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70 Cards in this Set

  • Front
  • Back
Posterior column-medial lemniscus system
discriminative touch, vibratory sense, conscious proprioception from body
Anterolateral system (ALS)
pain, temp, crude touch from body
Trigeminal pathway
all types of somatosensation from face
Spinocerebellar pathways
non-conscious proprioceptive info to cerebellum
Receptive fields
the area of skin innervated by all of the branches of a single primary afferent nerve fiber
Size of receptive fields
inversely related to innervation density
2-point discrimination
areas with large receptive fields have less discriminative ability (greater discrimination thresholds)
proprioceptors
located in muscles, tendons, joint capsules:
muscle spindles, golgi tendon organs, joint receptors
Nociceptors
are all free nerve endings
Thermonociceptors
extreme levels of hot or cold
Capsaicin
active ingredient in hot peppers
receptor (TRPV-1) activated by high temp.
topical analgesic: decrease responsiveness to receptors (also anti-inflammatory)
Hyperalgesia
exaggerated response to stimulus
Sensory transduction
conversion of mechanical stimulus into electrical signal

exception: Merkel cells
Slowly adapting receptors
active throughout stimulus
signal unchanging stimuli (size and shape)
Rapidly adapting receptors
active at onset and removal of stimulus
signal changing stimuli (movement detection and direction)
axon reflex
release of NTs and nueropeptides (substance P) from sensory ending--> inflammatory response
primary hyperalgesia
allodynia
induction of pain by normally innocuous stimuli

central (secondary hyperalgesia)
neuropathic pain
chronic intense pain refractory to conventional analgesics

central (secondary hyperalgesia)
Primary Neuron
peripheral process with receptive ending
cell body: PRG
central processes: form fascicles gracilis & fasciculus cuneatus
synapse: caudal medulla
Secondary Neuron
cell body: nucleus gracilis/ nucleus cuneatus
axon decussates-- forms contralateral medial lemniscus
synapse: thalamus
Third Neuron
cell body: VPL of thalamus
axon: enter posterior limb of internal capsule
synapse: primary somatosensory cortex
Pseudounipolar morphology
large diameter, heavily myelinated, rapidly conducting fibers
Fasciculus gracilis
Primary neuron
below T6 dermatome
lower extremity, pelvis, abdomen, lower thorax
Fasciculus cuneatus
primary neuron
T6 and above
upper thorax, upper extremity, neck
Posterior spinal artery
cuneate fasciculus and gracile fasciculus
Anterior spinal artery
medial lemnicus of medulla
Primary somatosensory cortex:
3a
proprioceptive inputs
Primary somatosensory cortex: 3b, 1
cutaneous mechanoreceptors
Primary somatosensory cortex: 2
tactile and proprioceptive stimuli
Lesion of secondary cortical processing sites
astereognosis:
inability to identify objects by touch
area 3b lesions
deficits in all forms of tactile sensations mediated by cutaneous mechanoreceptors
area 1 lesions
inability to discriminate texture
area 2 lesions
inability to distinguish size and shape of objects
lesions of SI
eliminate SII responses
midline myelotomy
eliminates intractable pain
visceral pain pathway
Esthesia
refers to all types of sensation
paresthesia
an abnormal postiive sensation, such as burning, pricking, numbness, tingling
dysesthesia
unpleasant, abnormal sensations experienced in the absence of stimulation
hypesthesia
diminished sensitivity to stimulation
algesia
refers to a sense of pain
hyperalgesia
exaggerated response to a painful stimulus
hypalgesia
decreased sensitivity to pain
allodynia
pain resulting from stimuli that are normally innocuous
Neospinothalamic pathway
direct pathway fromm spinal cord to thalamus
well localized pain sensation
paleospinothalamic pathway
indirect pathway from spinal cord to a different thalamic nucleus
poorly localized pain sensation
A delta fibers
lightly myelinated
pseudounipolar
slowly conducting fibers
fast (hot, sharp) pain
C fibers
unmyelinated
slowest conducting
slow (dull, burning, aching) pain
A delta fibers
2-30 spots
smaller, more numerous than C fiber spots
non discriminative touch, innocuous thermal, nociceptive signals
C fibers
1-2 spots
larger, fewer than Adelta
noxious and innocuous mechanical, chemical, thermal signals
Lamina V neurons
likely substrate for referred pain (receive convergent nociceptive and non-nociceptive inputs
Dejerine-Roussy (Thalamic pain) syndrome
thalamic lesions resulting in severe, contralateral debilitating pain
cause not well understood
Periaqueductal gray
opiate receptors stimulated by ascending pain fibers
Nucleus raphe magnus
serotonergic neurons project to interneurons in posterior horn
Raphespinal fibers
enkephalin-containing interneurons exert pre- and postsynaptic inhibition of posterior horn neurons
gate control theory
non-nociceptive inputs to the posterior horn modulate rostral transmission of nociceptive signals via stimulation of inhibitory interneurons
rostrocaudal "onion skin" pattern of facial pain
perioral regions represented rostrally, posterior and lateral face represented caudally
peripheral nerve lesion
all sensory modalities lost distal to lesion usually includes motor deficits
spinal nerve lesion
all sensory modalitites lost throughout dermatome
motor deficits will be present as well
posterior root lesion (radiculopathy)
all sensory modalities lost in dermatome
no motor deficits
Syringomyelia
bilateral loss of pain and temperature sensation in the affected dermatomes
Posterior cord syndrome
I/L loss of discriminative touch sensation and proprioception at and below level of lesion
Anterior cord syndrome
C/L loss of pain and temp sensation beginning 1-2 segments below level of lesion, loss of sensation may not be complete (dual blood supply to ALS)
Ectoderm
CNS, PNS, epidermis, CT of head
Mesoderm
muscle tissues, CT, blood vessels, viscera
Endoderm
epithelium of GI tract, respiratory system, urinary bladder
Mesenchyme
CT and muscle tissues
surface ectoderm
Lens, epithelium of cornea, conjunctiva, lacrimal gland
neural ectoderm
vitreous body, epithelium of retina, iris, ciliary body
sphincter pupillae and dilator pupillae muscles, optic nerve
neural crest
sclera, stroma of cornea, ciliary body, iris, choroid
mesoderm
extraocular muscles, eyelids, hyaloid system, coverings of optic nerve, CT and blood vessels of eye, bony orbit, vitreous body