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44 terms

Viscerosomatic Sensation 1

Principal sensations
Touch (Mechanosensation and Thermosensation), Prorioception, Nociception
Activation of peripheral receptor results in a generator potential
Graded response, Sums to reach threshold and fire an action potential, Conversion of peripheral stimuli (mechanical or heat) to electrical current
Nerve fiber that's not myleinated
C (axons in Group IV)
Cutaneous mechanical receptors can detect what types of stimuli
Location, intensity and duration
Mechanoreceptors (encapsulated) types
Slowly adapting (SA) - I, Slowly adapting (SA) - II, Fast adapting (FA) - I, Fast adapting (FA) - II
Respond to warming and cooling
Thermoreceptors are spontaneously active at
normal tempuratures
Thermoreceptors have _____ receptive fields
Spot-like (1 mm diameter)
Proprioceptors Sense
joint position in space
Proprioceptors Important for
normal coordinated movement
Muscle Spindles Type Ia responds to
dynamic, rate of change
Muscle Spindles Type II responds to
static, muscle length
Muscle Spindles Excite
alpha motor neuron
Muscle Spindles Increase
muscle tension
Golgi Tendon Organs are type
Ib sense stretch on tendon (muscle contraction)
Golgi Tendon organs Inhibit
alpha motor neuron
Golgi tendon organs are involved in Compliance which is
"give of muscle"
Nociceptors respond when there is
Damage/threatened damage to skin
Principal nociceptors
Aδ- mechanonociceptors, C polymodal nociceptors, Silent (sleeping) nociceptors
Defining characteristic of nociceptors
they sensitize, this is unique to nociceptors and means that the rate of firing increases after injury
Joint Nociceptors are found in
Joint capsule and ligaments
Joint Nociceptors include
Group III (Aδ) and group IV (C) axons
Muscle Nociceptors are found in
Connective tissue surrounding joint
Muscle nociceptors are involved in
Aching and cramping
Muscle nociceptors include
Group III (Aδ) and group IV (C) axons
Silent Nociceptors
Do not respond to noxious mechanical/thermal stimuli before injury, After tissue injury, begin to respond to mechanical/thermal stimuli
Where are silent nociceptors Found?
in cutaneous, joint, and visceral tissues
Visceral Receptors Sensations
discomfort and pain
Visceral receptor types
Chemoreceptors, Mechanoreceptors, Thermoreceptors
Microneurography Used to
record and stimulate nerves in human subjects
Microneurography helps us Understand
sensations related to specific receptors
FA I (Meissner's corpuscle) sense
Tapping at 1 Hz, flutter at 10 Hz and vibration at 50 Hz
FA II (Pacinian corpuscle) sense
Tickle/vibration over 20-50 Hz
SA I (Merkel's disk) sense
Sustained pressure over 5 - 10 Hz
SA II (Ruffini endings) sense
No sensation
Aδ mechanical nociceptors sense
Sharp pain
C polymodal receptors sense
Dull, burning pain or itch
Muscle nociceptor (Group IV) sense
Cramping pain
Touch-pressure receptor, spinal termination, major ascending pathway
SA I receptor, hair follicle, Lamina III-IV, Dorsal columns
Flutter-vibration receptor, spinal termination, major ascending pathway
FA I receptor, FA II, hair follicle, Lamina III-IV, Dorsal columns
Proprioception receptor, spinal termination, major ascending pathway
Muscle spindle, Golgi Tendon, Type II join, Lamina IV-VII, X, Dorsal columns
Cold receptor, spinal termination, major ascending pathway
Aδ and C receptors, Lamina I, II, V, STT*
Warm receptor, spinal termination, major ascending pathway
C, Lamina I, II, V, STT
Aδ/ Group III, and C/ Group IV receptors, Lamina I, II, V, X, STT (and others)**