somatosensory Flashcards

chapter 13

1
Q

the body senses

A
  1. touch
  2. thermoception
  3. nociception
  4. proprioception / kinaesthesis
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2
Q

tactile perception

A

perception that results fro, the mechanical deformation of the skin

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3
Q

how are tactile receptors classified

A
  1. the type of stimulation they respond to
  2. the size of their rf
  3. speed of adaptation
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4
Q

where are the tactile receptors located

A

in the dermis and epidermis
- epidermis: the most surface layer

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5
Q

mechanoreceptors

A

respond to mechanical stimulation like pressure vibration and movement

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6
Q

4 types of mechanoreceptors

A
  1. SAI (markelle)
  2. SAII
  3. FAI (Meissner)
  4. FAII (Pacinian)
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7
Q

Type 1 vs type 2 receptors

A

type one have smaller receptive fields which give them higher acuity/spatial resolution
- type 1 are usually closer to the surface

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8
Q

slow adapting vs fast adapting receptors

A
  • slow adapting will fire continously as they are stimulated
  • fast will fire when they start and end
  • fast has better temporal
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9
Q

SAI

A
  • markelle cells
  • dense in the dermis
  • high spatial acuity and low temporal variation
  • respond to indentation, curves and textures
  • used to perceive pattern , texture and shape
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10
Q

SA II

A
  • big receptive fields
  • low temporal
  • low spatial
  • respond to stretch and hand conformation
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11
Q

FA I

A
  • small rf
  • dense in the upper dermis
  • high spatial resolution
  • high temporal resolution
    -respond to motion and low frequency
  • used for slip and maintaining grip control
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12
Q

FA II

A
  • large rf
  • sparse density in the lower dermis
  • low spatial
  • high temporal
  • high frequency vibrations
  • used for perceiving fine textures through vibrations
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13
Q

C-Tactile mechanoreceptors

A

receptors that are only present in hairy skin which respond to slow, gently pleasnt touch

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14
Q

two point discrimination

A

psychophysics test to asses the spatial resolution (to point theshold) of the skin
- how far a part do two points have to be for us to feel them as 2

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15
Q

temporal resolution of touch

A

we can discriminate touches that are about 5ms apart

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16
Q

Braille

A

SA I are used for this
FA I are kinda good at it too

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17
Q

mechanoreceptors in grip control

A

FA I is very useful in load phase when it is gripping an object to lift it. FA II detect the additional forces after its lifted.

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18
Q

thermoception

A

sense of temperature

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19
Q

themoreceptors

A

we have separate hot ad cold fibers.
they respond when temperature goes below or above baseline
- within the range of 17-43 c

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20
Q

nociception

A

pain thet arises from potential or actual tissue damage due to physical trauma

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21
Q

2 types of nociceptors

A
  1. c-fibers
  2. A-delta
  • 2 kind of fibers makes pain come in 2 waves
22
Q

C-fibers

A

unmeylinated pain receptors that cause a slower reaction

23
Q

a-delta fibers

A

lightly myelinated fibers that have faster responses

24
Q

other types of pain

A
  • hyperaglesia: inflammatory
  • neuropathic
25
Q

proprioception

A

sense of where things are relative to each other in the boy

26
Q

types of proprioceptive organs

A
  1. muscle spindles
  2. golgi tendons
  3. joint receptors
27
Q

muscle spindles

A
  • they sense lenght and change of lenght of the muscle and isometric force in afferent nerves
28
Q

types of muscle spindles

A

type 1: for dynamic muscles
type 2: for stati lenght

29
Q

golgi tendon organs

A

proprioceptor receptor that sense muscle tension
- so our muscle know what its force output is

30
Q

joint receptors

A

used for telling joint when they are reaching their maximum limits in range of motion

31
Q

dermatones

A

areas of skin that are innervated by different levels of the spinal cord

32
Q

spinal cord composition

A
  • grey matter (ell bodies) is on the inside and the whte matter is on the outside.
  • ventral side has motor neurons
  • dorsal has sensory
33
Q

path into the spinal cord

A

sensory afferent neurons enter though the dorsal root, passing through the dorsal root ganglion

34
Q

pathways of senory signal to the brain

A
  1. dorsal column-medial lemniscal pathway
  2. spinothalamic pathway
35
Q

DCML pathway

A

tactile and proprioception signals travel out of the spine and make their first synapse in the medulla where they cross contrallaterally to the VP in the thalamus then to S1

36
Q

spinothalamic pathway

A

signals from pain and thermal receptors synapse in the spinal cord and cross there to the medulla then the thalamus to the S1

37
Q

Primary somatosensory cortex

A

Subregion of the somatosensory cortex which is the first to receive somatosensory signals (in the central gyrus of the parietal lobe)

38
Q

somatotopic map

A

a mapping of the body surface onto the somatosensory cortex, whereby adjacent locations on the cortex receive signals from adjacent locations on the body
- not proportional

39
Q

homunculus

A

a representation of the body if the area of skin was proportional to the size of the cortex that represents that body part

40
Q

Secondary somatosensory cortex

A

subregion of the somatosensory region which receives signals from area s1

41
Q

areas of the S1

A

3a
3b
1
2

42
Q

Area 3a

A

receives proprioceptive signals and discriminative nociceptive signals

43
Q

area 3b

A

receives tactile signals and discriminative nociceptive signals

44
Q

Area 1

A

receives tactile information

45
Q

Area 2

A

recieves proprioceptive signals

46
Q

pathways after S1

A

after s1 the tactile and proprioceptive information split into dorsal and ventral pathways

47
Q

dorsal pathway of touch

A

the where pathway that carries tactile information in planing action.
goes throuhg posterior parietal cortex to premotor cortex

48
Q

ventral pathway of touch

A

the what pathway that carries proprioceptive and tactile signals to help indentifiy object shape and qualities.
- s1 –> s2 –> hippocampus –> prefrontal cortex

49
Q

haptic perception

A

actively using touch to perceive and identify object by their 3d structure and other material propertie
- uses the other somatosensory sense too

50
Q
A