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Psych 303 - Exam One > Chapter Two > Flashcards

Chapter Two Flashcards

1
Q
  • What is vision based on?
A

Vision - based on visible light (light energy or photons)

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2
Q

Electromagnetic Spectrum

A

Electromagnetic Spectrum

  • Electric energy sent on waves
  • electrical energy spreading microscopic waves
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3
Q

Wavelengths

A

Wavelengths - distance between the peaks of electromagnetic waves

  • humans perceive 400 - 700 nanometers (nm) - our visible light
  • Short wavelength = blue
  • Middle wavelength = green
  • Long wavelength = yellow, orange, red
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4
Q

Visible light

A

Visible light - humans perceive 400 - 700 nanometers (nm)

  • Short wavelength = blue
  • Middle wavelength = green
  • Long wavelength = yellow, orange, red
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5
Q
  • Know the structure of the eye: pupil, cornea, lens, ciliary muscles, retina, and optic nerve. (pp. 22-23)
A

Structure of the Eye:
Pupil- an opening for light to enter
Cornea - nonadjustable clear part covering the front; 80% of where images are focused
Lens - adjustable to deal with distance; 20% of where images are focused
Ciliary muscles- help shape the lens to focus on far and close objects
Retina - back of eye containing rods and cones
Optic Nerve - sends electrical signals to the brain

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6
Q

Pupil

A

Pupil- an opening for light to enter

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7
Q

Cornea

A

Cornea - nonadjustable clear part covering the front; 80% of where images are focused

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8
Q

Lens

A

Lens - adjustable to deal with distance; 20% of where images are focused

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9
Q

Ciliary muscles

A

Ciliary muscles- help shape the lens to focus on far and close objects

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10
Q

Retina

A

Retina - back of eye containing rods and cones

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11
Q

Optic Nerve

A

Optic Nerve - sends electrical signals to the brain

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12
Q
  • What are rods and cones?
A

Rods and cones contain light-sensitive chemicals called visual pigments
Rods - Large, cylinder shape, depth and shape
Cones - small, cone-like, color and detail

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13
Q

Visual Pigments

A

Visual Pigments - react to light and create electrical signals to the optic nerve

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14
Q
  • Know the two transformations operated in the retina to see. (pp. 23)
A

2 Transformations:

  1. Light from object turns into image
  2. Image turns into electrical signal in the brain
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15
Q
  • What is accommodation? (pp. 24)
A

Accommodation
- unconscious adjustment of the len’s shape to focus image

  • ciliary muscles tighten -thicker curvature of the lens
    +bends light rays in lens to reach the retina for sharper image
    +focus on near objects
  • ciliary muscles relax - thinner curvature of lens
    +focus on far objects
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16
Q
  • What is the difference between near point (pp. 24) and far point (pp. 25)?
A

Accommodation has its limits - image becomes blurry when it is no longer close to your near or far points

Near Point - the point at which a close object can be seen clearly without being blurry

Far point - the point at which a far object can be seen clearly without being blurry

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17
Q

Presbyopia

A

Presbyopia - “old eye”

  • distance of near point increases with age
  • lens harden and ciliary muscles weaken
  • corrective lenses (glasses) are needed
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18
Q

Myopia

A

Myopia (nearsightedness)

  • close objects = clear
  • far objects = blurry

Two possible problems for Myopia:
1. Refractive myopia = cornea and/or lens bend too much light
2. Axial myopia = eyeball is long
-Both problems do not reach retina properly
+farpoint reaches in front of the retina

19
Q

Hyperopia (pp. 24-26)

A

Hyperopia (farsightedness)

  • close objects = blurry
  • far objects = clear
  • near point reaches behind the retina
    +eyeball is too short
20
Q

What is transduction?

A

Transduction - change from environmental energy to electrical energy in the brain

21
Q

What are the two parts of the visual pigment molecule? Where are they located? (pp. 26-27)

A

Visual Pigment Molecules - contains millions of light-sensitive chemicals to create electric energy
-absorbs light energy (photons) to see

LOCATED IN THE RETINA (RODS AND CONES

in the outer segment of the rods and cones of the retina

Molecules - a group of atoms stuck together; microscopic
Contains 2 parts:
-Opsin - long protein
-Retinal - light sensitive; smaller molecule attached to the opsin

22
Q
  • What is isomerization? (pp. 27)
A

Isomerization - Change of molecule’s shape
-retinal bends straight on the opsin

This change triggers a chemical chain reaction

  • activates a million other visual pigment molecules
  • generates electrical energy in the rods & cones
23
Q
  • Where are the rods and cones located? (pp. 28)
A

Distribution on the retina
Fovea - smaller area, containing only cones; 50,000 cones
Peripheral - outside of fovea, contains more rods than cones; 120 million rods/ 6 million cones

24
Q

macular degeneration (pp. 28),

A

common in older people, destroys the cone rich fovea and a small area that surrounds it. tis creates a blind region in central vision, so when a person looks directionally at something, he or she loses sight of it.

