11_Neuro 2.7 Visual System 1: Peripheral Components & Eye Anatomy

Front 1

Describe where/how the pupillary sphincter and dilator muscles reside - also how they're innervated.

Back 1

Pupillary are proximal to the pupil and are radially arranged. Sympathetic opens the pupil.
Sphincter are distal to the pupil and are concentric. Parasympathetic - constriction closes the pupil

Front 2

What are the extraocular muslces attached to?

Back 2

Sclera

Front 3

Sicne the cornea does not have a blood supply, how does it receive nutrients and protection from infection?

Back 3

Tears and aqueous humor.

Front 4

What are the five layers of the cornea?

Back 4

1. Epithelium
2. Bowman's Membrane
3. Stroma
4. Descemet's Membrane
5. Endothelium

Front 5

What are the two primary functions of the cornea's endothelium layers? What purpose does its innervation have?

Back 5

1. Block the passage of foreign material
2. Provide a smooth surface that absorbs oxygen and cell nutrients from tears.
It's innervated with pain receptors

Front 6

What layer exists between the epithelium and stroma? What is it composed of and what happens if it's stratched?

Back 6

1. Bowman's membrane. Composed primarily of collagen. If scratched, can form a scar.

Front 7

What percentage of the cornea's thickness does the stroma contribute? What percentage of the focusing power? What percentage of water/collagen?

Back 7

1. 90% of cornea's thickness
2. 80% of the eyes focusing power
3. 78% water and 16% collagen

Front 8

Where does Descemet's membrane belong? What does it do? What happens if injured?

Back 8

It is a thin but strong sheet of tissue composed of collagen fibers just below the stroma. It protects. It's regenerated after injury.

Front 9

What are the two principle jobs of the cornea's endothelium? What happens if the endothelium cells are damaged?

Back 9

1. Keeps cornea clear and pump excess fluid out of the stroma.
2. If damaged, it is lost forever
3. If not functioning properly, corneal edema, blindness,

Front 10

What is the most common refreactvie error? Is the eye too long or short? Where does the image focus with respect to the retina? IS this near or farsightedness?

Back 10

Myopia. The eye is too long. The image focuses in front of the retina. This is nearsightedness

Front 11

What are the three parts of the Uvea

Back 11

1. Choroid
2. Ciliary body
3. Iris

Front 12

What are the three components of the Choroid?

Back 12

1. Vessel layer
2. Chorocapillary layer
3. Bruch's membrane

Front 13

Upon what layer of the choroid does the retinal pigmented epithelia rest?

Back 13

Bruch's membrane

Front 14

The ciliary body is an expansion of what? What three regions does it contact?

Back 14

Expansion of the stroma of the choroid near the lens. It is in contact with the vitreous body, sclera, and posterior chamber/lens

Front 15

The ciliary body has what that project to the lens. What are these projections called?

Back 15

Ciliary processes. Zonula fibers

Front 16

What fluid is the ciliary body responsible for absorbing?

Back 16

Aqueous humor is drained from the anterior chamber via trabecular meshwork.

Front 17

Describe the anterior aspect of the Iris. What does it contain?

Back 17

It is made up of the vascular, loose CT with interspersed melanocytes. The number of melanocytes determines eye color.

Front 18

The posterior surface of the iris is lined with what? What is the point?

Back 18

Pigmented epithelium. IT helps to reduce scatter.

Front 19

Upon which layer does the two muscles masses rest upon in the iris (i.e. the sphincter pupillae and the concentric pupillae)?

Back 19

pigmented epithelium

Front 20

What produces the aqueous humor? Describe the flow of the aqueous humor.

Back 20

Ciliary process. It passes from the post to anterior chamber between the iris and the lens. It is drained via trabecular meshwork. From there it passes into the canal of Schlemm.

Front 21

There are two types of Gluacoma. What are they and which is the most common?

Back 21

Primary Open Angle Glaucoma and Angle Closure Glaucoma. Open angle is the most common.

Front 22

Glaucoma is damage to the nerve. This can happen in two ways:

Back 22

1. Increased pressure
2. Normal pressure - "Normal tension glaucoma"

Front 23

What does "secondary glaucoma" refer to?

Back 23

Any case in which another disease causes or contributes to increased eye pressure.

Front 24

Describe Open-angle glaucoma.

Back 24

It is caused by to an obstruction in the drainage system of the eye.

Front 25

What is normal pressure of the eye? What is normal cup to optic disc ratio?

Back 25

12-22 mmHg; 0-1. Higher is worse.

Front 26

Describe angle-closure glaucoma.

Back 26

It is the acute form of the disease where there is poor access to the drainage system in the eye.

Front 27

Describe the three structural components of the lens

Back 27

1. Capsule - ECM surrounding lens
2. Epithelium - anterior surface of lens
3. Lens fiber - body of the lens

Front 28

The lens has lower refractive power than cornea (~ ? D) However it can do this:

Back 28

10 D
Accommodate

Front 29

Describe accommodation. What happens when some tries to focus on something near?

Back 29

The ciliary muscles CONSTRICT to relax the fibers on the lens - cause the lens to thicken. The opposite happens when trying to focus on far object.

Front 30

What are the two major components of vitreous body?

Back 30

1. Type 2 collagen
2. Hyaluronic acid

Front 31

The retina has two regions derived from different layers of the optic cup during embryogenesis:

Back 31

1. Neural or sensory retina
2. Retinal pigment epithelium (RPE)

Front 32

Name these layers

Back 32

a

Front 33

The fovea has a high concentration of rods or cones?

Back 33

Cones

Front 34

In regard to a photoreceptor, what is in the inner segment and what is in the outer segment?

Back 34

Inner: Organelles for protein synthesis and E production
Outer: Flattened membrane discs with photosensitive visual pigments.

Front 35

Describe the distribution of rods and cones

Back 35

Rods are most numerous except at fovea. They are very sensitive to light
Cones are most numerous at fovea and have membrane discs. Responsible for high acuity & color vision

Front 36

Is there a blood supply to the fovea? Why or why not?

Back 36

No. The vascularture is in the inner layers and since the fovea doesn't have an inner, it does not have a blood supply.

Front 37

What are the major functions of the RPE:
1. With respect to light
2. With respect to nutrients
3. With respect to retinal
4. With respect to outer segment
5. With respect to structural integrity of retina

Back 37

1. It absorbs scatter light
2. Transports nutrients and ions bn photoreceptors & choriocapillaris
3. Reisomerizes all-trans retinal
4. Renews outer segment ~10%/d
5. Secretion of growth factors for maintenance and structural integrity of retina

Front 38

What two vessels supply the retina?

Back 38

1. Outer retina is supplied by choriocapillaries
2. Inner is supplied by central retinal artery.

Front 39

The central retinal artery is a branch of which artery?

Back 39

The opthalmic artery

Front 40

Impaired foveal specialization is a hallmark of diseases such as: (2)

Back 40

1. Aniridia
2. Albinism.