Sensory and Motor Systems: Visual System

Question 1

Whether we’re searching for food or scanning the millions of colors displayed by a computer monitor, the process of vision begins with ____.

Answer 1

light

Question 2

the energy we can see, is one form of electromagnetic radiation produced by the sun.

Answer 2

Visible light

Question 3

the distance between successive peaks of waves, is decoded by the visual system either as color or as shades of gray.

Answer 3

Wavelength

Question 4

refers to the height of each wave, which is translated by the visual system as brightness.

Answer 4

Amplitude

Question 5

Individual, indivisible, very small particles that form waves of electromagnetic energy.

Answer 5

Photons

Question 6

can also be described as the movement of tiny, indivisible particles known as photons.

Answer 6

Electromagnetic radiation

Question 7

Electromagnetic radiation can also be described as the movement of tiny, indivisible particles known as ______.

Answer 7

photons

Question 8

Photons always travel at the same speed (the so-called speed of light), but they can ________.

Answer 8

vary in the amount of energy they possess

Question 9

The range of electromagnetic energy visible to humans falls between ________.

Answer 9

400 and 700 nanometers (nm)

Question 10

The ability to retain something rather than reflect or transmit it to another location.

Answer 10

absorption

Question 11

The bending back of light toward its source.

Answer 11

reflection

Question 12

The deflection, or changing of direction, of light at a boundary such as that between air and water.

Answer 12

refraction

Question 13

_____ and _____ determine the colors we see.

Answer 13

Absorption, reflection

Question 14

The color of an object is not some intrinsic characteristic of the object but, rather, the result of the wavelengths of light that are ______ and ________ by the object.

Answer 14

selectively absorbed, reflected

Question 15

clothing keeps us cooler because materials perceived as white or _______ reflect more electromagnetic energy.

Answer 15

Light-colored

Question 16

clothing keeps us warmer because these materials absorb more electromagnetic energy.

Answer 16

Dark-colored

Question 17

Visual System
Line of Defense

Answer 17

Orbit of the skull
Eyelids
Blink
Tears

Question 18

can deflect many blows

Answer 18

Orbit of the skull

Question 19

can be opened and closed either voluntarily or involuntarily.

Answer 19

Eyelids

Question 20

Involuntary closure of the eyelids protects the eye from incoming objects and moistens and cleans the front of the eye.

Answer 20

Blink

Question 21

another feature of the eyes’ protective system, are produced in the lacrimal gland at the outer corner of each eye.

Answer 21

Tears

Question 22

The fluid is composed primarily of _____ and ____ but also contains proteins, glucose, and substances that kill bacteria.

Answer 22

water, salt

Question 23

Tears flush away ____ and ____ and _____ so that the eyelids don’t scratch the surface during blinks.

Answer 23

dust, debris, moisten the eye

Question 24

The “white” outer covering of the eye.

Answer 24

sclera

Question 25

The transparent outer layer of the eye.

Answer 25

cornea

Question 26

The area of the eye located directly behind the cornea, containing aqueous humor.

Answer 26

anterior chamber

Question 27

The fluid located in the anterior chamber that nourishes the cornea and lens.

Answer 27

aqueous humor

Question 28

The opening in the front of the eye controlled by the iris.

Answer 28

Pupil

Question 29

The circular muscle in the front of the eye that controls the opening of the pupil.

Answer 29

Iris

Question 30

The clear structure behind the pupil and iris that focuses light on the retina.

Answer 30

lens

Question 31

The elaborate network of photoreceptors and interneurons at the back of the eye that is responsible for sensing light.

Answer 31

retina

Question 32

Specialized sensory cell in the retina that responds to light.

Answer 32

photoreceptor

Question 33

The fiber pathway formed by the axons of the ganglion cells as they leave the eye.

Answer 33

optic nerve

Question 34

The area in the retina where blood vessels and the optic nerve exit the eye.

Answer 34

optic disk

Question 35

A 6 mm round area in the retina that is not covered by blood vessels and that is specialized for detailed vision.

Answer 35

macula

Question 36

The ability to perceive visual stimuli focused on the macula of the retina.

Answer 36

central vision

Question 37

The ability to perceive visual stimuli that are off to the side while looking straight ahead.

Answer 37

peripheral vision

Question 38

A small pit in the macula specialized for detailed vision.

Answer 38

fovea

Question 39

The pigmented layer of cells supporting the photoreceptors of the retina.

Answer 39

epithelium

Question 40

2 types of Photoreceptors

Answer 40

Rods, Cones

Question 41

A photoreceptor that responds to low levels of light but not to color. Responsible for scotopic vision, or the ability to see in dim light.

Answer 41

Rods

Question 42

A photoreceptor that operates in bright conditions and responds differentially to color. Cones are responsible for photopic vision, or vision in bright light.

Answer 42

Cones

Question 43

is the process of translating a physical stimulus into electrical signals that can be understood and processed by the nervous system.

Answer 43

Transduction

Question 44

is usually defined as the obtaining of information from the environment and the transmission of that information to the brain.

Answer 44

Sensation

Question 45

involves the interpretation, or meaningful analysis, of sensory data.

Answer 45

Perception

Question 46

considered to be the primary colors of light.

Answer 46

Red, Green, and Blue

Question 47

suggests that human color vision is based on our having three (tri) different color photopigments.

Answer 47

Trichromacy theory

Question 48

A theory of human color vision based on three antagonistic color channels: red-green, blue-yellow, and black-white.

Answer 48

opponent process theory

Question 49

(having two cone photopigments) is the most common type of abnormality and results from a missing or abnormal cone pigment. Because genes for the red and green photopigments appear on the X chromosome, this type of dichromacy is sex-linked, Men are about ten times more likely to be colorblind than women

Answer 49

Dichromacy

Question 50

The ability to see in black and white only.

Answer 50

monochromacy

Question 51

A condition characterized by having three cone photopigments that respond to slightly different wavelengths than normal.

Answer 51

anomalous trichromacy

Question 52

people with four different color pigments (Neitz, Kraft, & Neitz, 1998). These individuals match colors in a manner that would be predicted by their having four color pigments rather than three.

Answer 52

tetrachromats

Question 53

describes the fact that an object’s colors do not appear to change even as the light falling on that object changes.

Answer 53

Color constancy

Question 54

Lazy eye, or _____, occurs when one eye cannot focus on objects.

Answer 54

amblyopia

Question 55

result from clouding of the lens of the eye.

Answer 55

Cataracts

Question 56

Difficulty seeing distant objects. Elongation of the eyeball

Answer 56

Myopia (nearsightedness)

Question 57

Difficulty seeing close objects, reading. Shortening of the eyeball.

Answer 57

Hyperopia (farsightedness)

Question 58

A distortion of vision caused by the shape of the cornea.

Answer 58

astigmatism