chapter 3 Flashcards
(46 cards)
1
Q
electromagnetic energy
A
form of energy including light
both a wave and a particle
2
Q
wavelength
A
distance between two adjacent peaks in a repeating wave
different forms of electromagnetic energy are classified by their wavelengths
3
Q
intensity
A
- height of a wave
4
Q
frequency
A
- number of waves per unit of time
- frequency is the inverse of wavelength
5
Q
electromagnetic spectrum
A
- complete range of wavelengths of light and other electromagnetic energy
6
Q
photon
A
- single particle of light
7
Q
cornea
A
- clear front surface of the eye
- allows light in
- focusing
8
Q
sclera
A
- outside surface of the eye
- protective membrane covering the eye
- white part
9
Q
anterior chamber
A
- fluid filled space between the cornea and iris
10
Q
iris
A
- colored part of the eye
- muscle, controls the amount of light entering the pupil
11
Q
pupil
A
- opening in the middle of the iris
12
Q
pupillary reflex
A
- automatic process, controls the size of the pupil
- iris contracts/relaxes in response to the amount of light entering the eye
13
Q
posterior chamber
A
- space between the iris and the lens
- filled with aqueous humor
14
Q
lens
A
- adjustable focusing element of the eye
- located behind the iris
15
Q
accommodation
A
- lens adjusting so near and far objects can be seen clearly
16
Q
ciliary muscles
A
- muscles change the curvature of the lens, allowing accomodation
17
Q
zonule fibers
A
- fibers connecting the lens to the choroid membrane
18
Q
near point
A
- closest distance at which an eye can focus
19
Q
retina
A
- paper thin layer of cells at the back of the eye
- where transduction takes place
20
Q
retinal image
A
- light projected onto the retina
21
Q
rods
A
- photoreceptors at the periphery of the retina
- night vision
22
Q
cones
A
- photoreceptors at the fovea of the retina
- color vision, acuity
23
Q
fovea
A
- area on the retina that is dense in cones but lacks rods
- when we look directly at an object, image falls on the fovea
24
Q
macula
A
- center of the reina
- includes the fovea but is larger than it
25
optic disc
- part of the retina where the optic nerve leaves the eye and heads to the brain
- no receptor cells
26
photopigment
- molecule
- absorbs light, releases an electric potential altering the voltage in the cell
27
opsin
- protein portion of a photopigment
- captures the photon of light, begins the process of transduction
28
retinal
- vitamin A, part of a photopigment
29
hyperpolarization
- change in voltage of a neuron
- inside of a cell becomes more negative than its resting state
30
neurotransmitter
- chemical substance neurons release to communicate with other neurons
31
duplex theory of vision
- 2 distinct ways our eyes work
- photopic, cones
- scotopic, rods
32
photopic vision
- cones
- daytime, good acuity in the fovea, color vision
33
scotopic vision
- rods
- night vision, poor acuity, no color, sensitive to light
34
purkinje shift
- short wavelengths brighter in scotopic vision vs photopic vision
35
convergence
- number of photoreceptors that connect to each ganglion cell
- more convergence for rods vs cones
36
dark adaptation
- sensitivity to low light levels is increased
37
light adaptation
- sensitivity is reduced so we can operate in higher light levels
38
receptive field
- region of space to which a particular neuron responds
39
edge detection
- process of distinguishing where one object ends and the next begins
40
center surround receptive field
- center responds opposite to the surround
41
on center receptive field
- retinal ganglion cells increase firing rate when light is presented in the middle
- retinal ganglion cells decrease firing rate when light is presented outside the receptive field
42
off center receptive field
- retinal ganglion cells decrease firing rate when light is presented in the middle
- retinal ganglion cells increase firing rate when light is presented outside the receptive field
43
lateral inhibition
- a neuron's response to a stimulus is inhibited by the excitation of a neighboring neuron
44
astigmatism
- irregluar shape of the lens
- inability to fully accomodate
45
macular degeneration
- disease destroying the fovea and the area around it
46
field of view
- part of the world you can see without eye movements
