lecture 13 Flashcards

1
Q

somatic senses

A
  • touch
  • temp
  • itch
  • pain
  • proprioception
    —-> goes to primary cortex in parietal lobe where it is perceived
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2
Q

if a signal reaches the cerebral cortex

A

stimulus enters our consciousness

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3
Q

if signal does not reach the cerebral cortex

A
  1. stimulus is processed and a movement is elicited w/ out our conscious awareness (heart rate, digestion)
  2. not strong enough (not aware)
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4
Q

proprioception

A

awareness of where you are in space (you know you’re sitting)

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5
Q

conscious stimulus processing (special senses)

A
  1. vision—> goes to visual cortex in occipital lobe
  2. hearing —> goes to auditory cortex in temporal lobe
  3. smell and taste —> goes to dedicated region between frontal and temporal lobe
  4. equilibrium (balance) —> involves vestibular apparatus in inner ear
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6
Q

sensory receptors

A
  • convert stimulus into intracellular response
  • the may or may not be neurons
    type of receptor:
    1. chemoreceptor
    2. mechanoreceptor
    3. photoreceptor
    4. thermoreceptor
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7
Q

a change in membrane potential of receptor cell

A

receptor potential

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8
Q

when a light photons fall on retina in the eye, rods and cones _________

A

hyperpolarize

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9
Q

when skin is touched, touch receptors _______

A

depolarize

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10
Q

Transduction

A

Stimulus is converted into an intracellular response

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11
Q

Sensory receptors that are neurons

A

Transduction occurs at the receptor end of primary sensory neurons
Example 1: pain and temperature receptors w/ free nerve endings in the dermis of the skin
- unmylinated
- synapse in dorsal region (gray matter) of spinal cord
- slow
Example 2: Pressure (in closed nerve endings)
- mylinated
- synapse in dorsal region (gray matter) in spinal cord
- fast
In response to their stimulus (pain, temperature, pressure) they produce action potentials

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12
Q

Sensory receptors that are not neurons

A
  • Sensory cell is separate from the primary sensory neurons
  • special senses (vision, hearing, taste) receptors are cells that release neurotransmitters onto a partner primary neuron to fire an AP (indirectly)
  • example: inner ear has hair cells that is caused my finger like projections called cilia that respond when their is mechanical energy
  • intracellular response is receptor potential
  • exception is olfactory system (smell)
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13
Q

stimulus modality

A
  • determined by sensory receptor activated and what area in the brain the sensory signal is sent too
    e.g. when photoreceptors are activated you will perceive light because photoreceptor send signals along visual pathways to visual cortex in occipital lobe
    Label line coding: when you activate a certain receptor (photoreceptor) and that info always goes to the same place (visual cortex) then that info will always be perceived as light
    Example: when u press on your eyes “seeing stars” signal from photoreceptors are always perceived as “light” even if they were activated by another stimulus such as mechanical stress
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14
Q

when would you not get 2 point discrimination?

A
  • when all primary neurons converge and synapse onto a single secondary sensory neuron
  • convergence creates large receptive fields
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15
Q

when would you get 2 point discrimination?

A
  • when each primary neuron has a secondary neuron
  • when fewer neurons converge, secondary receptive fields are much smaller
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16
Q

perception threshold

A

minimum stimulus intensity required for activation of all neurons, thus transmission of signal to the brain for perception

17
Q

stimulus location

A
  • the cerebral cortex is highly organized so that specific areas correspond to specific receptive fields
  • somatosensory cortex is organized so that information coming from specific regions of the body always go to the same place in the primary sensory cortex
  • more cortical= more sensitivity (lips, hands, toes) —> to point discrimination
18
Q

Lateral inhibition

A
  • allows you to detect precisely where a stimulus is
  • turns/shuts off neighbouring neurons
19
Q

intensity

A

coded by number of receptors activated and frequency of action potential

20
Q

duration

A
  • coded by duration of action potential trains
  • some receptors can adapt:
    tonic receptors adapt slowly (fire for duration of action potential)
    phasic receptors adapt quickly (fire only when a stimulus changes) —> olfactory neurons
21
Q

Cutaneous

A

receptors in skin
1. Touch (mechanoreceptors)
- pressure, vibration, sound waves
2. Pain and Itch (nociceptors)
3. Temperature (thermoreceptors)