Dr Gawad Physiology Course Online Exam - Excitable – Nerve Exam

17 Questions | By Gawadnephronnero | Updated: Mar 21, 2022 | Attempts: 654

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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