Chapter 3

Question 1

Electromagnetic energy

Answer 1

Energy that includes light that is simultaneously both a wave and a particle

Question 2

Wavelength

Answer 2

The distance between two adjacent peaks in a repeating wave; different forms of electromagnetic energy are classified by their wavelengths

Question 3

Intensity

Answer 3

When referring to waves, the height of the wave

Question 4

Frequency

Answer 4

The number of waves per unit of time; frequency is the inverse of wavelength

Question 5

Electromagnetic spectrum

Answer 5

the complete range of wavelengths of light and other electromagnetic energy

Question 6

Photon

Answer 6

A single particle of light

Question 7

Field of view

Answer 7

The part of the world you can see without eye movements

Question 8

Cornea

Answer 8

The clear front surface of the eye that allows light in; it also is a major focusing element of the eye

Question 9

Sclera

Answer 9

The outside surface of the eye; it is a protective membrane covering the eye that gives the eye its characteristic white appearance

Question 10

Anterior chamber

Answer 10

The fluid filled space between the cornea and the iris

Question 11

Iris

Answer 11

The colored part of the eye; it is really a muscle that controls the amount of light entering through the pupil

Question 12

Pupil

Answer 12

An opening in the middle of the iris

Question 13

Pupillary reflex

Answer 13

When the iris reacts to the amount of light; the reflex controls the size of the pupil

Question 14

Heterochromia

Answer 14

A condition in which a person has irises of two different colors

Question 15

Posterior chamber

Answer 15

The space between the iris and the lens; it is also filled with fluid, known as aqueous humor

Question 16

Lens

Answer 16

The adjustable focusing element of the eye, located right behind the iris or the eye; also called the crystalline lens

Question 17

Accommodation

Answer 17

The process of adjusting the lens of the eye so that both near and far objects can be seen clearly

Question 18

Ciliary muscles

Answer 18

The small muscles that change the curvature of the lens, allowing accommodation

Question 19

Zonule fibers

Answer 19

Fibers that connect the lens to the choroid membrane

Question 20

Rods

Answer 20

Photoreceptors at the periphery of the retina; they are very light sensitive and specialized for night vision

Question 21

Cones

Answer 21

Photoreceptors in the fovea of the retina; they are responsible for color vision and our high visual acuity

Question 22

Fovea

Answer 22

An area on the retina that is dense in cones but lacks rods; when we look directly at an object, it’s image falls on the fovea (also referred to as the macula)

Question 23

Macula

Answer 23

The center of the retina; the macula includes the fovea but is larger than it

Question 24

Optic disc

Answer 24

The part of the retina where the optic nerve leaves the eye and heads to the brain; along the optic disc, there are no receptor cells

Question 25

Photopigment

Answer 25

A molecule that absorbs light and by doing so releases an electronic potential by altering the voltage in the cell

Question 26

Opsin

Answer 26

The protein portion of a photopigment that captures the photon of light and begins the process of transduction; it is the variation in opsin that determines the type of visual receptor

Question 27

Retinal

Answer 27

A derivative of vitamin A that is part of a photopigment

Question 28

Hyper-polarization

Answer 28

A change in the voltage of a neuron whereby the inside of the cell becomes more negative than it is in its resting state