25
Q

retinitis pigmentosa (pp. 29)

A

Degeneration of the retina that is passed from one generation to the next. attacks peripheral visual field

26
Q
  • What and where is the blind spot? (pp. 28-29)
A

Blindspot - absence of the retina (visual receptor)

Located near the optic nerve where electrical signals go to the brain

27
Q

Know the three adaptation curves. What are they? (pp. 29-31)

A

3 Adaptation Curves

  1. Cones - 3-5 minutes to level off, reach maximum sensitivity
  2. Rods - higher sensitivity to dark; 20 - 30 minutes to level off, reach maximum sensitivity
  3. Rod- cone break - when cones cannot adapt any longer; the rods continue to adapt.
28
Q

What is visual pigment regeneration?

A

Visual Pigment Regeneration

  • Pigment regeneration responsible for sensitivity in the dar
  • Retinal need to reattach to opsin
  • Cone pigments - 6 minutes to regenerate
  • Rod pigments - more than 30 minutes
29
Q

What is visual pigment bleaching? (pp. 31-32)

A

Visual Pigment Bleaching

  • Molecule: retinal breaks apart from opsin
  • Bleaching: pigment (color) becomes lighter
  • Not useful for vision when bleached - you cannot see
  • i.e. walking from a dark room to the sun outside
30
Q

2 important relationships between perception and physiology (NOT ON STUDY GUIDE)

A

2 important relationships between perception and physiology

  1. Sensitivity to light depends on visual pigments
  2. Speed of sensitivity depends on chemical reaction (regeneration)
31
Q
  • Understand the cone and rod spectral sensitivity curves. (pp. 32-34)
A

Spectral Sensitivity Curves -To sense color from wavelengths in rods and cones

  • Spectrometer - device to see monochromatic light
  • Rods - more sensitive to / in the dark
  • Cones - more sensitive to / in the light
32
Q
  • Know the structure of a neuron: cell body, dendrites, and axon (also known as nerve fiber) (pp. 35)
A

See picture

33
Q
  • Know the pathways of the visual system from the eye to the striate cortex (pp. 35)
A

Retina –> Optic Nerve –> Lateral Geniculate Nucleus (thalamus)
–> Primary Visual Cortex

34
Q
  • When do electrical signals of a neuron happen? Know the milliVolts (mV) of the resting potential and action potential. What are the basic properties of action potentials (i.e., propagated response, refractory period, and spontaneous activity)? (pp. 36-38)
A

Action potential jump to +40mv, resting -70mv

Propagated response

Refractory period

Spontaneous activity

35
Q
  • How do chemicals affect the electric signal of a neuron (i.e., an action potential, Na+ ions, K+ ions)? (pp. 38-40)
A 
K+ = potassium 
Na+  = sodium - inside axon

DOUBLE CHECK WHAT DOES WHAT

Sending electrical signals
chemical substance (neurotransmitters) - lets other neurons know whether to fire or not - relies on electrical signal to transmit

• Axons contain ions (electrically charged molecules) in & outside of membrane
• Note: more concentration of negative charged ions inside axon during resting potential
• During action potential:
- Sodium ions (Na+) get inside axon
- Potassium (K+) gets outside
• Sodium (Na+) / Potassium (K+) pump:
- Helps return axon to resting potential

36
Q

synapse

A

synapse - a tiny space between neurons where neurotransmitters send electrochemical info

37
Q

neurotransmitters

A

neurotransmitters - chemicals released in the synapse; determines electrical signal

38
Q

depolarization

A

depolarization - excitatory response, triggers action potentials, more positive ions inside axon

39
Q

hyperpolarization

A

hyperpolarization - inhibitory response, prevents action potentials, more negative ions inside axon

40
Q
  • What are neural circuits?

Where do the electrical signals sent from the visual receptors (rods and cones) go in the retina? (pp. 41)

A

Neural Circuits - a group of interconnected neurons

Travel to the bipolar cells and then to the ganglion cells.

41
Q
  • Know how neural convergence and non-convergence affect the sensitivity and acuity for rods and cones (pp. 40-44
A

Neural Convergence - where MULTIPLE neurons synapse onto a SINGLE neuron (quantity)

Non-neural Convergence - where a SINGLE neuron synapse onto another SINGLE neuron (quality)

visual receptors (rods) have more convergence

42
Q

sensitivity

A

sensitivity - ability to process light

43
Q

acuity

A

acuity - ability to process details

44
Q

Convergence in rods and cones

A

Rods- more convergence; high sensitivity; poor acuity

Cones- lack of convergence; low sensitivity, greater acuity

Psych 303 - Exam One (5 decks)

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