Brainscape's Knowledge GenomeTM

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


See full index

BAB > The Somatosensory System > Flashcards

The Somatosensory System Flashcards

1
Q

What is the function of A alpha fibres?

A

To carry information from proprioceptors.

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

What is the function of A beta fibres?

A

To carry tactile information from mechanoreceptors of the skin.

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

What is the function of A delta fibres?

A

To carry pain and temperature information.

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

What is the function of C fibres?

A

To carry pain, temperature and itch information.

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

Define 2 point discrimination.

Why is this useful?

A
  • The minimum distance by which two stimuli must be separated to allow an individual to discriminate between them.
  • If two stimuli are within the same receptive field, they will be interpreted as one point of stimulation.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define dermatome.

A

An area of skin innervated by afferent axon fibres from a single spinal nerve root.

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

Define adequate stimulus.

A

The property of a sensory receptor that determines the type of energy to which it will respond with the initiation of an action potential.

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

Which part of a neurone determines the adequate stimulus?

A

The nerve ending.

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

Which part of a neurone determines the signal threshold?

A

The nerve ending.

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

What is the function of slow adaptation and non-adaptation?

How does slow-adaptation and non-adaptation respond to unchanging stimuli?

Why is this useful?

A
  • Slow adaptation and non-adaptation function to detect the strength of a stimulus.
  • When the intensity of a stimulus stops changing , the frequency of action potentials generated by slow-adapting receptors decreases but very slowly. Non-adapting receptors do not change action potential frequency at all until the stimulus changes intensity again.
  • This is important for stimuli which an individual needs to stay aware of, for example pain or stretch (of skin).
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the function of fast adaptation?

How does fast-adaptation respond to unchanging stimuli?

Why is this useful?

A
  • Fast adaptation functions to detect the rate of change of a stimulus.
  • When the intensity of a stimulus stops changing, the frequency of action potentials generated by fast-adapting receptors decreases quickly.
  • This is important for stimuli which an individual can stop paying attention to when the stimulus is no longer important, for example tactile (touch) receptors.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

List the cutaneous sensory receptors.

List the stimuli to which each receptor responds.

A

1 - Mechanoreceptors (touch, pressure and vibration).

2 - Thermoreceptors (temperature).

3 - Nociceptors (noxious stimuli).

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

List the types of mechanoreceptors.

Which are located in the superficial layers of the skin?

Which are located in the deep layers of the skin?

A

Superficial layers:

1 - Meissner’s corpuscle.

2 - Merkel’s receptor.

Deep layers:

3 - Ruffini’s corpuscle.

4 - Pacinian corpuscle.

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

In which layer of the skin are Meissner’s corpuscles found?

A

In the papillary (superficial) dermis of glabrous skin.

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

List the stimuli to which Meissner’s corpuscles respond.

A

1 - Light touch.

2 - Vibration.

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

What type of adaptation do Meissner’s corpuscles exhibit?

What is the implication of this?

A
  • Fast adaptation.

- They require constantly changing stimuli.

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

Where are Merkel’s receptors found?

A
  • In high densities in the epidermis of the digits and around the mouth.
  • In low densities in other glabrous skin.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

To which stimulus do Merkel’s receptors respond?

A

Light touch.

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

What type of adaptation do Merkel’s receptors exhibit?

A
  • Slow adaptation.

- They can sustain a constant light touch stimulus.

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

What apparatus forms Merkel’s receptors?

A

They are formed of specialised keratocytes, which are fibroblasts of the cornea.

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

Where are Ruffini’s corpuscles found?

A

In the papillary (superficial) dermis of glabrous skin.

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

List the stimuli to which Ruffini’s corpuscles respond.

A

1 - Lateral movement (stretching) of the skin.

2 - Deep touch.

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

What type of adaptation do Ruffini’s corpuscles exhibit?

A

Slow adaptation.

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

What apparatus forms Ruffini’s corpuscles?

A

Networks of collagen fibres.

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

Where are Pacinian corpuscles found?

A

In the reticular (deep) dermis of both glabrous and hairy skin.

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

List the stimuli to which Pacinian corpuscles respond.

A

Strong stimuli:

1 - Strong poking.

2 - Deep touch.

3 - High-frequency vibration (this is the primary stimulus).

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

What type of adaptation do Pacinian corpuscles exhibit?

A

Fast adaptation.

28
Q

What apparatus forms Pacinian corpuscles?

What is the function of this apparatus?

A
  • Nerve endings encapsulated in fluid-filled membranes.

- To absorb the force of mechanical stimuli.

29
Q

Where are hair follicle receptors found?

A

At the base of a hair follicle in the dermis.

30
Q

To which stimulus do hair follicle receptors respond?

A

Light touch (by deflection of the hair follicle).

31
Q

What type of adaptation do hair follicle receptors exhibit?

A

Fast adaptation.

32
Q

What apparatus forms hair follicle receptors?

A

They are just nerve fibres wrapped around the base of the hair follicle.

33
Q

What type of adaptation do cutaneous thermoreceptors exhibit?

A

Slow adaptation.

34
Q

List the two subcategories of cutaneous thermoreceptors.

