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Sensory Processses > Chapter 2: The beginning of perceptual processes > Flashcards

Chapter 2: The beginning of perceptual processes Flashcards

1
Q

Accommodation

A

the change in the lens’s shape that occurs when the ciliary muscles at the front of the eye tighten and increase the curvature of the lense so that it gets thicker

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2
Q

blind spot

A

area of the eye with no receptors, where the optic nerve leaves the eye

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3
Q

cones

A

found in the fovea, a type of visual receptor

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4
Q

cornea

A

focuses light in the eye, transparent covering of the front of the eyes accoutns for about 80 of the eyes focusing power, but it is fixed in place and cannot adjust

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5
Q

eyes

A

contains the receptors for vision (earliest eyes were eyespots that could distinguish between light and dark)

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6
Q

fovea

A

one small area that contains ONLY cones, and when we look directly at an object, the object’s image falls into the fovea

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7
Q

lens

A

focuses light in the eye, 20% of the focusing power, but can change its shape to adjust the eye’s focus for objects located at different distances

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8
Q

macular degeneration

A

when the fovea is destroyed and the small area around it, which creates a blind region in the central vision, so when someone looks directly at something they loose sight of it

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9
Q

optic nerve

A

signals go through the back of the eye through this, it contains a million optic nerve fibers that conduct signals toward the brain

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10
Q

outer segments

A

the part of the receptor that contains light sensitive chemicals called visual pigments that react to light and trigger elec signals

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11
Q

peripheral retina

A

all the retina outside the fovea, with both rods and cones, more rods than cones, about 120M R to 6M C

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12
Q

pupil

A

where light enters through the eye

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13
Q

retina

A

the netweokr of neurons that covers the back of the eyes and contains the receptors for vision

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14
Q

retinitis pigmentosa

A

generational condition, attacks the peripheral rod recpetors and results in poor vision in the periphery

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15
Q

rods

A

visual receptor, more common than cones, only found in the periphery

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16
Q

visible light

A

small subset of the electromagnetic spectrum that humans can percieve with wavelengths from 400-700 nm

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17
Q

visual pigments

A

light sensitive chemical that triggers electrical signals

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18
Q

wavelength

A

the distance between the peaks of electromagnetic waves

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19
Q

describe how the cornea and lens focus image on the retina

A

the cornea focuses about 80% of the light but its unmoving, and the lens focuses the other 20% but can change and adjust based on the distance and light that it avaliable

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20
Q

absorption spectrum

A

a plot of the amount of light absorbed versus the wavelength of the light

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21
Q

axial myopia

A

the eyeball is too long, so the image doesnt focuses too far ahead of the retina

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22
Q

cone spectral sensitivity

A

measured y having a subject look directly as a test light so taht it stimulates only the coens in teh fovea

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23
Q

dark adapted sensitivity

A

the sensitivity at the end of dark adaptation is about 100,000 time greated than the light-adapted sensitivity measured before dark adaptation began

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24
Q

dark adaptation curve

A

measures dark adaptation, the function relating sensitivity to light to time in the dark, beginning when theh light are extinguished

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25
Q

dark adaptation

A

the process in which a person starts to see better in the dark after a little while after adjusting

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26
Q

detached retina

A

when the retina becomes deattached from the pigment epithelium, which is required for visual pigment regeneration, makes people blind at that part

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27
Q

farsightedness

A

can see distant objects clearly but have trouble seeing nearby objects because the focus point for parallel raus of light is located behind the retina, usually because the eyeball is too short

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28
Q

hyperopia

A

can see distant objects clearly but have trouble seeing nearby objects because the focus point for parallel raus of light is located behind the retina, usually because the eyeball is too short

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29
Q

light-adapted sensitivity

A

1/threshold, sensitivity measured inthe light, mesured while the eyes are adapted to the light

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30
Q

monochromatic light

A

light of a single wavelength, can be measured using a spectrometer

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31
Q

myopia

A

an inability to see distant objects cleary, and affects more than 70 million americans - occurs when the optical ssystem brings parallel rays of light into focus at a point in front of the retina, so the image that reaches the retina is blurred.

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32
Q

nearsightedness

A

an inability to see distant objects cleary, and affects more than 70 million americans - occurs when the optical system brings parallel rays of light into focus at a point in front of the retina, so the image that reaches the retina is blurred.

