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2011-01-29 16:03:06

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  1. What determines if Ach will act in an excitatory or inhibitory manner?
    • the type of ion channel on the post synaptic membrane
    • i.e
    • sodium--excitatory
    • chloride--inhibitory
  2. Source of Ach in the CNS?
    Nucleus Basalis
  3. Degeneration of Nucleus Basalis leads to/?
  4. What happens in Presynaptic Facilitation?
    nt decreases k+permeability, trapping k+inside the cell..effectively depolarizing the membrane so upon AP the membrane is dopolarized to +45 instead of +35
  5. Short-term memory is characterized by what?
    Presynaptic Ca +2
  6. What happens in presynaptic inhibition?
    Cl - permeability increased...hyperpolarizing the depolarization
  7. Ion channels are exclusively present where on the neuron?
    On the Axon
  8. What limits the frequency of AP?
    Absolute Refractory Period
  9. Post synaptic potentials are voltage or ligand gated?
    Ligand gated
  10. What nt is always excitatory in the CNS?
  11. Whats the difference between an Ionotropic and metabotropic nt receptor?
    • Ionotropic--nt binding opens an ion channel--quick
    • Metabotropic--nt binding activates a series of 2nd messengers which opens the ion channel..long activation..long duration
  12. Polio selectively affects what?
    LMN in Lamina 9
  13. What is the mode of action of a botulism toxin?
    B. toxin prevents release Ach from the presynaptic membrane
  14. A tumore in the cerebropontine angle affects what CN?
    CN VIII-vestibulocochlear
  15. Myesthenia Gravis?
    • Auto-immune--ab against Ach receptors...paralysis..
    • Diagnosis---Endrophonium(short acting- anticholinesterase
    • Treatment--Neostigmine(long lasting anticholinesterase)
  16. Whats the cure for Myesthenia Gravis?
    • Neostigmine
    • Anti-inflammatory
    • Immune-suppressant
    • Thymectomy
  17. What is the mode of action of Sarin Gas
  18. A lesion where would produce a toxic gait?
  19. A lesion in the midbrain region of the brainstem would produce what deficit?
    CN III lesion---can't adduct eye
  20. A lesion in the pons region of the brainstem would produce what deficit?
    Lesion of CN VI---can't abduct eye
  21. A lesion in the medulla region of the brainstem would produce what deficit?
    CN-XII---ipsilateral deviation of tounge
  22. Absolute refractory period is due to?
    Sodium inactivation
  23. What prevents the Action Potential from being bidirectional?
    Absolute refractory Period
  24. Hemosiderosis
    deposition of iron
  25. Hemochromatosis
    Disease caused by hemosiderosis