A

1 - Thermoreceptors that respond to hot temperature.

2 - Thermoreceptors that respond to cold temperature.

35
Q

If cutaneous thermoreceptors exhibit slow adaptation, why are they poor indicators of absolute temperature and very sensitive to changes in temperature?

A

Because the sense of temperature comes from the comparison of the signals from hot and cold thermoreceptors.

36
Q

What apparatus forms cutaneous thermoreceptors?

A

They are just free nerve endings.

37
Q

To which family of ion channels do thermoreceptor ion channels belong?

Describe the nature of the ion channels that belong to this family.

What is the function of these ion channels?

A
  • The transient receptor potential family.
  • They are nonspecific cation channels (usually Na+).
  • These are the ion channels which cause cation influx in order to open the voltage gated channels that cause depolarisation (if the threshold is reached).
38
Q

What is the name of the ion channels that belong to cold cutaneous thermoreceptors?

When do these channels open?

A
  • TRPM8.

- These channels open between 10 and 38 degrees C.

39
Q

What is the name of the ion channels that belong to hot cutaneous thermoreceptors?

When do these channels open?

A
  • TRPV3 / 4.

- These channels open between 29 and 45 degrees C.

40
Q

What substance opens TRPM8 channels?

A

Menthol (this is why minty things give a cold sensation).

41
Q

Which fibres carry temperature information from cold cutaneous thermoreceptors?

Which fibres carry temperature information from hot cutaneous thermoreceptors?

A
  • Cold receptors send their action potentials via both C and A delta fibres.
  • Hot receptors send their action potentials via C fibres only.
42
Q

Why might high temperatures cause a paradoxical cold perception?

A

Because cold receptors are also excited by high temperatures starting at around 45 degrees C.

43
Q

To which stimuli do cutaneous nociceptors respond?

A

Any stimulus capable of damaging tissue.

44
Q

What type of adaptation fo cutaneous nociceptors exhibit?

A

Non-adaptation.

45
Q

What can be said about the threshold of cutaneous nociceptors?

A

It is relatively high.

46
Q

What apparatus forms cutaneous nociceptors?

A

They are just free nerve endings.

47
Q

List the two subcategories of cutaneous nociceptors.

A

1 - High threshold mechanoreceptors.

2 - Polymodal nociceptors.

48
Q

Which fibres carry temperature information from high threshold mechanoreceptors?

Which fibres carry temperature information from polymodal nociceptors?

A
  • High frequency mechanoreceptors send their action potentials via A delta fibres.
  • Polymodal nociceptors send their axons via C fibres.
49
Q

What is the difference between the sensation that arises from high threshold mechanoreceptors and polymodal nociceptors?

A
  • High threshold mechanoreceptors produce a well-localised pricking pain.
  • Polymodal nociceptors produce a poorly-localised burning pain.
50
Q

List the stimuli to which polymodal nociceptors respond.

A

1 - Mechanical stimulus.

2 - Damaging heat.

3 - Noxious chemicals.

51
Q

What is the name of the ion channels that belong to hot polymodal nociceptors?

A

TRPV1.

52
Q

Which substance opens TRPV1 channels?

A

Capsaicin.

53
Q

List the 2 sensory receptors that give rise to proprioceptive information.

A

1 - Muscle spindle / intrafusal fibres.

2 - Golgi tendon organs.

54
Q

List 5 properties of the musculoskeletal system that are conveyed in proprioception.

A

1 - Joint position.

2 - Muscle length.

3 - Muscle movement.

4 - Acceleration.

5 - Tension / force.

55
Q

What are muscle spindles / intrafusal fibres?

A

Specialised muscle fibres contained within a fibrous capsule.

56
Q

What type of A alpha fibres carry proprioceptive information from muscle spindle?

A

Type 1A afferents.

57
Q

What type of A alpha fibres carry proprioceptive information from golgi tendon organs?

A

Type 1B afferents.

58
Q

What are golgi tendon organs?

A

Encapsulated collagen fibres that are in series with muscle at the junction of the muscle and the tendon.

59
Q

To which stimulus does muscle spindle respond?

To which stimulus does golgi tendon organ?

A
  • Muscle spindle responds to stretch of muscle.

- Golgi tendon organs respond to tension at the junction of the muscle and tendon.

60
Q

List the 2 main sensory pathways.

In which areas of the spinal cord do these pathways ascend?

A

1 - Lemniscal pathway (dorsal columns).

2 - Spinothalamic pathway (anterolateral tracts).

61
Q

List the stimuli that excite fibres in the lemniscal pathway.

A

1 - Touch.

2 - VIbration.

3 - Proprioception.

62
Q

List the stimuli that excite fibres in the spinothalamic pathway.

A

1 - Pain.

2 - Temperature.

63
Q

Which pathway is responsible for two-point discrimination?

A

The lemniscal pathway.

64
Q

List the fibres that ascend the spinothalamic pathway.

A

1 - A delta fibres.

2 - C fibres.

65
Q

Which fibre type ascends the lemniscal pathway?

A

A beta fibres.

BAB (34 decks)

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