Somatosensory Processing Flashcards
1
Q
Deformation of the DRG (free or encapsulated) by a mechanical stimulus _____ the threshold needed to evoke an action potential.
A
lowers
2
Q
High-threshold channels characterize _____ (receptorss for pain).
A
nociceptors
3
Q
Nociceptors are found predominantly in _____ _____.
A
smaller DRG
4
Q
Nociceptors are activated by _____ pressures.
A
higher
5
Q
Proprioceptors
A
Give information about the position of limbs and body in space.
Muscle spindles
Goldgi tendon organs
6
Q
Stretching a mucle activates _____ on two types of afferent fibers:
A
mechanoreceptors
group 1a
group 2
7
Q
Group 1a afferent fibers
A
large myelinated fibers
repidly adapting
8
Q
Group 2 afferent fibers
A
myelinated fibers
slowly adapting
9
Q
Tension of intrafusal fibers is also controlled by _____.
A
gamma motor neurons
from dorsal horn spinal cord
10
Q
Large muscles for coarse movements have _____ spindles.
A
few
11
Q
Extraocular muscles and uscles in the neck and hand have ____ spindles.
A
many
require precise control
12
Q
Muscle spindles detect changes in _____.
A
muscle tension
13
Q
Tactile afferents from body:
A
Dorsal column - medial lemniscal system
14
Q
Afferents from face use the _____ (_____).
A
trigeminothalamic system
Trigeminal ganglion
15
Q
Merkel receptors have _____ responses.
A
sustained
16
Q
Meissner receptors are _____.
A
rapidly adapting
17
Q
Pacinian receptors are _____.
A
rapidly adapting
18
Q
Ruffini receptors have _____ responses.
A
sustained
19
Q
Merkel receptors are responsible for _____ and _____ perception.
A
form
texture
20
Q
Meissner receptors are responsible for _____ and _____.
A
motion detection
grip control
21
Q
Pacinian receptors are responsible for _____ perception and _____.
A
vibration
tool use
22
Q
Ruffini receptors are responsible for _____, _____, and _____.
A
tangential force
hand shape
motion direction
(stretch)
23
Q
Slowly adapting afferents convey information about _____, such as size and shape.
A
spatial attributes
24
Q
Rapidly adapting afferents convey information about ______: dynamic qualities of the stimulus.
A
changes in ongoing stimulation
25
Sensory axons are classified according to their _____, which governs their _____ and their _____.
diameter
myelination
conduction velocity
26
Dermatome
Cutaneous innervation related to a single spinal nerve
27
sensation
transduction
| transmission
28
perception
inference
deduction
follow-up
29
5 primary tasks of sensory systems
```
transduction
transmission
inference
deduction
follow-up
```
30
5 qualities of information to encode
```
modality
intensity
duration
location
salience
```
31
5 factors that influence success or failure
```
fatigue
adaption
sensitization
overlap/redundancy
damage/overload
```
32
Dorsal root ganglia
contain the sensory neurons of the somatosensory system
33
Dorsal root is responsible for _____.
sense
34
Ventral root is responsible for _____.
motor
35
The _____ system is responsible for touch perception.
dorsal column-medial lemniscus system
36
The _____ is responsible for pain perception.
anterolateral system
37
The _____ projects to the cerebellum and controls timing of muscle contractions.
dorsal spinocerebellar tract
38
Proprioceptive afferents from the body lead to the _____ and _____.
cerebellum
| dorsal column nuclei
39
The _____ somatosensory thalamus contains _____ afferents from the body.
central posterior lateral
| medial lemniscus
40
The _____ somatosensory thalamus contains _____ afferents from the face.
ventral posterior medial
| trigeminal lemniscus
41
the somatosensory cortex contains _____ __, __, _, and _.
```
Brodmann's areas
3a
3b
1
2
```
42
The _____ is a representation of the human body from the _____.
homunculus
| somatotopic map
43
_____ serves as obligatory first step in cortical processing of somatosensory information.
Brodmann's area 3b
44
_____ are functioal modules of the cortex.
Columns
45
Columns in the somatosensory cortex are _____.
functionally distinct
46
Reorganization of cortical maps in response to altered functional input is known as _____.
plasticity
47
Nociception
The neural encoding and processing of noxious stimuli
48
Noxious stimuli
stimuli that can elicit tissue damage and activate nociceptors
49
Nociceptors are sensory receptors that detect signals from _____ and respond to _____ released.
damaged tissue
| chemicals
50
Nociceptors are _____ found in the skin, muscle, joints, bone, and viscera.
free (bare) nerve endings
51
Pain processing is _____ of normal cuteaneous processing.
independent
52
Peripheral axons responsible for normal stimulation _____ their frequency in response to painful stimuli.
do not increase
53
Nociceptive afferents only fire when _____.
stimuli reach high intensities
54
Direct stimulation of large fibers (1a, II, AB) _____.
does not produce pain
55
Peripheral nociceptive axons terminate in "_____."
free endings
56
Nociceptors are found on _____ fibers (_, _)
small
Ad
C
57
C fibers are _____ and respond to _____, _____, and _____ stimuli.
polymodal
thermal
mechanical
chemical
58
_____ fibers lack myelination.
C
59
Type I Ad fibers respond to dangerous _____ and _____ stimulation.
mechanical
| chemical
60
Type II Ad fibers respond to _____ stimulation.
thermal
61
_____ respond only to intense mechanical stimulation such as pinching, cutting, or stretching.
High threshold mechano-nociceptors
62
_____ respond to intense mechanical stimulation as well as to thermal stimulation.
Thermal nociceptors
63
_____ respond only to chemical substances.
Chemical nociceptors
64
_____ respond to all high intensity stimuli.
Polymodal nociceptors
65
_____ include high-threshold mechanoreceptors, polymodal nociceptors, and ''silent'' nociceptors.
Joint nociceptors
66
_____ include mechanoreceptors, thermal, silent and chemical nociceptors.
Visceral nociceptors
67
C and Ad fiber nerve endings contain _____ that respond to temp, pressure, and inflammatory agents.
transient receptor potential (TRP) channels
68
TRPV1 is activated by _____, _____, _____, and _____.
heat
anandemide
capsaicin
allyl isothiocyanate
69
TRPV1
Transient receptor potential vanilloid type-1
70
TRPV1 channels are also known as _____ and _____.
capsaicin receptors
| vanilloid receptor 1
71
_____ are produced peripherally in response to injury.
Endovanilloids
72
ASIC
acid-sensing ion channel
73
Hyperalgesia
Increased sensitivity to painful stimuli
74
Hyperalgesia has a _____ effect at the level of the nociceptors.
peripheral
75
Tissue damage and inflammation release inflammatory mediators, such as _____, _____, and _____ which increase the sensitivity of nociceptors to _____.
prostaglandins
histamin
substance P
noxious stimuli
76
Most sensitizing pro-inflammatory agents activate the _____ pathway.
phospholipace C
77
Phospolipace C pathway phosphorylates TRPV1, leading to _____.
sensitization of TRPV1
78
Allodynia
Pain sensation in response to non-painful stimuli
79
Allodynia results from an increase in excitability of _____.
dorsal horn neurons
80
The _____ localizes painful or thermal stimuli and leads to the _____.
```
spinothalamic tract (lateral and anterior)
thalamus (central lateral nucleus)
```
81
The _____ causes alertness and arousal in response to painful stimuli and leads to the _____.
```
spinoreticular tract
reticular formation (through ret.form. of medulla and pons)
```
82
The _____ orients the eyes and head towards the stimuli and leads to the _____.
spinotectal tract
| tectum (through periaqueductal gray matter)
83
The dorsal root ganglia pathway goes through _____.
Lissauer's tract
84
Crossing of the anterolateral tract from left to right spinal cord occurs at the _____.
decussation
85
Visceral pain misperceived as somatic pain is called _____.
referred pain
86
Non-nociceptive fibers of the anterolateral tract terminate in _____.
layer 5
87
Unilateral spinal cord lesions lead to "dissociated sensory loss":
contralateral: _____
ipsilateral: _____
reduction in pain/temp sensation
| reduction in touch/pressure/vibration/proprioception
88
The anterolateral system from the body runs through the _____ and the _____.
spinothalamic tract
| Ventral posterior lateral nucleos of the thalamus
89
The anterolateral system from the face runs through the _____ and the _____.
Trigeminothalamic tract
| Ventral posterior medial nucleus of the thalamus
90
Sensory discriminative aspects of pain
location
intensity
quality
91
Affective motivation aspects
fear
| anxiety
92
The anterolateral system is divided into _____ and _____.
sensory-discriminative
| affective-motivational
93
The sensory-discriminative anterolateral system leads to the _____.
somatosensory cortex
94
Stimulation of the periaqueductal gray in the midbrain is _____.
analgesic
95
_____ in the spinal cord modulate pain perception.
Local interactions
96
Nociceptive information is modulated by simultaneous activity in _____.
touch fibers
97
Opiod
Peptide that binds to the same posynaptic receptors as opium
98
_____ is the active ingredient in the sap/seeds of opium poppies.
Morphine
99
Morphine, heroin, and synthetic opiates such as methadone and fentanyl are potent _____.
analgesics
100
3 groups of endogenous opioid receptor ligands:
endorphins
enkephalins
dynorphins
101
_____ modulate transmission of ascending pain signals.
Descending systems
102
_____ are released directly in the spinal cord to blunt the effects of nociceptor activation.
Enkephalins
