Ch10T11-19.txt

Card Set Information

Author:
aphy101
ID:
268204
Filename:
Ch10T11-19.txt
Updated:
2014-03-27 18:04:08
Tags:
profmwinston
Folders:

Description:
Ch 10 Topics 11-19
Show Answers:

Home > Flashcards > Print Preview

The flashcards below were created by user aphy101 on FreezingBlue Flashcards. What would you like to do?


  1. The potential difference across the cell membrane; is measured in millivolts.
    Membrane Potential
  2. The membrane potential of a resting neuron; has a value of -70 millivolts.
    Resting Potential
  3. The electrical voltage due to movement of ions across a membrane.
    Nernst Equilibrium (NE)
  4. What is the NE for Sodium ions (Na+)?
    +60 mv
  5. What is the NE for Potassium ions (K+)?
    -90 mv
  6. What is NE for Threshold?
    -55 mv
  7. What is NE for Membrane Resting Potential (MRP)?
    -70 mv
  8. At what membrane voltage do voltage gates open?
    -55 mv
  9. In order for Nernst to be reached, there must be what?
    Unimpeded Flow
  10. What will happen to the membrane voltage if the flow of an ion is reduced?
    The membrane voltage will go away from its Nernst
  11. What will happen to the membrane voltage if the flow of an ion is increased?
    The membrane voltage will go towards its Nernst
  12. The resting membrane starts out negatively charged, in what state?
    Polarized
  13. This actively transports sodium ions out of the cell and potassium ions into the cell and is largely responsible for the distribution of these ions across the membrane.
    Na+/K+ Pump
  14. What is the major intracellular positive ion?
    K+
  15. What is the major extracellular positive ion?
    Na+
  16. A mechanism that opens or closes based on chemical and electrical factors; the passage of potassium and sodium ions through a membrane depends on it.
    Gated Channel
  17. This opens at -55 mv for sodium to pass through the membrane.
    Na+ Gate
  18. This opens at -55 mv for potassium to pass through the membrane.
    K+ Gate
  19. Describe the location of sodium and potassium ions in resting membrane potential.
    Na+ is outside of the membrane, and K+ is inside (polarized state)
  20. How does the concentration gradient across the membrane affect whether ions go in or out of the membrane?
    Sodium and potassium diffuse along the concentration gradient from a region of high concentration to a region of lower concentration.
  21. When the membrane potential becomes more negative than the resting potential; decreases cell activity.
    Hyperpolarization
  22. When the membrane potential becomes less negative than the resting potential; increases cell activity.
    Hypopolarization
  23. Describe (using Nernst) 4 ways a resting membrane can be hyperpolarized.
    1) Increase the flow of K+ (making it closer to -90mv, thus more negative) 2) Reduce the flow of Na+ (making it further from 60mv, thus more negative) 3) An inhibitory presynaptic neuron inhibiting the membrane (slowing cell activity) 4) Going further from threshold (slowing cell activity)
  24. Describe (using Nernst) 4 ways a resting membrane can be hypopolarized.
    1) Increase the flow of Na+ (making it closer to 60mv, thus less negative) 2) Reduce the flow of K+ (making it further from -90mv, thus less negative) 3) An excitatory presynaptic neuron stimulating the membrane (stimulating cell activity) 4) Going towards threshold (stimulating cell activity)
  25. The degree of change in the resting potential is directly proportional to the intensity of stimulation; this grading of local potential changes is known as what?
    Graded Potential
  26. When threshold is reached, and sodium gates open.
    Action Potential
  27. The first part or initial segment of an axon containing many Na+ gates where a nerve impulse initially begins.
    Trigger Zone
  28. The propagation of action potentials along an axon.
    Nerve Impulse
  29. What is a nerve impulse triggered by?
    A Na+ gate being opened at -55 mv at the trigger zone
  30. Where stimuli gather before entering the postsynaptic neuron.
    Axon Hillock
  31. Initial negatively-charged state when Na+ is out and K+ is in.
    Polarization
  32. When Na+ is going in, the inside is positively charged.
    Depolarization
  33. When K+ is going out, the inside is negatively charged.
    Repolarization
  34. When Na+ is going out and K+ is going in; a threshold stimulus will not trigger another action potential.
    Refactory
  35. The period when an axon's membrane cannot be stimulated; the first part of the refractory period.
    Absolute Refactory
  36. The period in which a stronger stimulus can trigger an impulse.
    Relative Refactory
  37. A nerve impulse follows the _____, meaning the response is full-speed, full strength every time, or it doesn't respond at all.
    All-or-None Law

What would you like to do?

Home > Flashcards > Print Preview