual hemifield

Question 13

What is the importance of the decussation at the optic chiasm

Answer 13

Brings information together from comparable areas of both retinas to help with depth perception

Question 14

What retinal areas cross at the optic chiasm

Answer 14

the nasal retina and its corresponding visual fields (ipsilateral visual field)

Question 15

What synapses at the Lateral genticulate ganglion

Answer 15

ipsilateral temporal retina
contralateral nasal retina

Same side visual field!

Question 16

Where do secondary neurons synapse in the optic tract

Answer 16

relay to the primary visual cortex (striate cortex) from the Lateral genticulate nucleus

Question 17

Fibers from the lower quadrant visual fields travel in what to where

Answer 17

originate from the dorsomedial portion of the LGN

pass through the retrolenticular limb of internal capsule

travel through the parietal lobe (Baums loop)

target the superior bank of the calcarine sulcus on the cuneus gyrus

Question 18

Fibers from the upper quadrant visual fields travel in what to where

Answer 18

originate in the ventrolateral portion of the LGN

pass into white matter of the temporal lobe called the meyers loop

Target the inferior bank of the calcarine sulcus on the lingual gyrus

Question 19

Where does the macula represent

Answer 19

found in the middle of the LGN and will end up in the respective upper and lower quadrants but the information will be processed most posterior on the calcarine sulcus

Question 20

Monocular blindness

Answer 20

lesion to one side of the optic nerve

Question 21

Bitemporal heteronymous hemianopia

Answer 21

lesion at the optic chiasm

lose both nasal retinal layer fields

Question 22

Ipsilateral right nasal hemianopia

Answer 22

lesion at the lateral aspect of the optic chiasm on the right side

lose the right temporal retina

Question 23

Left homonymous hemianopia

Answer 23

lesion at the right optic tract

lose the left visual world for both eyes

Question 24

Congruous

Answer 24

a deficit when the visual field loss of one eye can ve superimposed on that of the other eye (symmetrical)

Question 25

Incongruous

Answer 25

a deficit where the visual field is not symmetrical among both eyes

Question 26

Damage anterior to chiasm

Answer 26

affects the ipsilateral eye

Question 27

damage at the chiasm

Answer 27

causes heteronymous deficits

Question 28

damage posterior to the chiasm

Answer 28

causes homonymous defects

Question 29

lesion to the posterior cerebral artery affects on the

Answer 29

still have the macula vision but have left homonymous hemianopia with macula sparring