1. local anesthtics can reversibly block generation and propagation of nerve impulses in ALL excitable cells.
    True, any sodium channel may be blocked
  2. gate control theory
    rub your arm after stubbing toe
  3. Is pain an unpleasant sensory AND emotional experience with actual or POTENTIAL tissue damage
  4. what are the two aspects of pain?
    sensory and affective(escape threshold-varies, reaction, variable, unpleasnatness)
  5. what are the processes (4) involved in pain experience?
    transduction, transmission, modulation, perception.
  6. transduction
    physical to electrical
  7. transmission
    peripeheral to CNS
  8. modulation
    attentutaiton of pain info
  9. perception
    actual pain experience
  10. nociception
    potentially tissue damaging thermal or mechanical energy on Adelta or C fiber nerve endings.
  11. pain from the head
    do not go through spinal cord, jus thte trigemeinal nerve
  12. what nerve does local anesthesia hit?
    nerve endings at the local site the lower neuron before it crosses over.
  13. head pain 
    diff b/t facial and trigeminal
    pain in different areas of the head
  14. trigeminal nuclei
    • main sensory info- sensory nucleus
    • pain info- spinal nucleus caudalis
    • proprioceptive info- mesencephalic nucleus
  15. somatotropic info from dermatomes
    slide 19, area 1 mouth at the first segment
  16. what segment is not innvervated by CN V
  17. types of LA
    • topical
    • infiltration-injected into an area to be treated
    • regional nerve block- injected close proximity to nerve supplying the area to be anesthesized
  18. spinal LA
    injected in CSF in lumbar subarachnoid space (sugery of lower body)
  19. epidural
    injected into epidural space, spinal anestheisa but less likely to accidently rise to high segment
  20. intravenous LA
    injected into venous system of a limb, distal to point of circulation, DISTAL to the point of ciculation
  21. sympath block
    tratment of pain cause of reflec symp dystrophies for intractable pain (carminoma of pancrease or upper abdomen)
  22. symp bloackade
    • stellate gangion- upper arm, head, neck
    • celiac pleus- pancreas pain
    • lumbar symp- lower legs
  23. what receives signals
  24. are myelin sheaths in periphery called
    schwann cells
  25. what is the membrane that surrounds nerves?
  26. oligodnedrocytes in CNS surround/....
    more than one axon is wrapped
  27. which peripheral fibers to nerves are fast?
    • larger the diameter Aaphla¬†
    • alpha delta
    • c fibers are the slowest smallers diameter (1 m.sec)

    C is unmyelinated (dull throbbing pain)
  28. peripheral nerves are mixed with diff types of fibers
  29. voltaged gated channels depend on the membrane potentia. What are the three diff states?
    closed, open, inactive
  30. what is the structure of local anesthetic?
    lipophillic, amlide/ester, hydrophillic
  31. what form crosses the membrane and what form blocks the sodium channel?
    non-ionized and ionized
  32. How do LA work on blocking impulse conduction
    • inhibit sodium channel
    • decrease rate and degree of depolarization
    • failure to achieve action potential
  33. LA are weak bases pKa>7.4. What does onset depend on?
    pKa 50% of drug is ionized and only the nonionized form crosses into the nerve membrane
  34. which has a faster onset? Lidocaine or bupivacane
    • Lidocane because lower pKa
    • acidic tissue b/c of bacterial infection has slow entry into membrane
  35. what doe anestheitc potency depend on?
    lipid solubility. Higher solubility can use lower concentration
  36. what does duration of action depend on?
    protein binding
  37. what does clearnace depend on?
    • esters--hydrolysis via pseudocholineeserase
    • amides via hepatic enzymes
  38. are amides or esters more likely to be toxic?
    amides(but stable chemially and faster onset of action)
  39. LAs cause.....at local site.
    • vasodilation
    • washout related to bldflow
  40. vasoconstrictors are least effective when....
    high lipid soluble LAs
  41. LA effect on nerve fiber higher concentration for..
    • diameter
    • myelination
    • position (easier to get mantle fibbers)
    • Core fibers innervate distal nerves
  42. what sensations are lost first?
    • 1. pain/temp
    • 2. proprioception
    • 3. touch/pressure
    • 4. motor function
  43. during which phase are sodium channels converted from inactive to close?
    recovery phase
  44. rapid depolarization closes the....
    inactivation gate
  45. how many subunits does the sodium receptor channel have?
    4 alpha subunits
  46. inactivation gate is the
    pore is b/t
    • h gate
    • 5,6 subunit

    LA works on S6
  47. LA mode of action
    LA bind to Na channel, the h gate actually closes, trapping the anestheic inside the channel.
  48. LA possible mechanism
    close...open...inactivated via h gate closing
  49. LA will not inhibit permeability to Na.
  50. LA can cause elevation of threshold and sowing of spread of conduction. Only occurs at nodes in mylination
  51. What is 'critical length'?
    A critical length needs to be covered for the blockade to occur
  52. the smaller the nerve
    the easier to block.

    3 nodes of ranvier
  53. LA action can be increase by repeated stimulation of nerve fiber because
    • LA gaining more access to a binding site and having a greater affinity for it.
    • Known as "use-dependent block or phasic block'
  54. Xylidine derivatives(amides)
    • lidocaine
    • mepivacine
    • bupicanine
  55. Toluidine and Thiophene derviatives(amides)
    Prilocaine and atricane
  56. esters
    • procaine
    • chlorprocaine
    • tetracain
    • benocaine
    • cococain
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