Ch. 3

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Ch. 3
2011-09-18 17:19:45

ch. 3 vocab
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  1. action potential
    brief fluctuation in membrane pontential caused by the rapid opening and closing of voltage-gated ion channels; also known as spike, nerve impulse, or discharge. travel along axons to transfer info. from one place to another in the nervous system
  2. excitable membrane
    any membrane capable of of generating action potentials.
  3. resting membrane potential
    the membrane potential, or membrane voltage, maintained by the cell when it's not generating action potentials; aka resting potential (-65 mV)
  4. ion selectivity
    a property of ion channels that are selectivley permeable to some ions and not to others
  5. gating
    a property of many ion channels, making them open or close in response to specific signals, such as membrane voltage or the presence of neurotransmitters
  6. ion pump
    a protein that transports ions across a membrane at the expense of metabolic energy
  7. ion
    an atom or molecule that has a net electrical charge bc of a difference in the number of electrons and protons
  8. cation
    a positively charged ion
  9. anion
    a negatively charged ion
  10. phospholipid bilayer
    the arranagement of phospholipid molecules that forms the basic structure of the cell membrane. the core of the bilayer is lipid, creating a barrier to water and to water-soluble ions and molecules
  11. peptide bond
    the covalent bond between the amino group of one amino acid and the carboxly group of another
  12. polypeptide
    a string of amino acids held together by peptide bonds
  13. ion channel
    a membrane-spanning protein that forms a pore that allows the passage of ions from one side of the membrae to the other
  14. diffusion
    the temperatuare -dependent movement of molecules from regions of high concentration to low concentration resulting in more even distribution
  15. concentration gradient
    a difference in concentration from one region to another. ionic concentration gradients across the neuronal membrane help determine the membrane potential
  16. electric current
    the rate of movement of electrical charge, symbol (I) measure in amperes; the movement of electrical charge
  17. electrical potential
    the force exerted on an electrically charged particle, represented by the symbol V and measured in volts
  18. voltage
    the force exerted on an electrically charged particle; (v) measure in volts

    aka electrical potential or potential difference
  19. electrical conductance
    the relative ability of an electrical charge to migrate from one point to another; (g) measured in siemens (s). conductance is the inverse of resistance.
  20. electrical resistance
    the relative inability of an electrical charge to migrate from one point to another; (R) measured in ohms (W)
  21. Ohm's law
    the relationship between electrical current (I), voltage (V), and conductance (g)

  22. membrane potential
    the voltage across a cell membrane (Vm)
  23. microelectrode
    a probe used to measure the electrical activity of cells.
  24. ionic equilibrium potential or equilibrium potential
    the electrical potential difference that exactly balances an ionic concentration gradient, (Eion)
  25. ionic driving force
    the differenc between the real membrane potential, Vm, and the ionic equilibrium potential, Eion.
  26. nernst equation
    a mathematical relationship used to calculate an ionic equilibrium potential
  27. sodium-potassium pump
    an ion pump that removes intracellular Na+ and concentrates intracellular K+, using ATP as its energy source
  28. calcium pump
    an ion pump that removes cytosolic Ca2+
  29. goldman equation
    a mathematical relationship used to predict membrane potential from the concentrations and membrane permeabilities of ions
  30. depolarization
    a change in membrane potential, taking it from the value at rest to a less negative value
  31. blood brain barrier
    a specialization of the walls of brain capillaries that limits the movement of blood borne substances into the extracellular fluid of the brain