Visual Intro

Question 1

The visual system can sense light how far?

Answer 1

One quantum away

—seeing a candle 1 mile away

Question 2

What is the function of the eye?

Answer 2

Present an image of the external world to the photoreceptors of the retina

Question 3

Light is focused by optical components. What are the optical components (3)

Answer 3

1. ) Cornea
2. ) Lens
3. ) Ocular media

Question 4

the optical components focus light onto the retinal surface where what then happens?

Answer 4

Photoreceptors transform the light energy into electrical signals, which are transmitted along visual pathways to the cortex

Question 5

What produces one’s “blind spot” and serves as the exit of the optic nerve?

Answer 5

Optic Disk

Question 6

Macula lutea contains what?

Answer 6

Central fovea (pit)

Question 7

How many cell layers are their of the retina? Name them?

Answer 7

1. ) Pigment cell layer
2. ) Rods
3. ) Cones
4. ) Ganglion cell layer

Question 8

Rods are located where, and detect what?

Answer 8

Periphery of the retina

—low light vision & perception of movement

Question 9

Cones are located where and detect what?

Answer 9

Central retina

–Foeva (only cones) is the area of maximum visual activity, color, and brightness discrimination

Question 10

Name the role/characteristics of the Pigment Cell Layer

Answer 10

1. ) Derived from choroid
2. ) Attaches retina to eyeball
3. ) absorbs stray light

Question 11

Myelinated axons of what retina cellular layer form the optic nerve

Answer 11

Ganglion Cell Layer

Question 12

During refraction, in the normal eye a ______ image of the object is focused on the retina

Answer 12

Inverted

Question 13

Light is refracted by what 4 components?

Answer 13

1. )Cornea
2. ) Aqueous humor
3. ) Lens
4. ) Vitreous Humor

Question 14

What is the function of the Lens?

Answer 14

Changes the refractive power by changing the shape of the lens.

• –Rounder/Convex for close viewing
• –Flatter for distant viewing

Question 15

Change in refractive power to allow for viewing of near objects is called what?

Answer 15

Accommodation

Question 16

At rest the lens is held in a relatively flat shape by what?

Answer 16

Suspensory fibers that connect it to the ciliary muscle

Question 17

In regards to the ciliary muscle, to accommodate for near version what must happen?

Answer 17

The Ciliary muscle contracts, reducing the tension on the suspensory fiber
—due to lens natural elasticity, it contracts into a more spherical shape

Question 18

Contraction of the Ciliary muscles is controlled by what?

Answer 18

Parasympathetic nerve fibers

Question 19

What is Emmetropia?

Answer 19

A normally occurring condition where the image of an object is focused on the retinal surface

Question 20

What is Hypermetropia?

Answer 20

Far-sightedness

—The focal point falls behind the retinal surface

Question 21

What is Myopia?

Answer 21

Near-sightedness

—The focal point falls in front of the retina

Question 22

What is Presbyopia?

Answer 22

Los of lens elasticity noted with age