Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Neurology > The Somatosensory System 1 > Flashcards

The Somatosensory System 1 Flashcards

(78 cards)

Start Studying
1
Q

What does the somatosensory system not mediate?

A

Special senses

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

What does the somatosensory system include the modalities of?

A 
Touch, pressure, vibration
Joint and muscle position 
Temperature
Pain
Itch
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Mechanosensation is?

A

Touch
Pressure
Vibration

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

Proprioception is?

A

Joint and muscle position

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

Thermosensation is ?

A

Temperature

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

Nocioception is?

A

Pain

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

Pruriception is?

A

Vibration

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

What does stimuli do to the nerve terminal?

A

Opens CATION selective ion channels to elicit a depolarising receptor potential

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

Describe the amplitude of generator potential.

A

GRADED
+
Proportional to stimulus intensity

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

What triggers ‘all or none’ action potentials? What is the frequency of these action potentials proportional to?

A

Low current flow

At a frequency proportional to the amplitude of the receptor potential

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

Sensory neurones transduce a stimulus into ……… activity?

A

ELECTRICAL

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

What is a muscle spindle?

A

A sensory structure in skeletal muscle

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

What are muscle spindles activated by?

A

STRETCH

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

Outline the process through which a spindle is transduce into electrical activity.

A
  1. Graded receptor potential
  2. Triggers ‘all or none’ AP
  3. AP
  4. Output graded release of neurotransmitter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the neurotransmitter?

A

Glutamate

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

What is meant by ‘modality’?

A

The principle type of adequate stimulus that is transduce into an electrical signal by a primary afferent neurone

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

What do low threshold units respond to?

A

Low intensity stimuli
(non damaging and non painful)
e.g low threshold mechanoreceptors and low threshold thermosensors

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

Give an example of what low threshold mechanoreceptors sense?

A

Mediate touch, vibration and pressure

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

Give an example of what low threshold thermosensors sense?

A

Cold, cool, indifferent, warm and hot

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

What do high threshold units mediate?

A

High intensity stimuli

Noxious and potentially damaging

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

What is another name for high threshold units?

A

Mechanical nociceptors

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

What do thermal nociceptors respond to?

A

Extreme degrees of heat (>45°C), or cold (< 10-15°C)

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

What do chemical nociceptors respond to?

A

Substances in tissue (as found in inflammation) e.g. prostaglandins, bradykinin, serotonin, histamine, K+, H+ and ATP and many others

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

What do polymodal nociceptors respond to?

