Vision III

Question 1

The lens is a _________ disc.

Answer 1

Biconvex

Question 2

The suspensory ligaments are are called ________ of ______.

Answer 2

Zonules of Zinn

Question 3

Which side of the lens has a greater curvature?

Answer 3

The posterior side

Question 4

Does the lens have blood flow?

Answer 4

No, it’s avascular

Question 5

What encloses the lens?

Answer 5

A capsule of connective tissue

Question 6

What type of protein composes the lens? How are these proteins arranged?

Answer 6

Crystallins, and these are arranged in layers like an onion

Question 7

What are cataracts?

Answer 7

A loss of transparency caused by an excess buildup of proteins

Question 8

As a person ages, ~40-45 the lens becomes less flexible, so that you can’t see as well up close. What is this called?

Answer 8

Presbyopia, or farsightedness

Question 9

What are the two cavities in the eye?

Answer 9

The anterior and posterior cavities

Question 10

What makes up the anterior cavity of the eye?

Answer 10

The anterior and posterior chambers

Question 11

Where is the anterior chamber?

Answer 11

Behind the cornea, in front of the iris

Question 12

Where is the posterior chamber?

Answer 12

Behind iris, in front of the lens

Question 13

Where is the posterior cavity?

Answer 13

Between the lens and retina (behind the retina)

Question 14

What is aqueous humor?

Answer 14

A clear fluid similar in composition to blood plasma

Question 15

Where is aqueous humor produced? Discarded?

Answer 15

Produced by the ciliary body; reabsorbed at the canal of Schlemm

Question 16

Where is the canal of Schlemm?

Answer 16

The canal of Schlemm is located at the sclera-corneal junction (encircles the cornea)

Question 17

Where in aqueous humor found?

Answer 17

In the anterior and posterior chambers of the anterior cavity.

Question 18

What is vitreous humor?

Answer 18

Gel-like in consistency, never replaced, transmits light

Supports the surface of the lens and holds the neural retina firmly against the pigmented layer

Question 19

Where is vitreous humor found?

Answer 19

In the posterior cavity.

Question 20

How long is aqueous humor around for?

Vitreous?

Answer 20

Aqueous: 30-90 minutes
vitreous: Lifetime

Question 21

What is glaucoma?

Answer 21

An increase in pressure on the aqueous humor, such as if the canal of Schlemm is blocked
Puts pressure on the retina and choroid, causing the retinal cells to die, and the optic nerve then atrophies

Question 22

What is an early sx of glaucoma?

Answer 22

An early sx is flashes of light, but sx often go undetected and irreversible damage is done

Question 23

Physically describe the retina.

Answer 23

Is the size and thickness of a postage stamp

Has rods and cones= photoreceptors

Question 24

The retina is composed of these three areas:

Answer 24

Macula lutea
Fovea centralis
Optic disc

Question 25

What is the macula lutea?

Answer 25

A small, yellow spot 3mm in diameter

Located in the exact center of the posterior retina

Question 26

Where is the fovea centralis?

Answer 26

In the center of the macula lutea

Is a small depression 0.4 mm in diameter

Question 27

What is the point of greatest visual acuity?

Answer 27

The fovea centralis.

Light is focused upon it

Question 28

How many photoreceptors are in the fovea centralis? What kind are they?

Answer 28

Has only 30,000 cones, no rods

Question 29

Where is the optic disc?

Answer 29

Medial to the macula lutea

Question 30

The ______ _____ from all regions of the retina converge at the optic disc.

Answer 30

nerve fibers

Question 31

The optic disc exits as the ______ ______.

Answer 31

Optic nerve

Question 32

Blood vessels enter and leave by way of the______ _______.

Answer 32

Blood vessels enter and leave by way of the optic nerve

Question 33

What is the “blind spot”?

Answer 33

The central artery of retina and this area contains no photoreceptors.