Neuroanatomy- Eye Retina

Front 1

What does the outer layer of the optic vesicle become? the inner layer?

Back 1

outer layer- retinal pigment epi; inner- neural retina

Front 2

What is the lens derived from?

Back 2

ectodermal placode

Front 3

If the mesenchyme in the eye were to not differentiate correctly, what structures might be affected?

Back 3

sclera, choroid, ciliary body and iris (partially)

Front 4

What are the layers of the cornea? What is it innervated and nurished by? What is it composed of?

Back 4

Epithelium, stroma and endothelium are layers separated by ant. and post. limiting membranes. It is composed of llamellar oriented collagen fibers. Nurished by aqu. humor and tears and innervated by Ophthalmic branch of V

Front 5

What is the limbus?

Back 5

Sclera-cornea transition zone where vessels end

Front 6

What is the role of the choroid? What is it attached to?

Back 6

It's has vascular capillary plexi that supply the pigment epithelium and outer segment of retinal receptors. It's adherent to the pigment epithelium and sclera

Front 7

Besides accomadation, what is another role of the ciliary bodies?

Back 7

produce aqueous humor (low in protein) to make metabolic supply for cornea and lens as well as maintain intraocular pressure

Front 8

What does the aqu. humor drain into?

Back 8

Canal of Schlemm (scleral venous sinus)

Front 9

What happens when the canal of schlemm is obstructed? mechanism?

Back 9

glaucoma and blindness due to increased intraocular pressure on optic nerve. Retinal veins may colapse leading to retinal edema and retinal detachment

Front 10

How does the ciliary body allow for lens accomodation?

Back 10

Contrxn of ciliary muscles decreases tension on suspensatory ligments (zonular fibers) thus increasing the curvature of lens for near vision

Front 11

What are the muscles of the iris, what do they do and what are they innervated by?

Back 11

Sphincter m. has parasympathtic innervation thru CNIII and is located near pupil margin. Radial m. innervated by sympathetic nerves from superior cervical ganglion. Iris separates anterior and posterior chambers

Front 12

What is the rigidity of lens with age called? What is the opacifying of lens with age?

Back 12

Presbyopia. Cataract

Front 13

What is the vitreous humor composed of? Where is it made?

Back 13

Composed of collagen, hyaluronic acid, wandering cells and water

Front 14

What are floaters? What happens if vitreous humor liquefies?

Back 14

Floaters are aggregations of vitreous material, normal but sudden onset indicative of retinal disease. Liquefying vit. humor can lead to retinal detachment

Front 15

What are the funxns of the retinal epithelium? What is its weakness?

Back 15

It absorbs light while decreasing reflexn, phagocytoses the outer segments of photoreceptors (connxn), and resynthesizes photopigments. It is a weak junxn with retina where retinal detachment occurs

Front 16

Where does phototransduxn take place?

Back 16

in the outer segment of the rods and cones

Front 17

What do bipolar cells do?

Back 17

conduct signal from photoreceptors to ganglion and horizontal cells

Front 18

What is the role of horizontal cells?

Back 18

contrast enhancement

Front 19

What is the role of Mueller cells?

Back 19

Maintain retinal homeostasis of ions and NTs

Front 20

Where do impulses originate in the retina?

Back 20

ganglion cells

Front 21

What is the macula lutea? What is the fovea?

Back 21

Area of acute vision, the fovea is a small pit in the center

Front 22

What does the retina look like directly along the visual axis?

Back 22

Cones>rods, ganglion and inner nuclear cell layers displaced laterally, NO blood vessels or optic nerve fibers INTERNAL to photoreceptor layer

Front 23

Where is the blind spot in the eye and why is it blind?

Back 23

Optic disc, because there are no cell layers of the retina to phototransduce light

Front 24

If the optic disc is depressed or cupped, what might this be indicative of?

Back 24

increased intraocular pressure from GLAUCOMA

Front 25

If the optid disc is bulging, what might this be indicative of?

Back 25

Papilledema, being chocked from increased intracranial pressure possibly due to a tumor

Front 26

Where do ganglion cell axons pierce the sclera? Are they myelinated or demyelinated beyond this point?

Back 26

At the lamina cribrosa, they are myelinated beyond this point

Front 27

What happens to the eye when there is intracranial pressure?

Back 27

Papilledema can occur because there is a presense of a potential subarachnoid space in the optic nerve. This can reduce axoplasmic outflow and can make axonal conduction block and edema

Front 28

What is it called when the optic nerve is inflammed? What diseases is this associated with?

Back 28

optic neuritis, associated with MS, drugs, and toxins

Front 29

The optic nerve is part of the CNS, what kind of cells does it have that make it this way?

Back 29

oligodendrocytes and astrocytes

Front 30

Where do neurons in the optic tract go?

Back 30

LGN of thalamus

Front 31

Which fibers cross the optic chiasm?

Back 31

Nasal fibers from each of the retinas

Front 32

Lesions in what artery cause issues in the optic tract?

Back 32

Middle cerebral artery

Front 33

What is the tract of fibers coming from lower field vision?

Back 33

Optic nerve-- LGN-- lateral to lateral ventricle thru the deep parietal white matter-- to the dorsal part of calcarine fissure

Front 34

Trace the tract of fibers coming from upper field vision

Back 34

Optic nerve-- LGN-- loop over temporal horn of lateral ventricle (Meyer's Loop)-- to ventral fissure of Calcrine fissure

Front 35

Where in the primary visual cortex is macular vision?

Back 35

Pole of occipital lobes