Dental Neuroscience 2

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  1. Mechanoreceptor functions:
    Vibration, pressure, stretch, and associated with hair
  2. Mechanoreceptor fibers
    A beta and some A delta
  3. True or False: Thermal receptors include both sensation and pain.
    False. Thermal receptors are only sensation, NOT pain.
  4. Thermal receptor heat ranges:
    • Hot: 34-40 degrees C
    • Cold: 15-30 degrees C
  5. Miller's Law of Specific Nerve Energies
    Receptors are responsive to one type of energy
  6. A beta fibers include Encapsulated endings and endings with accessory structures like:
    Meissner corpuscles, Merkel endings, muscle spindle secondary endings, etc
  7. A-delta fibers innervate:
    • Some nociceptors (sharp pain)
    • Cold receptors
    • Most hair receptors
    • Some visceral receptors
  8. C fibers innervate:
    • Most nociceptors (dull, aching pain)
    • Warmth receptors
    • Itch receptors
    • Some (few) mechanoreceptors
    • Some visceral receptors
    • Postganglionic autonomic efferents
  9. Noxious sensations involve
  10. Structure of skin:
    • Epidermis: layers of epithelial cells
    • Dermis: CT
    • Basal membrane: regenerative capacity
  11. Endings around hairs located ________. Receptor ending is: _________. Adaptation is _______. Function is _______.
    • Hairy skin in dermis
    • Nerve terminal spiral wrapped around root of hair
    • Rapid
    • Hair movement
  12. Merkel endings are located in __________. There are ____ Merkel cells for every 1 nerve terminal. Receptor endings are found in cells with ________. _________ adapting. Functions are _________.
    • All skins - in deep epidermis about basal membrane
    • 5-10
    • Cell with no elastic structures
    • Slowly
    • Light pressure, not much known
  13. Free nerve endings are located in ________. Receptor endings for unmylinated nerves end in ________ fibers. Also endings in ____ fibers. _______ fibers are rapidly adapting. _____ fibers are slowly adapting. Functions are: _________.
    • Epidermis
    • A and B fibers
    • C
    • A and B
    • C
    • Thermal and pain, some are mechanical
  14. Receptive Field (RF)
    Every mechanoreceptor has a particular area in the periphery where adequate mechanical stimulation produces the response of a single mechanoreceptor.
  15. A beta fibers
    • Most common
    • Myelinated
    • 6-12 microns in diameter
    • 30-70 m/s
    • Receptors are all mechanoreceptors except a small portion of free nerve endings
  16. A delta fibers:
    • Thin myelinated
    • 1-6 microns in diameter
    • 5-30m/s
    • Receptors are free nerve endings
  17. C fibers
    • Unmyelinated
    • Less than 1.5 microns
    • .5-2 m/s
    • Receptors are free nerve endings
  18. Central terminals of afferent fibers pass to the ___________ part of the spinal cord through ______ columns in the brainstem.
    • Ipsilateral
    • Dorsal
  19. Fasciculus gracilis
    • Dorsal column
    • Central terminal goes up to the brainstem
  20. Fasciculus cuneatus
    Cervical segments
  21. At each successive spinal level, fibers entering the posterior column add on _______ to those already present.
  22. Nucleus gracilis and nucleus cuneatus are __________. Fasciculus gracilis and fasciculus cuneatus are __________.
    • Contralateral
    • Ipsilateral
  23. Third order neurons go from _____ to __________.
    Thalamus to Cortex
  24. Information from head goes to:
    • VPM

    • Then they get relayed as sensory information to S1
  25. Information from body goes to:

    Then gets relayed as sensory information to S1
  26. VPL is called relay nucleus because it gets input from ____ and _______. It also sends output to the cerebral cortex.
    • Nucleus Gracilus
    • Nucleus Cuneatus
  27. VPM is important for __________.
    Pain transmission for head, neck, and mouth.
  28. 3rd order neurons in VPL raise their axons to:
    Primary Somatosensory Area (S1) of cerebral cortex
  29. Input to _______ comes from S1 and may play a role in _________.
    • S2
    • Forming tactile memories
  30. In somatotropic mapping, information from face takes a significant portion of the _______ part of the somatosensory cortex.
