BIO 377 CARLA #2

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Author:
tames38
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289764
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BIO 377 CARLA #2
Updated:
2014-11-20 23:03:46
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BIO 377 Exam1 CARLA
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science,medical physiology
Description:
CARLA question set #2 for BIO 377 at UMaine (Fall 2014). These questions pertain to Exam 1.
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  1. The autonomic nervous system is made up of which subsystems?



    Original question text: "Which of the following is located in the autonomic nervous system?"
    sympathetic nervous system & parasympathetic nervous system
  2. Afferent neurons transmit information from the _________ to the __________.



    Original question text: "Which of the following accurately describes afferent neurons?"
    periphery; CNS
  3. Information is transmitted from cell to cell across the chemical synapse via a(n) ________.
    neurotransmitter
  4. An action potential originates at the ______ and travels along the axon until it reaches the ______.
    axon hillock; axon terminal
  5. What type of ion channels in the membrane of neurons open or close in response to a neurotransmitter binding to its receptor?
    ligand-gated channels
  6. In neuron, where are voltage-gated calcium channels located?
    axon terminal
  7. Sensory receptors are associated with what functional class of neurons?
    afferent
  8. The myelin sheath that coats an axon acts to ______.
    reduce a membrane's ion permeability
  9. The movement of an electrical charge across a membrane describes _________.
    a current
  10. The resistance to an ion's movement across a membrane is determined by __________.
    ion channels within the membrane
  11. What is true about the Na+/Kpump?

    Hint: What does it do in regards to the resting membrane potential?



    Original question text: "Which of the following statements about the Na+/Kpump is true?"
    • The Na+/K+ pump contributes to the resting membrane potential.
    • The Na+/K+ pump is necessary for maintenance of the resting membrane potential.
  12. What is true of a neuron at rest in regards to sodium and potassium ions?

    Hint: The answers are regarding permeability, equilibrium, and electrochemical force, respectively.



    Original question text: "Which of the following statements is true when a neuron is at rest?"
    • Permeability to potassium is greater than permeability to sodium.
    • Potassium is nearer to being at equilibrium than sodium.
    • There is a stronger electrochemical force acting on sodium ions than on potassium ions.
  13. The electrochemical gradient for sodium across the membrane is such that the net flux of sodium will be ________, thereby causing the cell's membrane potential to become more _______.
    inward; positive
  14. The membrane's potential at which here is no net flux of an ion across the membrane is called that ion's ________.
    equilibrium potential
  15. As a membrane's permeability to a particular ion increases, membrane potential will move ________ that ion's _________.
    closer to; equilibrium potential
  16. The opening of an ion channel increases a cell membrane's _______, whereas _________ will decrease.
    conductance; resistance
  17. A change in a cell's membrane potential, such that it becomes more negative, is referred to as a ________.
    hyperpolarization
  18. A ________ is a subthreshold change in membrane potential within the cell body that decays as it travels away from its point of origin.
    graded potential
  19. What triggers an action potential?




    Original question text: "Which of the following does NOT produce a graded potential?"
    arrival of a suprathreshold stimulus at the axon hillock
  20. Which of the following statements is false?

    A) Graded potentials and action potentials can change the membrane potential can change the membrane potential of adjacent areas of the membrane through electronic conduction
    B) Graded potentials and action potentials are all-or-none.
    C) Graded potentials and action potentials are caused by ions moving through channels.
    D) Graded potentials do not have refractory periods, but action potentials do.
    E) Graded potentials can sum over time but action potentials cannot.
    B) Graded potentials and action potentials are all-or-none.
    (this multiple choice question has been scrambled)
  21. Describe spatial summation.

    Hint: Give a vague "example."



    Original question text: "Which of the following is an example of spatial summation?"
    Two stimuli from two sources produce graded potentials on the same neuron at the same time such that the potentials sum.
  22. What change in membrane potential is considered excitatory?



    Original question text: "Which of the following changes in membrane potential is considered excitatory?"
    depolarization
  23. If the graded potential remains above threshold once it reaches the _________, an action potential will be generated.
    axon hillock
  24. The opening of sodium channels causes a rapid _______ of sodium that ________ the neuron's membrane.
    influx; depolarizes
  25. The depolarization phase of the action potential is generated by a rapid _______.
    opening of sodium channels
  26. The repolarization phase of the action potential in a neuron is driven by the ________.
    closure of sodium channels and opening of potassium channels
  27. For the sodium channel to open and allow sodium into the cell, ________.
    the activation and inactivation gates must both be open
  28. Stimuli A and B are both suprathreshold stimuli that last for one second, but stimulus A is stronger. What is true of the action potentials they will create?



    Original question text: "Stimuli A and B are both suprathreshold stimuli that last for one second, but stimulus A is stronger. Which of the following statements is true?"
    Stimulus A will cause a higher frequency of action potentials.
  29. During which phase of an action potential are the majority of the voltage-gated sodium channels closed and incapable of opening?



    Original question text: "During which of the following states are the majority of the voltage-gated sodium channels closed and incapable of opening?
    During the absolute refractory period.
  30. The regenerative nature of a sodium channel's activation gate refers to the situation where an activation gate's opening, and the resulting depolarization, _____________.


    Hint: It stimulates ...
    stimulates the opening of another sodium channel's activation gate.
  31. The positive feedback loop that is involved in the generation of an action potential is terminated by the ________.
    closure of inactivation gates on sodium channels
  32. The all-or-none principle associated with the action potential states that _______.


    Hint: once membrane potential reaches _______, an action potential will ...
    once membrane potential reaches threshold, an action potential will be generated and that action action potential will always look the same
  33. In order for a neuron to move from the absolute to the relative refractory period, a majority of that neuron's sodium channels must have their _______.
    inactivation gates open
  34. What is true of the absolute refractory period?


    Hint: Regarding sodium & potassium



    Original question text: "Which of the following is true about the absolute refractory period?"
    • The majority of sodium inactivation gates are closed.
    • Permeability to potassium is greater than it is at rest.
  35. The relative refractory period is ________.


    Hint: due primarily to...
    due primarily to increased permeability for potassium
  36. The stimulus intensity required to initiate an action potential is ________ through the latter course of the relative refractory period.


    Hint: How does it change over time?
    progressively reduced
  37. As an action potential is propagated away from the axon hillock, propagation continues in only one direction because ________.
    the region just behind the action potential is in the absolute refractory period
  38. In myelinated nerve fibers, action potentials are produced at the ________.
    nodes of Ranvier
  39. The jumping of an action potential from node-to-node is called ________.
    saltatory conduction
  40. Which of the following axons would have the fastest conduction velocity?

    A) diameter = 5 microns, myelinated
    B) diameter = 20 microns, unmyelinated
    C) diameter = 5 microns, unmyelinated
    D) diameter = 5 microns, myelinated or unmyelinated (myelination doesn't affect conduction speed)
    E) diameter = 20 microns, myelinated
    E) diameter = 20 microns, myelinated
    (this multiple choice question has been scrambled)

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