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33
Q

presbyopia

A

the loss of ability to accomodate enough to see objects or read at a close range (fixed by wearing reading glasses)

34
Q

refractive myopia

A

the cornea/the lens bends the light too much

35
Q

rod spectral sensitivity

A

measured after the eyes is dark apadated (when rods control visio) and presenting test flashes inthe peripheral retina

36
Q

spectral sensitivity curve

A

the relationship between wavelength and sensitivity

37
Q

spectral sensitvity

A

a point of the spectral sensitivity curve

38
Q

visual pigment bleaching

A

the change in shape of the retinal and seperations from the opsin causes the molecule to become lighter in color

39
Q

visual pigment regeneration

A

the process of reforming the visual pigment molecule, because whenth epigments are in their bleached state they are no longer useful for vision

40
Q

describe the role of visual pigments in transduction

A

visual pigments are important to seeing, and the convert the light energy into electrical energy via transduction

41
Q

describe the method for measuring dark adaptation and the overall results

A

dark adaptatation is better for the cones than rods

42
Q

discuss the difference between the distributions of the rods and the cones

A

rods are inthe periphery, cones are very concentrated in the fovea and also dispered throughout the erphery but muchhhh less than rods

43
Q

explain why the “blind spot” exists and why we are not usually aware of it

A

it occurs because that is where the optic nerve leaves the eye, and we are usually unaware of it because out brain tried to fill it in

44
Q

action potential

A

axon rises 40mV and then decreases again, lasts about 1millisecond, remains the same size no matter how intense the stimulus is

45
Q

axon

A

filled with fluid that conducts electrical signals

46
Q

cell body

A

contains mechanisms to keep the neuron alive

47
Q

dendrites

A

branch out from the cellbody to recive eelctrical signals from other neurons

48
Q

depolarization

A

when the inside of the neuron becomes more postive
(excitatory response)

49
Q

excitatory response

A

when the inside of the neuron becomes more postive (depolarization), increases neuron firing

50
Q

falling phase of the action potential

A

potassium rushes out of the axon which causes the axon to become more negative (+40mV back to -70mV)

51
Q

hyperpolerization

A

the inside of the neuron becomes more negative (inhibitory response)

52
Q

inhibitory response

A

the inside of the neuron becomes more negative (hyperpolarization) decreases nerve firing

53
Q

ions

A

molecules that carry an electrical charge

54
Q

isomerization

A

when the visual pifment molecule absorbs light and the retinal changes its shape from bent to stract which creates a chemical reaction that activates thousands of charged moleciles to create electrical signals in receptors

55
Q

nerve fiber

A

filled with fluid that conducts electrical signals (also an axon)

56
Q

neurons

A

where electrical signals occur

57
Q

neurotransmitters

A

small chemicals stored in synaptic vesicles in the sending neuron that flow into the synapse to small areas on the recieving neurons

58
Q

permeability

A

the ease in with which a molecule can pass through the mebrane, in reerence to teh sodium channels when an action potential travels through the axon

59
Q

propagated response

A

one the response it trigger, it travels all the way down the axon without decreasing in size ( enables signals to go across long distances)

60
Q

receptor sites

A

areas on the neuron that are sensitive to specifi neurotransmitters

61
Q

refractory period

A

the interval between the time one nerve impulse occurs and the next one cam be generated in the axon (about 1 ms) so the upper rate of firing is about 500-800 impulses per second

62
Q

rising phase of the action potential

A

the increase in potential from -70mV to +40mV (sodium rushes in)

63
Q

resting potential

A

-70 mV, no signals outside the neuron

64
Q

spontaneous activity

A

action potentials that occur in the absense of stimuli from the enviornment

65
Q

synapse

A

the small space between neurons

66
Q

transduction

A

visual transduction occurs int he rods and cones which transform light into electricity using visual pigments

67
Q

identify the key components of neurons

A

cellbody, axon, dendrites, synapse

68
Q

define propagated response and discuss how this is related to measuring activity in a single neuron

A

once a signal is released it travels down the neuron without decreasing in size, which means that it can travel long distances. also it means that the speed of firing doesnt change but the RATE of firing varies

69
Q

describe depolarization, hyperpolarization, and inhibition

A

depolatization is a exitatory reponse that means there is more positive in the neuron, verus hyperpolizaiton which is an inhibitory response which is more negative in the neuron

70
Q

amacrine cells

A

allows signals ot travel between bipolar and ganglion cells

71
Q

bipolar cells

A

right after the receptors

72
Q

convergence

A

multiple signals going to one cell, happens alot with ganglion cells in the eye

73
Q

ganglion cells

A

right after bipolar cells, have long axons like neurons, which transmit signals out of he retina in the optic nerve

74
Q

horizontal cells

A

allows signals to travel between receptors

75
Q

neural circuits

A

interconnected groups of neurons within the retina

76
Q

neural convergence

A

happens when a number ofneurons synapse onto a signle neuron (happens opften in the retina)

77
Q

visual acuity

A

refers to the ability to see details, like being able to see very small letters on an eye, increases in cones

78
Q

visual evoked potential

A

electrical response that is generated by the visual cortex that occures when the stimukus is large enought to be detected by the visual system (used for babies)

79
Q

describe what convergence is, and how it related to acuity in rods and cones

A

cones have higher acuity while rods have higher sensistivity

80
Q

rod-cone break

A

the place where the rods begin to determine the dark adaptation curve (20-30 minutes)

Sensory Processses (8 decks)

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