  31. In somatotropic mapping, the body input can be found in the more _______ aspect of the somatosensory cortex.
  32. Objective signs of nociception include:
    • Increased BP
    • Increased Respiration
    • Electrophysiology
  33. Analgesia
    Absence of pain
  34. Anasthesia
    Absence of all sensation
  35. A and C fibers are responsive to:
    • Mechanical on skin
    • Heat >45 degrees C
    • Cold < 20 degrees C
    • Algesic chemicals
  36. Transmitters of nociception are:
    • Substance P
    • Glutamate
  37. As you increase the stimulus temperature, you ______ the frequency of action potentials.
  38. Hyperalgesia function
    To protect from touching the site of injury
  39. Efferent function of nociceptors:
    Pathways that cause vasoconstriction
  40. Low threshold input from:
    Mechanoreceptors only
  41. Wide dynamic from:
    Mechanoreceptors and nociceptors
  42. High threshold from:
    Nociceptors only
  43. Lateral STT
    Location, intensity, and quality of pain
  44. Medial STT
    Emotional reaction to pain
  45. STT neurons can become sensitized after injury or inflammation. This is the physiological correlate of:
  46. Spinoreticular tract function:
  47. Spinohypothalamic tract function:
    Autonomic reaction to pain (HR, BP, Respiration)
  48. Spinomesencephalic tract function:
    • To periacqueducatl gray (PAG).
    • Inhibiting/modulating pain. --> decreases activity of descending neurons
  49. Descening modulation of pain: Endogenous - PAG--> DRM --> Spinal cord
    • Inhibit or modulate pain and activity of STT neurons
    • Analgesia works on this system through opiates
  50. Opiates ____ the release of _______ from nociceptor, which decreases excitability of the STT.
    • Decrease
    • Substance P
  51. In demo, 1st sense lost was:
    2nd sense lost was:
    3rd rxn was:
    • light touch
    • Pricking; and cold changed to hot
    • Pricking changed to burning
  52. Dimensinos of the pain experience
    • 1) Sensory discriminitive - Quality, intensity, duration, location - Lateral STT
    • 2) Motivation/Affective - Emotinoal response, Medial STT
    • 3) Cognitive/Evaluative
  53. What causes cold induced burning pain during blockade of A-fiber (myelinated) conduction?
    Remaining function of C fibers in limb
  54. Which type of receptor is not found on the face?
    Pacinian - unable to detect vibration
  55. Specialized tissues of the face have what type of receptor endings?
    Free nerve endings only
  56. How many neurons per ganglion in TRG vs DRG
    100k vs 35k
  57. What is the somatotropic organization of trigeminal?
    • V1- medial
    • V2 - Mid
    • V3 - lateral
  58. Fiber composition of TG vs Spinal cord
    • 70:30 of A-delta to C in TG
    • 20:80 in spinal cord
  59. Differences of TG from SC and CNS
    • 1) Fiber composition
    • 2) TG projects to multiple levels of brainstem - spinal nerves project to contiguous spinal segments
    • 3) TG project directly to autonomic relay nuclei in brainstem; no spinal equivalent
  60. Vp involved in
    Dental pain
  61. Vp (Principal) consists of _____ fibers. Functions:________.
    • A-beta/A-delta
    • Touch, proprioception, dental pain
    • Output to thalamus is bilateral
  62. Vo - Subnucleus oralis for:
    • Oral reflexes (jaw closing)
    • Bilateral projections: Vmo, cerebellum
  63. Vi - subnucleus interpolaris
    • Multifunction - touch, pain
    • Crossed projections: thalamus, cerebellum
  64. Vc - subnucelus caudalis
    • Multifunction (touch, pain, reflexes)
    • C fiber input
    • Laminar organization (looks like spinal cord)
    • Crossed projections: thalamus, NTS
  65. Stomatotropy
    • "Inverted face"
    • Most medial of face is most lateral of brainstem
    • V1 is ventrolateral
    • V3 is dorsomedial
  66. Nearly all C fibers terminate in
  67. Touch pathway is mostly __ receptors (2)
    • A-beta and A-delta
    • Uses Vp>Vc
    • Bilateral Vp to thalamus/cortex (medial lemniscus and dorsal trigeminal trunk)
    • Crossed Vi and Vc project to thalamus/cortex (medial lemniscus only)
    • Cells that respond to touch are in caudalis
  68. Extraoral thermal and pain pathways:
    • Mostly A-delta and C fibers
    • Vc>Vi>>>Vo=Vp
    • Crossed Vc and Vi project to thalamus/cortex (ML and TGTT)
