5 - Sensory Receptors; Pain Science Flashcards
1
Q
1st order neuron pathway?
A
info from sensory receptors to SC or brainstem
2
Q
2nd order neuron pathway?
A
info from SC or brainstem to thalamus
3
Q
3rd order neuron pathway?
A
info from thalamus to cerebral cortex
4
Q
___: when applied to a receptor, it triggers a graded membrane potential in receptor
A
stimulus
5
Q
___: converts stimulus energy into action potential
A
receptor
6
Q
___: of impulse over sensory pathway to CNS
A
conduction
7
Q
___: CNS receives impulse/s, integrates info and may prepare response
A
translation
8
Q
___ determines types of receptors that are activated and pattern of signal transmission
A
stimulation
9
Q
___ ___: specialized peripheral element of sensory neuron where sensation and perception begin
A
sensory receptors
- each receptor type is specialized and responds only to specific type and intensity of stimulus
10
Q
what receptors are neurons with free nerve endings?
A
simple receptors
11
Q
what receptors have nerve endings enclosed in connective tissue capsules?
A
complex neural receptors
12
Q
what receptors are cells that release neurotransmitter onto sensory neurons, initiating an action potential?
A
special senses receptors
13
Q
2 types of general senses and what falls under each?
A
- somatic: tactile, thermal, pain, proprioceptive
- visceral: conditions with internal organs
14
Q
examples of specialized senses?
A
smell, taste, vision, hearing, balance and equilibrium
15
Q
Exteroceptors- location? detect what?
A
- at or near body surface (superficial, cutaneous)
- detect external stimuli (light, heat, chemicals, pressure)
16
Q
Interoceptors - location? detect what?
A
- deep
- react to stimuli coming from internal body/organs (BP, blood pH)
17
Q
___: sensory receptors for mechanical pressure of touch, pressure, stretch, or vibration causes receptor to respond
A
mechanoreceptors
18
Q
___: receptors for chemicals released cells (including ones damaged by injury or disease) cause it to respond; includes smell, taste
A
chemoreceptors
19
Q
___: receptors detect changes in temperature
A
thermoreceptros
20
Q
each type of receptor has subset of _____ that are sensitive to stimuli that either damage or have potential to damage tissues
A
nociceptors
21
Q
__ receptors: respond continuously as long as stimulus is present
A
tonic
22
Q
tonic receptors are ___ acting
A
slow
23
Q
tonic receptors detect what type of sensory imput?
A
detect object pressure and form (static)
24
Q
___ receptors: adapt to continuous stimulus and then stop responding, even while stimulus is present
A
phasic
25
phasic receptors are ___ acting
fast
26
phasic receptors detect what type of sensory imput?
detect motion, vibration and rate of change
27
what is a sensory neuron receptive field?
area of skin innervated by 1 afferent neuron
28
Sensory neuron receptive fields have smaller receptive fields ____ and larger receptive fields ___.
distally, proximally
29
2 superficial cutaneous receptors?
1. meisners corpuscles
2. merkels disks
30
what do meisners corpuscles detect?
light touch, vibration
31
what do merkels disks detect?
pressure
32
2 subcutaneous receptors?
2. pacinian corpusle
2. ruffinis ending
33
what do pacinian corpuscles detect?
touch, vibration
34
what do ruffinis endings detect?
stretch of skin
35
mechanoreceptros (cutaneous) are ___ fibers
alpha beta (AB)
36
what do mechanoreptors detect?
light touch, vibration, skin stretch, skin pressure
37
free nerve endings (cutaneous) are ___ and ___ fibers
Alpha gamma and C
38
what do free nerve endings detect?
course touch (pleasant touch/pressure, tickle, itch)
pain
temperature
39
T or F - natural stimuli typically activate >1 type of receptor
T
40
4 attributes to conduction?
1. modality
2. location
3. intensity
4. duration
41
output signal (transmitter release) increases as ___ and/or ___ increases
duration, amplitude
42
Signal processing for integration occurs at what 3 levels in somatosensory system?
1. receptor level
2. circuit level
3. perceptual level
43
Speed of information is determined by:
- axon ___
- amount of axon ____
- # of ____ in pathways
diameter
myelination
synapses
44
___ ___: graded membrane potential in receptors
receptor potential
45
__: synapses can spread action potentials to several areas of CNS
divergence
46
___: synapses can focus action potentials from several sensory neurons onto narrowed areas of CNS
convergence
47
T or F - sensory nerve tracts carry impulses to respective region of brain
T
- remember the sensory map of homunculus
48
what test electrical stimulation to peripheral nerve, comparing results to normal?
nerve conduction velocity testing (NCV/NCS)
49
what 3 things does a nerve conduction velocity test look for?
1. distal latency - time from stim to distal recording site
2. amplitude - # axons conducting
3. conduction velocity - indication of myelination
50
what test is done to test peripheral and central pathways? Done by stimulation at distal site recording more proximally and cerebral cortex
somatosensory evoked potentials (SSEP)
51
pathology of peripheral nerve is ____
neuropathy
52
Nerve compression impacts what nerves first and what nerves last?
nerve compression impacts large myelinated axons first and smaller nociceptive thermal and autonomic axons last
53
Order of sensory loss?
1. conscious proprioception and light touch
2. cold
3. fast, sharp, stinging pain
4. heat
5. slow, aching pain
54
what injuries can cause sensory ataxia?
injury to peripheral sensory nerves, dorsal roots, dorsal columns of SC or medial lemnisci
55
patients with ____ ataxia will have similar motor performance eyes open/closed
cerebellar
56
proprioception/kinesthesia will be intact with ____ ataxia and impaired/absent with ____ ataxia
cerebellar, sensory
57
SHINGLES OR HERPES ZOSTER:
- painful skin rash with blisters following a ___ pattern
- caused by: varicella zoster virus causes chicken pox and infects __ ___ __
- virus remains latent in sensory ganglia for many years
- virus breaks out of nerve cells and travels distally causing painful eruptions on skin
- treatment: antiviral drugs within 72 hrs post onset
dermatome
dorsal root ganglion
58
T or F - nociceptors are free nerve endings that respond to noxious stimuli
T
- located within skin, muscle, joints
- fast and slow pain carried by Alpha gamma or C fibers to SC
59
____ pain: acute or chronic tissue injury stimulates nociceptors to cause events that become perception of pain
nociceptive
60
_____ pain: malfunction of neural pain regulating processes causes pain without the presence of tissue injury
non-nociceptive
- includes neuropathic pain, central sensitivity syndromes, pain syndromes
61
___ and ___ ___ can sensitize free nerve endings in the periphery
edema, endogenous chemicals
62
Pain inhibition occurs thru ___ ___ pathways and ___ ___ system
descending analgesic
endogenous opiod
63
central processing: ___ and ___ areas activated during perception of pain
cingulate, insular
64
3 examples of endorphins? (endogenous opiods)
enkephalins, dynorphin and B-endorphins
65
brain regions that have opiate receptors that bind with both endorphins and opiates?
- rostral ventromedial medulla
- periqueductal gray in midbrain
- locus coeruleus in pons
66
SC has inhibtory neurons - which 2?
enkephalin and dynorphin
67
5 locations of pain inhibition?
1. periphery
2. dorsal horn
3. brainstem
4. hormonal system
5. cortical level
68
periphery pain inhibition?
decrease synthesis of prostaglandins
69
dorsal horn pain inhibition?
release of enkephalin and dynorphin
70
brainstem pain inhibition?
neuronal descending system - periaqueductal gray, rostral VM medulla, locus coeruleus
71
hormonal system pain inhibition?
periaqueductal gray and pituitary gland
72
cortical level pain inhibition?
- prefrontal lobe, insular lobe, cingulate cortex
- spinolimbic, spinomesencephalic and spinoreticular tracts
73
nociceptors that are excessively reactive to stimuli demonstrate ___ ___
peripheral sensitization
74
__ ___: pain that is perceived as coming from site distinctly different from actual origin site
referred pain
- usually referred from visceral tissue to skin
- occurs due to convergence of nociceptive and somatic information
75
chronic pain as disease: ____ pain: neural dysfunction creates pain without evidence of tissue damage
primary
76
examples of primary pain?
1. fibromyalgia
2. complex regional pain syndrome
3. chronic nonspecific low back pain
4. migraine HA's
77
___ ___: central neurons respond excessively/disproportionately to continuing nociceptive input, with the central neuronal activity lasting longer than actual tissue injury
central sensitization
78
___: abnormal sensation that is painless with no nociceptor stimulation
- dysfunction of neurons anywhere along the pathway
- typically tingling sensation
- different from neuropathic pain
parasthesia
79
___ ___: pain that arises as a direct result of a lesion or disease that affects the somatosensory system
neuropathic pain
80
central sensitazation characterized by ____: unpleasant abnormal sensation that can occur on its own or with stimulation
- burning, shooting or electrical sensation like hitting your "funny bone"
dysesthesias
81
4 types of dysesthesias?
1. allodynia
2. hyperalgesia
3. spontaneous pain
4. temporal summation
82
___: pain that is caused by something that normally wouldn't cause pain
allodynia
- "cross-talk" hypothesized between light touch and nociceptor pathways
- microglia abnormal activation may be implicated
83
___ ___: stimuli that are normally mildly painful in injured tissue are causing excessive sensitivity
primary hyperalgesia
84
___ ___: pain spreads to uninjured areas close to injury site
secondary hyperalgesia
85
__ __: pain unrelated to external stimulus
spontaneous pain
86
___ ___: increased pain due to repeated stimulus or continued presence of single stimulus
- "wind up" occurs at cellular level due to heightened output of 2nd order neurons within dorsal horn or trigeminal spinal nucleus
temporal summation
87
___ __ are locations that are outside of the nociceptor or soma that trigger action potentials
ectopic foci
88
___ ___:
- also called cross talk
- lack of insulation due to demyelination allows an action potential in 1 neuron to cause an action potential in another neuron
ephaptic transmission
89
Long lasting central sensitization facilitates rewiring of CNS connections. New synapses between ___ fibers and 2nd order neurons replace ___ fiber connections so that AB fibers now carry nociceptive information
AB, C
- cerebral cortex also shows signs of reorganization
90
Neuropathic pain: ___ ___: caused by lesion to CNS, localized to area of body deafferented by the lesion
- burning, shooting, aching, freezing, tingling pain
central pain
91
__ ____ ___ is due to absence of sensory inputs causing neurons in central nociceptive pathways to be overly active
phantom limb pain
- adaptive stuctural reorganization is seen in periphery with altered membrane channels and hyperexcitability of neurons, degenreation of dorsal root ganglion and dorsal horn of SC, thalamus and cerebral cortex
- amount of cerebral cortex reorganization is correlated to amount of phantom pain
92
therapists need to address the "3 D's" of chronic pain which are?
1. distress
2. disuse
3. disability
93
