Lectures 8-9 Senses Flashcards

1
Q

Draw and label the different parts of the eye

A

Parts:
- iris
- lens
- vitreous fluid
- retina
- fovea
- pupil
- optic nerve
- cornea
- anterior chamber

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2
Q

Draw and label the different parts of the ear

A

Outer:
- Pinna (ear)
- auditory canal
Middle:
- ossicles (bones)
–> malleus (hammer)
–> incus (anvil)
–> stapes (stirrup)
- muscles
–> tensor tympani
–> stapedius
Inner:
- cochlea

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3
Q

Sensation definition

A

Stimulation of our sense organs and the relay of that information to the brain (transduction)

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4
Q

Perception definition

A
  • the brain’s interpretation of the stimuli in a way that is meaningful to you
  • how the brain groups sensory stimulation into meaningful images
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5
Q

Absolute threshold? Universal?

A
  • minimum amount of stimulus necessary to produce a sensory experience in 50% of cases
  • not universal
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6
Q

Where does auditory sensation become a neural stimulus? How does it happen?

A

In the inner ear
1. Vibrations from the outer and middle ear move fluid in the inner ear
2. Fluid in cochlea moves hair cells (cilia)
3. Movement of cilia opens K+ channels
–> mechanical-gated channels
–> tense the rope, channel opens
–> let it go, channel closes
4. Cell depolarizes
–> K+ goes in, becomes more positive
–> Ca+ channels open
–> Release NTs
5. Electrical impulses and NTs hit the auditory nerve

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7
Q

Auditory pathway?

A
  1. hair cells in cochlea
  2. auditory nerve
  3. cochlear nucleus in brainstem (medulla oblongata)
  4. superior olivary nucleus (pons)
  5. inferior colliculus (midbrain)
  6. medial geniculate nucleus (thalamus)
  7. primary auditory cortex
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8
Q

Types of deafness?

A
  1. Conduction
  2. Sensorineural
  3. Central
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9
Q

Conduction deafness?

A
  • problems in outer and middle ear
  • auditory stimulus doesn’t reach cochlea
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10
Q

Sensorineural deafness?

A
  • auditory nerve fibers are unable to become excited
  • action potentials are not created
  • can be caused by…
    –> antibiotics
    –> loud music/sound (cilia break or die)
  • you have to lose about 40% to actually have reduced hearing
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11
Q

Central deafness?

A
  • brain lesion in auditory cortex
  • sensation cannot become perception
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12
Q

What happens if hair cells die?

A

You start to lose hearing. Hair cells are responsible for changing sensation into neural activity by releasing NTs. If they die, they can’t be regenerated. So, you start to lose hearing.

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13
Q

What type of deafness is more likely to happen because of loud noises? Explain your
answer

A
  • sensorineural deafness
  • loud noises make hair cells break/die
  • if hair cells don’t work, the connection from sensation to neural activity doesn’t happen
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14
Q

When people lose an ear, their ability to hear is impaired. Based on what we discussed
in class, what causes the hearing deficit in these cases?

A
  • the outer ear is designed to help with the reception of sounds that are frequencies we can hear
  • without it, we don’t get all the sound that we could be getting
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15
Q

What is the function of the ossicles in the middle ear?

A
  • Inner ear is filled with fluid that is more dense than air
  • The bones increase the vibrations
  • They are set into motion by the tympanic membrane.
  • They hit one another to increase the strength of the message when it gets to the cochlea
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16
Q

When we come out of a dark place to an illuminated place, it takes some time for our
eyes to see again. Explain the biological reason for this phenomenon

A

when you’re in a dark place, your pupils are open all the way to get in as much light as possible so you can see
When you walk into a bright place, it is too bright for your eyes to see, so you have to wait for your pupils to get smaller so you can see well again

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17
Q

What are photoreceptors?

A

Cones and rods

18
Q

Cones?

A

Very receptive to light
responsible for seeing in color
most cones are in the fovea
around 6 million cones

19
Q

rods?