  69. What pathway does extraoral pain follow?
    Trigeminal nucleus
  70. Intraoral thermal and pain pathways:
    • A delta and C fibers
    • Vp=Vc>Vi>Vo
    • Bilateral projections from Vp and Vc to thalamus/cortex
  71. What pathways are important for passing of pain inside the mouth?
    Caudalis and Principalis (Vc and Vp)
  72. Intraoral pain pathway is a redundant system - True or False
    True - Vc and Vp
  73. What % of the primary sensory cortex is taken up by trigeminal innervated nerves?
  74. What is the most important pathway of pain outside the mouth?
    Caudalis (contralateral projection pathway)
  75. Skeletal muscle reflexes (2)
    • Jaw opening/closing
    • Blinking
  76. Autonomic reflexes controlled by trigeminal (3)
    • Lacrimation
    • Salivary secretion
    • Cardiac (O2 sparing, diving reflex, ocular reflex)
  77. Jaw Muscle Reflexes
    • Vmes (Primary afferent inside CNS)
    • Proprioceptive reflex- monosynaptic via Vmes and Vmo
    • A-beta and A-alpha fibers
    • Bilateral Vmes and TRG inputs to Vmo
    • Vmo - origin of alpha motoneurons for jaw muscles
    • Modulation via Vc (pain)
  78. Cornea (Blinking) Reflexes
    TRG input - Vi - Facial motor nucleus - to alpha motoneurons
  79. Major points of muscle reflexes:
    • Use sensory neurons inside brain
    • Monosynaptic, fast, bilateral - generates motor neuron output on both sides of brain
    • Facial nerve controls muscle contraction
    • Reflex modified by pain input (diminish in intensity) and voluntary control
  80. Trigeminal - Parasympathetic
    • 2nd order neurons in TBNC or via NTS
    • Transmitters: to post ganglion is Ach; post ganglion to tissues is Ach and NO
    • Overdeveloped system
    • 3 sources of preganglionic neurons (Edinger-Westphal, Superior salivary, Inferior salivary)
    • Inputs of TG go directly to NTS
    • Involved in dilution of migranes
  81. Where do TG sympathetics go?
    All of the face - superior cervical ganglion
  82. Trigeminal - Sympathetic
    Spinal IML -->(Ach) Superior cervical -->(NE) All orofacial tissues
  83. Classification of Craniofacial Pain
    • Neuralgic/vascular - 10% - Trigeminal neuralgia, migraines
    • Muscle/joint/soft tissue (TMJ, burning mouth) - 23%
    • Dental/alveolar (Pulpitis, sinusitis, dry socket) - 30%
    • Idiopathic (referred) - 37%
  84. Inside and outside of tooth innervated by sympathetics - True or False
  85. TRG innervates (in mouth)
    Pulp, dentinal tubules, PDL, gingival
  86. Vmes innervates (in mouth)
  87. Sympathetic postganglionic fibers innervate (in mouth)
    Pulp cavity blood vessels
  88. TRG neurons detect:
    • changes in pressure, temp, and signal pain in oral cavity
    • Some located mid root
    • More located at root apex
  89. Vmes neurons in mouth detect:
    • changes in position, feedback for bite force
    • Incisors> Molars
    • None located mid root
    • High density around root apex
  90. Interior tooth innervation
    • Pulp/dentin from TRG
    • Nerve density: Crown> root
    • Sensory convergence: 1 tooth supplied by 150 TRGs
    • Sensory divergence: 1 TRG supplies 1-5 teeth
    • Tissue divergence: Some TRGs supply pulp, PDL, and or gingival tissues
  91. Interior tooth innervation -
    A delta fibers from TRG supply:
    C fibers from TRG supply:
    • Dentinal tubules and pulp cavity
    • Pulp cavity only
  92. What is movement within tubules sufficient for?
    A delta fiber excitement = sharp pain
  93. What is responsible for transmitting pain?
    A delta fibers receiving thermal activity input - significant because no other part of body has this
  94. How is oral persistent pain transmitted?
    C fibers responsible for aching pain
  95. Mechanisms for acute dental pain
    • Hydrodynamic theory: A delta fibers only
    • Receptor specific direct: A delta fibers
  96. What is the caveat to signaling?
    Inflammation - no way to discern A delta or C fiber sensitization
  97. Inputs from ____ distribute throughout entire length of trigeminal nucleus
    Single tooth
  98. Areas that receive input from teeth receive input from other oral tissues. This is a reason for what?
    Referred pain.
