Bio 580 exam 1

  1. Things to know about plasma membranes.
    Barrier made of lipids (hydrophobic and hydrophilic regions). Fluidic. Selective in letting things through. Lipids and proteins. Ion gradient maintained across membrane na+/k+. Myelin acts as an insulator. Phospholipids are amphilic.
  2. Neurons communicate using electricity carried by?
    Ions moving across plasma membranes
  3. Salts dissociate into ions in water which is essential for?
    Electrophysiology
  4. This acts as a barrier to ions.
    Lipid bilayer
  5. Are transmembrane proteins that selectively allow ions to diffuse across membranes.
    Ion channels
  6. Ionic flows is the same as?
    Electrical current
  7. Current depends on ionic flow, which depends on
    Conductance
  8. The relationship between ion flow (current an conductance is described by Ohm?s law
    I=g.V
  9. I=
    Current amps
  10. G=
    Conductance Siemens or mho
  11. V=
    Voltage electrophysiology driving force
  12. R=
    1/g resistance ohm
  13. V=IR
    The more physics version of Ohms law
  14. Electrical signals in biological systems use ions instead of electrons to?
    Carry current
  15. Ions can pass across membranes only through specialized?
    Transmembrane proteins
  16. Electrical signals in biological systems still follow ohms law-conductance is equivilant to the amount of open?
    Ion channels present
  17. The na/k ATPase uses the energy of ATP hydrolysis to?
    Set up NA and K gradients across the membrane.
  18. All cells have a membrane potential of?
    -65mV
  19. This allows theK+ to equilibrate across the plasma membrane in all cells
    K+ leak channel
  20. This equation calculates the equilibrium potential for a single ion species.
    The Nernst equation
  21. What is the Nernst equation?
    Ex = RT/zF ln (X)out / (X)in
  22. In gK = 0 and gCl = 0, what are the equilibrium potentials EK and ECl?
    Use the Nernst equation to find. -80 and 80
  23. If gK =0 and gCl =0, what is the membrane potential for the cell?
    0 No conductance = No movement
  24. If gK > 0 and gCl = 0 , what is the membrane potential for the cell?
    -80mV
  25. If gK > 0 and gCl >0, what is the membrane potential for the cell?
    0
  26. Equilibrium potential =
    Membrane potential
  27. Increasing extra cellular K+ but not Na+ can ________ the membrane potential.
    Depolarize
  28. These cells carry out spatial buffering of K+
    Glial Cells called astrocytes
  29. The occurs when thee is conductance for one ion but not its counter-ion.
    Nernst equilibrium
  30. A tiny amount of ionic movement is sufficient to establish a
    Nernst equilibrium
  31. A typical resting potential is mostly established by K+ leak channel conductance, but some _____ conductance also contribute.
    Na+
  32. Which Ion has the most important role in deciding the resting potential of a neuron?
    K+
  33. Action [potentials occur only on?
    Axons
  34. Specialized extensions of neurons. (Stick out)
    Neuritis
  35. Receive information from other neurons. Contains only some organelles(mitochondria, cytoskeleton)
    Dendrites
  36. Sends information to the other neurons.
    Axons
  37. The cell body of a neuron
    Some
  38. This is where the axon joins soma
    Axon Hillock
  39. Injecting current into the cell needs to be greater than what in order to stimulate a action potential?
    -40mV
  40. Action potentials are
    All-or-none
  41. Describes the potential for and direction of ionic movement
  42. If Vx is + then?
    Movement is out
  43. If Vx is ? then?
    Movement is inward
  44. Inward Na+ current during the rising phase of an action potential is carried by?
    Voltage-gated Na+ channels
  45. Voltage-gated channels are only express on?
    Axon membranes
  46. Ion channels activity can be monitored using?
    Single channel patch clamp recording
  47. Membrane repolarization during the falling phase of an action potential uses?
    Delayed-rectifying K+ channels
  48. Action potentials are propagating wave of membrane depolarization from the soma t the?
    Axon terminal
  49. Is a measure that allows one to tell weather an ion will move at any given time, and in which direction
    Driving force
  50. Most properties of the action potential can be explained by
    Voltage-gated Na+channels and delayed rectifying K+ channels
  51. Channel properties can be measured using
    • Single channel patch clamp recordings
    • Which ion is more important for membrane depolarization during action potential?
    • Na+
  52. Which ion is more important for membrane repolarization during action potential
    K+
  53. A smaller T will
    Increase membrane potential and will depolarize faster
  54. A larger lambda will?
    Give you a longer decay
  55. If the goal was to have membranes tat could passively depolarize faster and father how would you change the parametersT and Lambda?
    Make T smaller and Lambda larger
  56. Resistance is inversely proportional to?
    Area
  57. Capacitance is proportional to?
    Area
  58. Capacitance in inversely proportional to?
    Thickness
  59. Oligodendrocytes and other glial cells form _______ that insulate axons
    Myelin Sheathes
  60. Facilitate salutary conductance
    Slatatory jumping
  61. Membranes have passive electrical behaviors called
    Cable properties
  62. The time constant t=RmxCm. T doesn?t not change significantly with
    Axon size
  63. The length constant l =(Rm/Ri)1/2. I increases with
    Axon diameter
  64. Myelinating increases I without substantially changing
    t.
Author
MagusB
ID
348856
Card Set
Bio 580 exam 1
Description
Bio 580 exam 1
Updated