Dr Gawad Physiology Course Online Exam - Excitable – Nerve Exam

17 Questions | Total Attempts: 618

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17 MCQs (Only one correct answer)Each MCQ: 1 mark, Total mark: 17 (you will get the results immediately with correction by the web)Allowed time: 20 minGood Luckdr Mohammed Abel Gawad


Questions and Answers
  • 1. 
    Action of potential of the nerve is:
    • A. 

      Local unpropagated

    • B. 

      propagated

    • C. 

      Occurs in one direction

    • D. 

      None of the above

  • 2. 
    The first point of repolarization is:
    • A. 

      The last point depolarized

    • B. 

      The first point stimulated (depolarized)

    • C. 

      The myleinated area

    • D. 

      None of the above

  • 3. 
    Stimulation with a threshold stimulus leads to:
    • A. 

      Local unpropagated impulse

    • B. 

      Temporal summation

    • C. 

      Propagated action potential

    • D. 

      None of the above

  • 4. 
    Chemical & metabolic changes (ATP break down) occurs in nerve during:
    • A. 

      RMP

    • B. 

      Depolarization

    • C. 

      1 & 2

    • D. 

      None of the above

  • 5. 
    Which of the following is false regarding local response (local excitatory state)
    • A. 

      There is decrease in RMP

    • B. 

      There is increase in excitability

    • C. 

      It is propagated potential

    • D. 

      Caused by subthreshold stimuli

    • E. 

      Can be summated

  • 6. 
    Which of the following is true regarding strength-duration curve:
    • A. 

      Utilization time is the fastest response by the strongest strength.

    • B. 

      Rheobase strength leads to local excitatory state

    • C. 

      The longer the chronaxie the higher the excitability

    • D. 

      Minimal time is the fastest response, whatever the strength of the stimulus

  • 7. 
    Which of the following is not a membrane stabilizer:
    • A. 

      Procaine

    • B. 

      Hypoxia

    • C. 

      Hypocalcemia

    • D. 

      Hypokalemia

  • 8. 
    Which of the following is true regarding conduction in unmyelinated nerve fibers:
    • A. 

      1. It is in the form of saltatory conduction

    • B. 

      2. It saves energy

    • C. 

      3. It is local unpropagated

    • D. 

      4. It is in the form of continuous conduction

  • 9. 
    Which of the following is the most excitable area of a myelinated nerve fiber:
    • A. 

      The terminal axon

    • B. 

      Cell body

    • C. 

      Nodes of ranvier

    • D. 

      The internodeal areas

  • 10. 
    According to the active (Na-K) pump, which is false:
    • A. 

      Trans membrane protein showing large number of binding sites on its exterior aspect

    • B. 

      Inner ATPase activity is concerned to produce conformational change followed by 2 K+ pumped inside

    • C. 

      Ions migrate uphill against both (concentration + electrical) gradient

    • D. 

      Binding of (Na – K) to their respective binding sites is followed by activation of the inner ATPase

  • 11. 
    The main cause of depolarization of nerve is:
    • A. 

      K outflux

    • B. 

      Na influx

    • C. 

      Cl outflux

    • D. 

      None of the above

  • 12. 
    At stage of complete depolarization of action potential of the curve:
    • A. 

      K out flux is the major change

    • B. 

      Na out flux is the major change

    • C. 

      The potential difference between outer and inner surface is Zero

    • D. 

      Na-K pump is acting with full capacity

  • 13. 
    Reversal of polarity, which is true:
    • A. 

      Outer membrane is more negative than inner membrane.

    • B. 

      Action potenial is – 50 mv

    • C. 

      Potential magnitude is + 35 mv

    • D. 

      None of the above

  • 14. 
    Which of the following is a representation of hypopolarized state:
    • A. 

      A- Stage of rapid depolarization

    • B. 

      B- After depolarization

    • C. 

      C- After hyperpolarization

    • D. 

      D- All after potential stages

  • 15. 
    Which of the following is false regarding compound action potential:
    • A. 

      The largest the diameter the fastest velocity conduction

    • B. 

      Myleinated (medullated) nerves are faster than non myleinated

    • C. 

      The larger the diameter the longer the duration of the spike

    • D. 

      The larger the diameter the bigger the magnitude of action potential

  • 16. 
    Which of the following is not applying all or none rule:
    • A. 

      Single nerve fiber

    • B. 

      Single nerve fiber of mixed nerve

    • C. 

      Whole skeletal muscle

    • D. 

      Cardiac muscle

  • 17. 
    The main cause of after hyperpolarization is:
    • A. 

      1- Delayed Na channel closure

    • B. 

      2- Massive inward movement of Cl ions

    • C. 

      3- Delayed voltage K channels closure

    • D. 

      4- Na-K pump activation

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