A

At least 2 of the above types

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is adaptation?
A feature of primary sensory neurones that determines whether they change their firing rate only in response to a stimulus of changing intensity, or fire continuously throughout a constant stimulus
26
Slowly Adapting (SA) Tonic/Static Response is?
Continuous information to the CNS while terminal deformed
27
What does SA respond give information about? Give an example.
Position, degree of stretch or force | e.g stretch receptors
28
Rapidly Adapting (RA) Phasic/Dynamic Response detects changes in?
Stimulus strength e.g rate of movement
29
What is the number of impulses proportional to? Give examples.
Rate of change of stimulus | e.g Some muscle spindle afferents, hair follicle afferents
30
Very Rapidly Adapting (very RA) Very Phasic/Dynamic Response responds to?
Only very fast movements | e.g rapid vibration
31
Give an example of very RA.
Pacinian corpuscles
32
Aa
THICK myelination | e.g proprioceptors of skeletal muscle
33
C
NO myelination | e.g temperature, pain, itch
34
What is the receptive field of an afferent neurone?
The region that when stimulated with an adequate stimulus causes a response in that neurone
35
For primary afferent neurones, the RF is the site of?
The peripheral terminal
36
A patch of skin contains many overlapping RF’s innervated by individual primary afferent fibres
TRUE
37
There is wide differences in two point discrimination
TRUE
38
How do most peripheral nerves communicate with the CNS?
Via the spinal cord
39
What is the innervation of the anterior head by?
The trigeminal system
40
If a single dorsal root is cut, why does the corresponding dermatome not lose all sensation?
Because of the degree of overlap with the region of adjacent dorsal roots
41
Where does shingles infect?
Dorsal root ganglion neurones
42
What virus causes shingles?
Varicella zoster
43
What does VZV also cause?
Chickenpox
44
What does the VZV do in adulthood?
REACTIVATES in a single ganglion
45
What is grey matter of the spinal cord divided into?
Dorsal horns Ventral horns 10 distinct laminae of rexed
46
Name the 3 broad categories that the somatosensory system can be divided into?
Exteroceptive Proprioceptive Enteroceptive
47
Exteroceptive division is?
(cutaneous senses) registers information from the surface of the body by numerous receptors
48
Proprioceptive division is?
Monitors posture and movement (sensors in muscle and tendons and joints)
49
Exteroceptive division is?
Reports upon the internal state of the body and is closely related to autonomic function
50
Describe the pathway of neurones in the somatosensory system.
1. 1st order neurone 2. 2nd order neurone 3. 3rd order neurone 4. Somatosensory cortex
51
Describe the 1st order neurone and its location.
Primary sensory afferent | Cell body located in dorsal root ganglion
52
Describe the 2nd order neurone and its location.
Projection neurone | Cell body located in dorsal horn of spinal cord or brainstem nuclei
53
Describe the 3rd order neurone.
Projection neurone | Cell body located in thalamic nuclei
54
What is 'modality'?
Primary afferent neurons are especially ‘tuned’ to respond to a specific type of energy (the adequate stimulus) that normally excites them underlying the sensation that they subserve
55
How is two point discrimination tested?
applying simultaneously two sharp point stimuli, separated by a variable distance, at different sites on the body surface and get person to close eyes and say if they feel one or two points
56
Name the 4 cell types of hairless skin.
``` Merkel cell neutrite complexes (SA1) Meissner corpuscle (FA1) Ruffini endings (SA2) Pacinian corpuscles (FA2) ```
57
Describe merkel cell neutrite complexes.
Formed from many expanded nerve terminals, each closely associated with a Merkel cell as a ‘synapse-like’ structure
58
Where are SA1's located?
Basal epithelium
59
SA1's have .... sensory acuity
HIGH
60
What are SA1's sensitive to?
Pressure, texture, and are extremely sensitive to the edges of objects
61
SA1' are....
MECHANOSENSITIVE
62
Describe Messiener corpuscles
Formed from a capsule in which several axons zigzag between modified Schwann cells (teloglia)
63
Where is FA1's located?
Close to the basal epithelium
64
FA1's have HIGH sensory acuity
TRUE
65
What are FA1's sensitive to?
Sensitive to stroking, flutter, low frequency vibration
66
What allows for the detection of textured surfaces of FA1's?
Small RF and high density
67
Describe Ruffini endings.
Collagenous core in which axons branch
68
Located in dermis (also joint capsules) of both glabrous and hairy skin describes what cell type?
Ruffini endings
69
What are ruffini endings sensitive to?
Drag (shearing forces)
70
Describe pacinian corpuscles.
Large 'onion-like' structures
71
Where are pacinian corpuscles located?
In SC tissue close to the periosteum of bone
72
What are pacinian corpuscles sensitive to?
Very sensitive to vibration over frequency range higher (approx. 200 – 300 Hz) than Meissner corpuscle
73
What do pacinian corpuscles act as?
'event detectors' | during the manipulation of an object
74
Hairy skin contains all receptors except? What are they replaced by?
Meissner corpuscles | Hair units
75
What is a 'hair unit'?
Comprise follicular (free) nerve endings that either wrap around the follicle (circumferential fibres), or parallel to it (palisade fibres)
76
A single afferent fibre innervates many follicles
TRUE
77
Units are responsive to the bending of hairs, which increases, or decreases their firing when the hair is in motion, but not when static
TRUE
78
Sensory units may be slowly, or fast, adapting
TRUE

Neurology (42 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions