Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

KNES 251 > Lecture 10-12 - Somatosensory System > Flashcards

Lecture 10-12 - Somatosensory System Flashcards

1
Q

What are muscle spindles?

A

Specialized sensory receptors found in skeletal muscle that provide feedback on muscle stretching to the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is another name for skeletal muscle fibres?

A

Extrafusal muscle fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How are intrafusal and extrafusal muscle fibres organized?

A

they run in parallel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are intrafusal fibres?

A

non-force producing muscle fibres that lengthen and stretch with changes in muscle length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are afferent axons?

A

innervate sensory endings of muscle spindle and send feedback to spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are efferent axons?

A

gamma MNs innervate polar ends (contractile) of intrafusal fibers and send excitatory inputs from the spinal cord

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do sensory endings do in a muscle spindle do?

A

sense length of intrafusal muscle fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Does the middle (central) part of a muscle spindle contract?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the capsule of a muscle spindle?

A

connective tissue surrounding intrafusal fibers and receptors that compose the spindle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are extrafusal fibres?

A

fibres that cause muscle contraction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do gamma motor neuron endings do in a muscle spindle?

A

stimulate intrafusal muscle fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What afferents wrap around all types of intrafusal endings?

A

primary afferents ( group Ia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a primary afferent and the intrafusal fibres it wraps around called?

A

muscle spindle primary ending

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What afferents make ‘flower spray endings’?

A

Secondary (group II)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the secondary afferent and the intrafusal fibres it contacts called?

A

muscle spindle secondary ending

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the two major categories of intrafusal muscle fibres?

A

Bag and chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How are bag intrafusal fibres arranged?

A

nuclei arranged In a central ‘bag’ region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How are chain intrafusal fibres arranged?

A

nuclei arranged along a straight ‘chain’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do mechanically gated ion channels in muscle spindles work?

A

Cytoskeletal strands bind ion channels together so as muscles stretches the strands becomes stiff and pull on the ion channels so they open allowing more Na+ to enter the cell. Larger stretches lead to larger receptor potentials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What does the firing rate of muscle spindles correspond to?

A

Changes in muscle length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What provides the CNS with a sensory input proportional to the length of the muscle?

A

Difference in the firing rate between the initial and final length of the muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What provides the CNS with a sensory input proportional to the velocity of muscle stretch?

A

Difference in firing rate of muscle spindles during the dynamic phase (when the muscle is being stretched) of muscle stretch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What do chain type intrafusal muscle fibres do?

A

Measure muscle length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What do bag type muscle fibres do?

A

Measure the dynamic phase of muscle stretch “velocity of stretch”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What nerve endings are more sensitive to the dynamic phase of movement (velocity of stretch)?

A

Primary endings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What does the firing rate of primary endings during the dynamic phase closely correspond to?

A

the velocity of muscle stretching

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What do higher velocities result in?

A

Larger dynamic responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are secondary endings sensitive to?

A

Muscle length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What type of nerve endings are useful for proprioception?

A

secondary endings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what type of nerve endings are useful for kinesthesia?

A

primary endings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What would happen without Gamma MNs?

A

if the muscle were to contract to a shorter length, the intrafusal fibres would become slack and the spindle would stop providing feedback about where the limbs are

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Why do we have gamma MNs?

A

To make sure that the length of the muscle spindle is the same as the length of the muscle and allows the muscle spindle to keep responding during contractions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is alpha-gamma co-activation?

A

Alpha MNs and Gamma MNs are activated together, they receive the same input so muscles stay the same length. Thought to occur because the same motor commands coming from the cerebral cortex connect both the alpha and gamma MN in the spinal cord.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What do muscle spindles play an integral role in?

A

Proprioception and kinesthesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is prorioception?

A

Our bodies understanding of where it is in space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is kinesthesia

A

our brains understanding of movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is mechanotransduction?

A

Mechanical energy gets converted into a voltage change in sensory afferent neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is another name for EPSP?

A

receptor potential

39
Q

What is a cutaneous receptive feild?

A

region of the skin that is capable of evoking action potentials in a given cutaneous afferent (all cells and part of skin that are innervated by one axon)

40
Q

What is non hairy skin?

A

“glabrous” skin

41
Q

How many types of receptors are located in glabrous skin?

A

4

42
Q

Where are type 1 cutaneous receptors found?

A

Close to surface of skin (superficial)

43
Q

What are the 2 type 1 cutaneous receptors?

A

Meissner and Merkel cell

44
Q

Are merkel cells slow or fast adapting?

A

slow

45
Q

What is the fast adapting type 1 cutaneous receptor?

A

Meissner’s corpuscle

46
Q

What type of cutaneous receptors are Ruffinin endings and pacinian corpuscles?

A

Type 2s (deep)

47
Q

What is the slowly adapting type 2 cutaneous receptor?

A

Ruffini endings

48
Q

Are pacinian corpuscle fast or slow adapting?

A

fast adapting

49
Q

What is the ranking of most (lowest threshold) –> least (highest threshold) sensitive to indentation?

A
  1. Pacinian
  2. Meisner
  3. Merkel
  4. Rufinni
50
Q

Which cutaneous receptor has irregular discharge (uneven spacing between AP’s) when stimulated?

A

Merkel Cells (SA1)

51
Q

Which cutaneous receptors are highly sensitive to edges and curvature?

A

Merkel cells

52
Q

What are ruffini endings very sensitive to?

A

Skin stretch

53
Q

Are ruffini endings found in non-human primates?

A

No

54
Q

Which cutaneous receptor codes for velocity of skin indentation and motion across skin?

A

Meissner corpuscles

55
Q

What is the main cutaneous receptor found in the hand?

A

Meissner corpuscles

56
Q

Are meissner corpuscles sensitive to low or high frequency vibration?

A

Low

57
Q

Do fast adapting cutaneous receptors constantly fire APs?

A

No, they only fire when there is a change in stimulus

58
Q

What do Pacinian corpuscles code for?

A

acceleration (change in indentation rate)

59
Q

What type of frequencies do pacinian receptors pick up?

A

high frequencies

60
Q

Do deep (type 2) receptors have smaller or larger receptive fields?

A

Larger

61
Q

Why do type 1 receptors have smaller receptive fields?

A

they have more than 1 cell attached to a axon

62
Q

Where in the hand are Merkel and Meissner recepetors highly dense?

A

The tip of the finger

63
Q

What type of cutaneous receptors are more evenly distributed in the hand?

A

Pacinian and ruffini

64
Q

What are the functional roles of merkel cells?

A

Edges, curvature and texture

65
Q

What are the functional roles of Meissner corpuscles?

A

slip/motion detection and grip control

66
Q

What is cutaneous receptor is responsible for detecting skin stretch?

A

Ruffini endings

67
Q

What cutaneous receptor is responsible for feeling vibration through objects and perception of fine texture?

A

Pacinian corpuscles

68
Q

What is spatial code?

A

The CNS can determine the location of stimuli based on which afferents specifically are active

69
Q

Which type or cutaneous receptors code for spatial details (size and shape of objects)?

A

SA1’s

70
Q

What happens when you are probed with a small probe?

A

High discharge rate in few afferents

71
Q

What happens when you are probed with larger probe?

A

Individual receptors fire less, but more afferents will be active

72
Q

What is a nociceptor?

A

Pain receptor (is a chemoreceptor)

73
Q

What do nociceptors signal for?

A

Tissue damage

74
Q

If you were to put your hand on hot stove when would the nociceptors become active?

A

Once the heat becomes tissue damaging

75
Q

How do thermally gated receptors work?

A

Heat deforms protein channels allowing it to open

76
Q

T/F: Thermoreceptors are active at lower temperatures than pain receptors

A

true

77
Q

Why are spicy food hot?

A

Capsaicin which is found in spicy food is lipid-based and passes right through the cell membrane. It attaches to VR-1 receptor and opens channel thus artificially creates the sensation of heat

78
Q

Where do GTO’s attach?

A

Attache to muscle fibres and tendon

79
Q

Is there 1 or multiple muscle fibres per GTO?

A

multiple

80
Q

What are GTOs innervated by?

A

type 1b afferent

81
Q

What are GTOs very sensitive to?

A

active force production

82
Q

What is the relationship between GTO firing rate and force output?

A

linear relationship

83
Q

What are the 4 types of joint receptors?

A
  1. Ruffini endings
  2. Pacinian corpuscles
  3. Golgi Endings
  4. Free nerve endings
84
Q

What do ruffini endings in the join code for?

A

joint position and intra-articular pressure

85
Q

What joint receptor codes for high frequency joint acceleration?

A

pacinian corpuscles

86
Q

What do golgi endings code for?

A

tension in ligaments, mainly at ends of ROM

87
Q

What joint receptors code for tissue damaging stimuli?

A

Free nerve endings

88
Q

Can joint receptors tell the difference between pressure, flexion/extension and intorsion/extorsion?

A

No

89
Q

Are joint receptors activated in all directions?

A

Yes

90
Q

What are joint receptors most useful for?

A

Knowing where we are at ends of ROM (joint position)

91
Q

Do joint angles give us info on joint angle?

A

No

92
Q

What amount of joint receptors increase their discharge with on direction of joint rotation?

A

1/4

93
Q

Are joint receptors useful for proprioception?

A

No

KNES 251 (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions