Somatosensory System Flashcards
the structural organization that gives rise to ____ ensures that location of the stimulus as applied to the body can be accurately identified
somatotopic mapping
somatosensory signals from the skin project into the brain via ______ , allowing precise perception of location on the body surface
labeled lines
Somatosensory fibers from the viscera have a relatively _____ resulting in poor discrimination of the precise location
Large receptive field
our brain may _____ arising from visceral receptors to a somatic location due to lack of discrimination
refer neural signaling
large diameter, heavy myelin sheath (fastest conducting)
A-fiber (Type 1)
medium diameter, myelinated
A-beta (Type 2)
small diameter, myelinated
A-delta
unmyelinated (slowest conducting)
C
What are the two mechano receptors in the superficial skin?
Merkel’s disk
Meissner’s corpuscle
What are the two mechano receptors of the deep skin?
Ruffini corpuscle
Pacinian corpuscle
Mechano receptors of the superficial skin are what kind fiber?
A alpha
Mechano receptors of the deep skin are what kind of fiber?
A beta
maintains signaling (at a relatively steady frequency) throughout the duration that the stimulus is applied
Slow adapting
maintains signaling just while the stimulus intensity is changing
Rapidly adapting
_____ corpuscles are slowly adapting (deep skin)
Ruffini’s
_____ corpuscles are rapidly adapting (deep skin)
Pacinian
_____ disks are slowly adapting (superficial skin)
Merkel’s disk
______ corpuscles are rapidly adapting (superficial skin)
Meissner’s
heat receptors [warm to hot]: 95 to 110°F (C fibers)
Are what kind of fibers?
C fibers
cold receptors [cool to cold]: 85 to 60°F are what kind of fibers?
Ad fibers
T/F thermoreceptors are most sensitive to changes in temperature; most adapt rapidly to sustained temperature
True
what differentiates a nociceptor from a non-nociceptive somatosensory receptor is the receptor’s _____
stimulus threshold
Nociceptors have a ____ stimulus threshold, compared to non-nociceptive receptors
higher
strength of the nervous signaling that the receptor generates in response to a given strength of stimulus intensity
receptor sensitivity
a change in the peripheral receptor sensitivity to a given stimulus
primary:
a change in the strength of synaptic transmission of peripheral afferent signals arising from the nociceptors to the second order relay neurons
secondary
sensitization (an increase in the receptor sensitivity)
hyperalgesia
desensitization (a reduction in the receptor sensitivity)
analgesia
Change in peripheral sensitivity to a given stimulus
Primary
A change of synaptic transmission of peripheral afferent signals arising from the nociception to the second orders relay neurons
Secondary
What chemicals are secreted by damaged cells to activate nociceptors
H+
Serotonin
Bradykinin
Histamine
Primary hyperalgesia may arise from sensitization of _____
Peripheral nociceptors
To prevent further damage the surrounding tissues become ____
Hyperalgesic (sensitive)
Secondary hyperalgesia may arise from sensitization of the _______ for ascending nociceptive signaling
Dorsal horn synaptic relay
Pain due to a stimulus that does not normally provoke pain
allodynia
Pain that initiated or caused by a primary lesion or dysfunction within the central nervous system
Central Pain
Pain in the distribution of a nerve
Neuralgia
Pain initiated or caused by a primary lesion, dysfunction, or transitory perturbation in the peripheral or CNS
Neurogenic pain
The specific field for a set of neurons
Receptive field
Axon hillock for a receptor
Trigger zone
Summation of multiple inputs
Intigration
Strengthening or lessening the response of each relay neuron via modulation
Processing
Amplifies synaptic transmission
Excitatory
Diminishes synaptic transmission
Inhibitory
Somatosensory inputs flowing into the dorsal horn will ___ inhibitory interneurons aswell as it’s own relay neuron
Excite
______ acts to fine tune the sense of touch thus the area surrounding the point of contact will not be inadvertently stimulated
Inhibitory neuron
relay neurons to afferent sensory signaling are ____ through both feedforward and feedback inhibitory pathways
restrained
Inhibition coming from a parallel first order neuron
Feedforward inhibition
Inhibition coming from a parallel second order neuron
Feedback inhibition
T/F the brain can inhibit some sensory input from other non-essential stimuli
True
Suppressing other background signals
Sculpting
Nociceptive A-delta and C fibers project to second order neurons within ____ of the dorsal horn
Lamina I and V
____ is the theory behind pain modulation
Gate control theory
In gate control- what fiber is conveying pain
C-fiber
In gate control- what fiber is trigger inhibition of pain
A-beta
In gate control- the C fiber comes from what kind of receptor?
nociceptor
In gate control- the A beta fiber comes from what kind of receptor?
Mechanoreceptor
Inhibitory interneuronal gating is dependent upon the ____ between nociceptive and non-nociceptive inputs
Balance
