Resting Membrane Potential and Local Potential

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Resting Membrane Potential and Local Potential
2012-07-17 02:45:45
Resting Membrane Potential Local

Resting Membrane Potential and Local Potential
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  1. major cation inside
  2. major cation outside
  3. major anion inside
  4. major anion outside
  5. excess of positive charges outside and negative charges inside the membrane; gives rise to an electrical potential difference which ranges from about 60 - 70 mV
    resting membrane potential
  6. type of channel that opens when the membrane potential changes beyond a treshold value
    voltage-gated ion channel
  7. opens when bound by a specific agonist, initiates depolarization or hyperpolarization of the plasma membrane
    ligand gated
  8. RMP of nerve cells
  9. RMP of muscle cells
  10. chemical gradient = electrical potential gradient. potential level across the membrane that exactly opposes net diffusion. allows theoretical membrane potential toe calculated for particular ion
    Nernst Equation
  11. membrane potential results from all the ions that can cross the membrane
    goldman-hodgkin-katz equation
  12. stimulate ion channels sensitive to either voltage or pressure but does not produce an action potential
    subtreshold stimulus
  13. can be summated algebraically
    subtreshold stimulus
  14. not propagated along the nerve
    subthreshold stimulus
  15. potentials that decrease in strength as they spread out from the point
    graded potentials
  16. are graded, can increase, temporary, not propagated and cannot reach threshold
    local potential
  17. membrane becomes permeable to sodium ions overshoots beyond zero and becomes somewhat positive
  18. sodium ion channels close; potassium open more
  19. membrane potential becomes more negative than the original resting membrane potential
  20. travel away from the stimulus; all-or-nothing principle
    action potentials
  21. slow channels and responsible for the plataeu portion of action potential
    voltage activated calcium-sodium channel
  22. fast channels that is responsible for the spike portion of action potential
    voltage activated sodium channels
  23. excessive flow of potassium; carries tremendous numbers of (+) charges to the outside creating more(-) inside
  24. jump of action potential from node to node; increased velocity of nerve transmission
    saltatory conduction
  25. process of eliciting action potential
  26. stimulus does disturb the membrane potential locally for as long as 1 ms but not sufficient to activate the automatic regenerative processes of the AP
    acute subtreshold potential
  27. local potential changes
    acute local potential
  28. after an action potential; new stimulus can't be elicited because sodium channels are inactivated
    refractory period
  29. period in which 2nd AP cannot be elicited even with a strong stimulus
    absolute refractory period
  30. stronger than normal stimuli can excite the fiber because potassium channels are open; sodium channels still have not been reversed from inactivation state
    relative refractory period