structure and function of peripheral sensory receptors Flashcards
Dorsal root ganglion: is part of_____ thus somatosensory is in the ______ system
PNS
PNS
sensory pathways go up in ______ tracts
myleinated
Sensory neurons of PNS had their cell bodies in
DRG
Neurons of somatorsentory innervate where
neck and below
type of cell boy of DRG
pseudounipolar
Mechanoreceptors, thermoreceptors, nocireceptors are what type of sensory receptor
Exteroreceptive
Proprireceptirve sensory receptors deal with
muscle lenght, tension
Visceral afferents that localize pain and sensation poorly are part of
Interoreceptive category
Area in periphery where an adequte stim cauases a respone
receptive field
How does Pancinian corpuscle work
detects vibration–> activate ion chans–>generates AP
frequency of action potential firing per neuron
Rate code
number of neurons firing–> info sent to sp cd and summated together
Spatial summation Code
Action potential speed
conduction velociy
A-alpha and A beta are
large myleinated finbers
Abetta fibers for
skin: light touch, vibration, pressure
Thin myelinated fiber A delta have____ ocnduction
medium conduction
Fast pain cooling receptors (nocirecpetors) are
A delta fibers
Unmyelinated C fibers are
slow
nocireceptors (slow pain); warm recpetors are
unmyelinated C fibers
Compound Action potential is clinical diagnostic tool for
recordig whole peripheral nerve
Compound AP potential tool determines
is axon is missing, damaged or demyelinated
to things that determine sensitivity and function of skin nerve endinds
location: superfiical or deep
ending; capsulated or non-capsulated
sustained unchanging stimulus , from pressure or shapes of objects
Slowly adapting
Resposne to changing stimulus, such as impact, motion of objects
Rapidly adapting
what does spatial resolution depend on
Receptive field size of each neuron and innervation density
sensitive areas are usually:
high density of receptors
small size recepive fields
mechanoreceptors have
____ threshold
______respond to pain
________ unless stimulated
low
don’t
silent
These guys are great for fine touch, 2 pt discrimination
Merkels disk
how are merkels discs innervated
1 axon per several disks
Merkel discs are _______ adapting response
slowly
what is the receptive field for merkels disc
several, small sensitive touch domes
high density of these in the finger tips, lips and mouth
merkel discs
Great for sharp resolution of texture, surface of objects like bumpy vs braile
merkels discs
Good for 2 pt and sensing change in edges, bumps and corners of objects
Meissners corpuscles
these are in glabrous skin only
meissners corpuslces
what is the receptive field for meissners corpuslces
single spot
Meisnners corpuscles found in high densitiy in:
finger tips, lips and mouth
These guys enclose stacks of schwann cells
meissners corpuscles
good for sensing edges/corners and bumps to lift and release objects
Meissners corpuscles (superficial)
merkels disk are superficial or deep
superficial
the receptive field for meissners corpuslcles
single spot
for Meissners corpuscles, the # of AP’s fired it
times skin indented
Meissners are slow or rapid adapting
rapid
these guys sense streth of skin and sense gravity force against skin
Ruffiini corpuscles
ruffini corpuslces located
deep in dermis
Receptive filed for Ruffini corpuscles are
large and diffuse
stretch of skin sensed by
ruffini corpuscles
good for sense of gravity force against skin
ruffinnii corpuslces
what’s the receptive field like for ruffinni corpuscles
large and diffuse
Ruffinni corpuslces axons do this
surround collagen fibils
Ruffini use what type of fiber
Abetta slow adaptors
this stretches skin and dertermines what you graspoed
ruffinni
pancinian corpuscles are superficial or deep
deep
extremely sensitive, good at detectin high frequency
panciana corpuscles
receptive field for pancian corpuslces
very large and diffuse
large fluid filled capsule wrapped around bare nerve ending, capsule filters out sustained stimulil
pancinian
pancianan is rapid/slow adapting
rapid
Receptive field has axons wrapped around base of follicle
hair follcle receptor
Hair follicle receptors are rapid or slow adaptigin
rapid
Hair fibers can be
Abetta or A gamma
these two do good job of endocing spacing of dots (braille)
merkels and meissners bc good as detecting texture
Can pancinaian determine spacing of dots well
no
overall pic in brain d/t sum of info from pattern of actviation of dif fibers
spatial summation code
thermoreceptors and nocireceptors have what type of nerve endins
free nerve endings
encodes skin temp for warming and coling
thermoreceptors
fire AP at continous slow rate at normal skin temp
Thermoreceptors
Cooling receptors _______ rate when skin is cooled
increase
When skin is warmed, cooling receptors
stop firing
Type of nerve ending for cool receptors
free nerve ending, thinly myelinated (A-delta)
Receptive field for cooling receptors
very small and infrequent
When skin is warmed, warming receptores
increase firing rate
when skin is cooled, warming receptors
stop firing
Nerve ending of warming receptors
free nerve ending, unmyelated
type of nerve for warming receptor
unmyleainate C fiber
respond to stimuli that damage or threaten to damage tissue
nociceptors
nociceptors make up
70% of all sensory neurons
tooth pulp and cornea made up of
nociceptors
A mechanoreceptosr are
nocireceptors
these respond to intense force or heat
A mechanoreceptors
A mechanoreceptor type is:
Adelta, axon unmyelinated and free nerve endins
Nerve endins on A mecanoreceptors:
RF on A Mechanoreceptor
Slowly/quickly adapting
free
small RF
slowly adapting
Fast pain: sharp, shooting, electrical pricking pain and easy to localize pain
A mechanonociceptors
immediate pain when you stub toe, hit thumb, hand under hot waer
a mechanoreceptors
If you get pinched, what type of adapting response do you get
slowly adapting with an on/off switch
These guys sense intense force and high heat
C polymodal nociceptors
C polymodal chemicals are:
bradykinin, prostaglandins and histamine
Axon in C polymodal is myelinated/unmyelinated
unmylinated
C polymodal nociceptors are slowly or rapidly adapting
slowly
nociceptor for long-lasting, burning, aching pain thats hard to localize
C polymodal nociceptors
pinch, zing, quick toe stub activates
A-mechanoreceptors
