Dr Gawad Physiology Course Online Exam - Excitable – Course Lecture 6

7 Questions | By Gawadnephronnnnn | Updated: Mar 14, 2022 | Attempts: 152

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7 MCQs (Only one correct answer)Each MCQ: 1 mark, Total mark: 7 (you will your result immediately by the web)Allowed time: 10 minGood Luckdr Mohammed Abel Gawad

Questions and Answers

1.

During muscle contraction, all the following is true except:
- A.
  
  The binding sites at the actin filaments are activated by Ca.
- B.
  
  The sliding filament theory of contraction assumes that sliding of actin continues as long as Ca is attached to troponin C
- C.
  
  The detachment of myosin heads from actin needs binding of ATP.
- D.
  
  The transverse tubules (T.T.) contains Ca voltage gated channels
2.

About the of skeletal muscles, all the following is true except:
- A.
  
  Hypertrophy develops as a result of forced repeated contractions.
- B.
  
  The function of the T system is the rapid transmission of the action potential from the cell -membrane to inside the muscle fibre
- C.
  
  After the spike potential, the muscle excitability is abolished
- D.
  
  Acetylcholine released at the M.E.P. is rapidly hydrolyzed by cholinesterase.
3.

Among the steps of skeletal muscle relaxation:
- A.
  
  Inward spread of the depolarization wave along the transverse tubules.
- B.
  
  Pumping of Ca back into the sarcoplasmic reticulum.
- C.
  
  Release of Ca from the sarcoplasmic reticulum.
- D.
  
  Binding of Ca to troponin C.
4.

Concerning isometric and isotonic muscle contractions:
- A.
  
  In isometric contraction, the elastic elements are not stretched.
- B.
  
  During isometric contraction a load is moved and work is done.
- C.
  
  During isotonic contraction most of the energy transformed into heat.
- D.
  
  During isotonic contraction the muscle length is not changed.
5.

In skeletal muscles:
- A.
  
  The initiation of contraction occurs by binding of Ca to tropomyosin.
- B.
  
  The action potential follows the work done.
- C.
  
  The one way conduction at the M.E.P. is due to location of the chemical mediator (acetylcholine) in the nerve terminals.
- D.
  
  Fatigue sets in after fatigue occurs in the nerves.
6.

A series of stimuli that cause summation of contractions leads to:
- A.
  
  Rigor.
- B.
  
  Contracture.
- C.
  
  Tonus.
- D.
  
  Tetanus
- E.
  
  Spasm.
7.

Regarding reaction of degeneration, which of the following is true:
- A.
  
  There is increased muscle excitability
- B.
  
  Skeletal muscle responds to both faradic and galvanic current
- C.
  
  Skeletal muscle has longer chronaxie
- D.
  
  ACC is lower than CCC