Sensation And Perception: Ch. 2 The First Steps In Vison

Front 1

Wave

Back 1

an oscillation that travels through a medium by transferring energy from one particle or point to another without causing any permanent displacement of the medium.

Front 2

Photon

Back 2

a quantum of visible light or other form of electromagnetic radiation demonstrating both particle and wave properties.

Front 3

Absorb

Back 3

to take up light, noise, or energy and not transmit it at all.

Front 4

Diffraction

Back 4

the bending or spreading out of waves--for example, of sound or light--as they pass around the edge of an obstacle or through a narrow aperture.

Front 5

Reflect

Back 5

to redirect something that strikes a surface, especially light, sound, or heat, usually back toward its point of origin.

Front 6

Transmit

Back 6

to pass something (e.g. light) on.

Front 7

Refract

Back 7

1. to alter the course of a wave of energy that passes into something from another medium, as water does to light entering it from the air. 2. to measure the degree of refraction in a lens or eye.

Front 8

Image

Back 8

a picture or likeness.

Front 9

Cornea

Back 9

the transparent "window" into the eyeball.

Front 10

Transparent

Back 10

allowing light to pass through with no interruption so that objects on the other side can be clearly seen.

Front 11

Aqueous humor

Back 11

the water fluid in the anterior chamber.

Front 12

Crystalline lens

Back 12

the lens inside the eye which enables changing focus.

Front 13

Pupil

Back 13

the dark circular opening at the center of the iris in the eye, where light enters the eye.

Front 14

Iris

Back 14

the colored part of the eye, consisting of a muscular diaphragm surrounding the pupil and regulating the light entering the eye by expanding and contracting the pupil.

Front 15

Vitreous humor

Back 15

the transparent fluid that fills the vitreous chamber in the posterior part of the eye.

Front 16

Retina

Back 16

a light-sensitive membrane in the back of the eye that contains rods and cones, which receive an image from the lens and send it to the brain through the optic nerve.

Front 17

Accomodation

Back 17

the process by which the eye changes its focus (in which the lens gets fatter as you direct your gaze toward nearer objects).

Front 18

Emmetropia

Back 18

the happy condition of no refractive error.

Front 19

Myopia

Back 19

a common condition in which light entering the eye is focused in front of the retina and distant objects cannot be seen sharply.

Front 20

Hyperopia

Back 20

a common condition in which light entering the eye is focused behind the retina.

Front 21

Astigmatism

Back 21

a visual defect caused by the unequal curving of one or more of the refractive surfaces of the eye, usually the cornea.

Front 22

Transduced

Back 22

refers to the conversion from one form of energy (e.g., light) to another (e.g., electricity)

Front 23

Fundus

Back 23

the eye doctor's view of the retina and optic nerve.

Front 24

Photoreceptor

Back 24

light sensitive receptors in the retina.

Front 25

Rods

Back 25

photoreceptors that are specialized for night vision.

Front 26

Cones

Back 26

photoreceptors that are specialized for daylight vision, fine visual acuity and color.

Front 27

Duplex

Back 27

referring to the retina, meaning that it consists of two parts: the rods and cones, which operate under different conditions.

Front 28

Outer segment

Back 28

part of a photoreceptor which contains photopigment molecules.

Front 29

Inner segment

Back 29

part of the photoreceptor that lies between the outer segment and the cell nucleus.

Front 30

Synaptic terminal

Back 30

the location where axons terminate at the synapse for transmission of information by release of a chemical transmitter.

Front 31

Chromophore

Back 31

the light-catching part of the visual pigments of the retina.

Front 32

Rhodopsin

Back 32

the visual pigment found in rods.

Front 33

Photoactivation

Back 33

activation by light

Front 34

Hyperpolarization

Back 34

an increase in membrane potential where the inner membrane surface becomes more negative that the outer membrane surface.

Front 35

Graded potential

Back 35

an electrical potential that can vary continuously in amplitude.

Front 36

Eccentricity

Back 36

referring to the distance between the retinal image and the fovea.

Front 37

Horizontal cells

Back 37

specialized retinal cells that contact both photoreceptor and bipolar cells.

Front 38

Lateral inhibition

Back 38

antagonistic neural interaction between adjacent regions of the retina.

Front 39

Amacrine cells

Back 39

retinal cells found in the inner synaptic layer which make synaptic contacts with bipolar cells, ganglion cells, and one another.

Front 40

Diffuse bipolar cells

Back 40

bipolar retinal cells whose processes are spread out to receive input from multiple cones.

Front 41

Midget bipolar cells

Back 41

Small cone bipolar cells in the central retina that receive input from a single cone.

Front 42

Sensitive

Back 42

1. able to perceive via the sense organs. 2. extremely responsive to radiation, especially to light of a specific wavelength. 3. able to respond to transmitted signals.

Front 43

Visual acuity

Back 43

a measure of the finest detail that one can resolve.

Front 44

ON midget bipolar

Back 44

a small cone bipolar cell that depolarizes in response to an increase in light intensity.

Front 45

OFF midget bipolar

Back 45

a small cone bipolar cell that depolarizes in response to a decrease in light intensity.

Front 46

Midget ganglion cells

Back 46

small ganglion cells that receive excitatory input from single midget bipolar cells in the central retina.

Front 47

Parasol ganglion cells

Back 47

a unistratisfied ganglion cell that looks like an umbrella, and receives input from diffuse bipolar cells.

Front 48

Receptive field

Back 48

the region in space in which stimuli will activate a neuron.

Front 49

ON-center cell

Back 49

a cell that depolarizes in response to an increase in light intensity in its receptive field center.

Front 50

OFF-center cell

Back 50

a cell that depolarizes in response to a decrease in light intensity in its receptive field center.

Front 51

Contrast

Back 51

the difference in luminance between an object and the back ground or between lighter and darker pars of the same object.

Front 52

Filter

Back 52

an acoustic, electrical, electronic, or optical device, instrument, computer program, or neuron that allows the passage of some frequencies or digital elements and blocks the passage of others.

Front 53

Retinitis pigmentosa (RP)

Back 53

a progressive degeneration of the retina that affects night vision and peripheral vision. Retinitis pigmentosa commonly runs in families and can be caused by defects in a number of different genes that have recently been identified.