A

most sensitive when its darker
around 120 million rods
all around the retina
important for peripheral vision

20
Q

What is the fovea?

A

It is a part of the retina
distinguished because it has so many receptors
full of cones

21
Q

Retina? 3 types of cells?

A
  1. photoreceptors (rods and cones)
  2. bipolar cells
    –> travels from photoreceptors to ganglion cells)
  3. ganglion cells
    –> gather together to form the optic nerve
22
Q

Why is the lens flexible? What happens when it’s not?

A
  • The lens changes shape to help you focus on images that are close up (and/or far away)
  • When it becomes less elastic / hardens, you can’t focus on things closer up
  • Hardens as you age
  • Why adults need reading glasses
23
Q

Visual pathway? (6 steps)

A
  1. cones/rods
  2. optic nerve
  3. optic chiasm
  4. optic tract
  5. thalamus (lateral geniculate nuclei)
  6. primary visual areas of the occipital lobes

(10% goes to the superior colliculus, responsible for moving your eyes)

24
Q

Trichomatic theory of color

A
  • Young and Helmholtz
  • 3 types of cone receptors (red, green, blue)
  • doesn’t explain color blindness, as you’re often blind to 2+ colors, not just one
25
Q

Opponent-process theory? Who?

A
  • Hering
  • cone receptors are linked together, forming 3 opposing color pairs
  • red-green
  • yellow-blue
  • black-white
26
Q

Phi phenomenon definition? Give an example.

A
  • perception of movement in the absence of movement
  • Wertheimer
  • ex. old fashioned movie projectors are individual images moving really fast, so we see them as consistent movement
27
Q

What are the principles of perceptual organization?

A
  1. law of figure-ground
  2. laws of grouping
    a. proximity
    b. similarity
    c. closure
    d. continuity
  3. law of good continuation
28
Q

Law of figure-ground? Ex.?

A
  • your brain decides what is the figure and what is the background, and decides what to see
    Ex:
  • images where it asks you ‘what did you see first’
  • tree vs. gorilla and lion
  • W / N example from notes
29
Q

Law of good continuity

A
  • brain follows the simplest possible pattern/path
    Ex.
  • 2 squigly lines that cross each other are perceived as ↜ and ↝ not > and < (where they stop in the middle and reverse)
30
Q

Law of proximity

A

You group objects that are closer together as one object
Ex.
|||| vs || ||
1 group vs 2 groups

31
Q

Law of similarity

A

group things that are similar together, things that are different apart
ex.
triangle of triangles within square of circles

32
Q

Law of closure

A

if there are gaps, your brain fills in the gaps
ex. IBM logo where there’s lines of white space through the letters

33
Q

Law of good continuation

A
  • similar to law of closure
  • you continue ‘lines’ or things even though you can’t see them
    Ex.
    arrow through a heart
    olympic rings
34
Q

What does it mean that we have perceptual constancy of shape and size? Definition?

A
  • even though image we see changes, we still perceive it as the same object
    (we know that objects are unchanging even as illumination and retinal/perceptual images change)
  • things seem big when close and small when far away, but it doesn’t change the size of the object
  • you can see a door on an angle / perspective
  • important
35
Q

Depth perception cues?

A
  • retinal disparity
  • relative size
  • interposition
  • relative clarity
  • texture gradient
  • linear perspective
36
Q

Retinal disparity

A

Your eyes don’t see exactly the same
if you see slightly different, the object is close

37
Q

Relative size

A

You know the size of the object. If it seems bigger, its closer. If it seems smaller, its farther

38
Q

Interposition

A

The partially covered object is farther away than the one you see completely

39
Q

relative clarity

A

the more clear the object is, the closer it is to you

40
Q

texture gradient

A

the more texture you can see, the closer the object is to you

41
Q

linear perspective

A

if you see lines, and the lines are getting closer, you perceive that it is getting further away

42
Q

Retina? 3 types of cells?

A
  1. photoreceptors (rods and cones)
  2. bipolar cells
    (travels from photoreceptors to ganglion cells)
  3. ganglion cells
    –> gather together to form the optic nerve