  99. Peripheral features that limit tooth pain localization:
    • Multiple teeth supplied by 1 TRG neuron
    • Multiple tissues supplied by 1 TRG neuron
    • Multiple TRG neurons supply each tooth
  100. CNS featurse that limit tooth pain localization:
    • TRGs from 1 tooth project to multiple brainstem regions
    • Secondary brainstem neurons excited by >1 tooth
    • Enlarged bilateral cerebral cortical representation
  101. Normal disc position in the intermediate zone vs. persistent disc displacement
    • Normal: disc between articular eminence and condyle
    • PDD: Disc anterior to condylar head
  102. Diagnostic Criteria for Myofacial Pain
    • If pain is affected by jaw movement, function or parafunction then pt hx is indicative
    • Palpitation results in familiar pain at temporalis or masseter
    • Opening results in familiar pain from maximum unassisted/assisted movement
    • S/S is 84/95
  103. Normal TMJ Findings
    • History - None
    • Exam - No TMJ noise
    • Active opening >40mm
    • Lateral movement >7 mm
    • No pain with range of motion of jaw
    • Imaging - no positive finding
  104. Criteria for Myofacial Pain with Referral
    • Palpitation results in report of familiar pain at temporalis and masseter muscles AND
    • Report of pain at a site beyond the boundary of the muscles being palpitated
    • S/S is 85/98
  105. Where does masseter muscle pain refer to?
    Tooth pain
  106. How does masseter referred pain to teeth feel?
    Dull, achy, and moves around
  107. Combining diagnostic criteria for myofascial pain and myofascial pain with referral increases S/S
    True - 90/100
  108. Diagnostic criteria for Arthralgia/arthritis
    • Palpitation of any joint site results in familiar joint pain - around lateral pole
    • OR range of motion results in familiar joint pain with max assisted/unassisted or lateral/protrusive movement
    • S/S is 91/96
  109. Headache attributed to TMD - Diagnostic Criteria
    • Headache of any type
    • Pain related TMD demonstrated by clinically based diagnostic criteria
    • Headache has characteristics typical of pain related TMD
    • Hx is report of headache in temple that is changed with jaw movement, function or parafunction AND
    • Exam finds familiar headache with palpitation of temporalis muscle or max unassisted/assisted, lateral/protrusive movements
    • Headache is not better accounted for by another headache diagnosis
    • S/S is 89/97 - not good enough
  110. Target for sensitivity and specificity is:
  111. Diagnostic Criteria for TMJ disc displacement with reduction
    • In closed mouth, posterior band is located in 11:30 clock position
    • Intermediate zone of disc is anterior to condyle
    • Hx is positive for
    • Noise in the past month and click associated with jaw motion 1/3 of time
    • S/S is 33/94
    • Bad sensitivity because a lot of people with displaced discs don't have noise
  112. Diagnostic criteria for disc displacement with reduction with intermittent limited opening
    • Hx is positive for both of following:
    • Any noise present and jaw lock or catch
    • Same exam as specified for disc displacement with reduction
    • S/S is 46/97
  113. Both types of disc displacement diagnoses need a ____ for better sensitivity
  114. Diagnostic Criteria for Disc Displacement without reduction (closed lock)
    • PDD
    • Jaw lock or catch so that it wouldn't open all the way and
    • limitation in jaw opening severe enough to limit mouth opening to interefere with ability to eat
    • In exam, max assisted opening <40mm
    • S/S is 80/97
  115. Disc displacement without reduction without limited opening
    • Hx same as for limited opening
    • On exam, max assisted opening >40mm
    • S/S is 54/79
    • Hard to determine even with MRI
  116. Degenerative Joint Disease
    • Osteoarthrosis (painfree)
    • Osteoarthritis (pain)
    • Hx is positive for any noise in past month AND
    • Exam is positive for either crepitus detected with palpation during max or lateral or protrusive
    • OR patient report crunching, grinding, or grating noises during exam
    • Disease can cause malocclusions - especially anterior open bites
    • Imaging shows severe subchondral sclerosis with surface flattening, generalized sclerosis, subchondral cysts, ostophytic formation and/or erosion
    • S/S is 49/86
  117. What is basic definition of Degenerative Joint Disease
    Breakdown of bone beneath
  118. TMJ Dislocation
    • Hx + for report of jaw locking in wide open mouth position AND
    • Inability to close the mouth without specific manipulative manner
    • Exam + for inability to return to normal mouth position unassisted
    • S/S is 98/100 (for subluxation only)
  119. Trigeminal Neuralgia
    • 4 out of 100,000 people
    • Onset later in life
    • 2x more prevalent in women
    • Almost always unilateral
    • Mostly in V2 and V3
    • Headache is quick and pain has sudden onset of pain
  120. Deafferentiation Pain
    • Arising from alterations or injury
    • Typically continuous burning pain (can be phantom limb)
    • Dentists by far perform the most deafferentiation surgery of any health professionals with extractions and root canals
Card Set:
Dental Neuroscience 2
2012-03-06 13:27:35
Dental Neuroscience

For Exam 2
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