Week 3 Somatosensory Flashcards
General senses- dorsal columns
light touch, pressure, vibration, proprioception
Light touch-tactile sense
2 point sense; stereognosis- identify object w/out seeing it; graphesthesia-recognize writing on hand w/out seeing it
Proprioception
limb position- awareness of position of skeletal parts of body
motion sense- awareness of active or passive movement
Pain- spinothalamic tract
Nociception- detection of tissue trauma-produces spinal reflexes, sympathetic reflexes & stress responses- never conscious- greater than or equal to 45 degress C
pain- phenomenon of conciousness w/ emotional & congnitive features
A-alpha- I
limb position & motion- heavily myelinated- fast; dorsal column
A-beta- II
low threshold stimuli; gentle touch; vibration & 2 point discrimination; myelinated; slower than A-alpha; dorsal column
A-delta- III
First-fast pain; lightly myelinated, bright and localized pain; sets off protective relexes; “the pinprick hurt” more specific; spinal thalamic tract
C fibers- IV
second-slow pain,warmth; unmyelinated; smaller than A-delta; poorly localized-long pain, dull, aching “my hand hurts”; triggers disuse of injured site-healing; spinal thalamic
C fibers- IV
second-slow pain,warmth; unmyelinated; smaller than A-delta; poorly localized-long pain, dull, aching “my hand hurts”; triggers disuse of injured site-healing; spinal thalamic
Merkel cells
2 pt discrimination
Pacinian corpuscles
vibration
Meisner
shape/surface texture
Free nerve endings-thermo
cold or warmth (gentle changes)
Lamina I
nociceptive specific neurons; 2nd order neurons relay incoming pain to thalamus via spinothalamic tract
Lamina II
interneurons for pain modulation- act locally
