MCQ - Muscle physiology

Physiology of Muscle

Question Bank

  

1.     The dark band of a skeletal muscle are known as

a.     Isotropic or I –band

b.     Anisotropic or A-band

c.      Hansen’s or H-zone

d.     Z-line

 

2.     The light band of a skeletal muscle are known as

a.     Isotropic or I –band

b.     Anisotropic or A-band

c.      Hansen’s or H-zone

d.     Z-line

 

3.     The major protein present in thick filament of skeletal muscle fibre is

a.     Actin

b.     Troponin

c.      Myosin

d.     Tropomyocin

 

4.     The major protein present in thin filament of skeletal muscle fibre is

a.     Actin

b.     Troponin

c.      Myosin

d.     Tropomyocin

 

5.     Muscles of the heart are ------

a.     Voluntary, smooth

b.     Voluntary, striated

c.      involuntary, smooth

d.     involuntary, striated

 

6.     Sarcomere is --------------

a.     basic structural and functional unit of nervous system

b.     basic structural and functional unit of kidney

c.      basic structural and functional unit of muscle

d.     basic structural and functional unit of respiratory system

 

 

7.     How many  thin filaments, surrounding every thick filament?

a.     3

b.     6

c.      8

d.     10

 

8. The ends of the actin filaments are anchored (attached) to the:

a) M-line

b) Z-line

c) Perimysium

d) Sarcoplasmic reticulum

 

9. When a muscle fibre shortens, the following also shortens:

a) Sarcomere

b) Actin filament

c) Myosin filament

d) Z-line

 

10.  The two principal contractile proteins in skeletal muscles are

a)     actin and troponin

b)    actin and tropomyosin

c)     actin and myosin

d)    myosin and tropomyosin

 

11. The trigger to initiate the contractile process in skeletal muscle is

a)     calcium binding to tropomyosin

b)    ATP binding to the myosin cross bridges

c)     calcium binding to troponin

d)     potassium binding to myosin

 

12. After calcium ions are released from the sarcoplasmic reticulum they

a)      initiate an action potential

b)     bind to actin

c)      cause sodium channels to open in the sarcolemmal membrane

d)     bind to troponin

 

13. The A-bands of skeletal muscle do not change their width during muscle contraction because

a)      the thick filaments are not involved in the sliding filament theory

b)     the A-bands are the thick filaments themselves which do not shorten

c)      the A-bands extend beyond the sarcomere

d)     the A-bands are the thin filaments themselves which do shorten

 

14. The sustained contraction by skeletal muscles in which individual twitches cannot be detected is called

a)     summation

b)    recruitment

c)     tetanus

d)    twitching

 

16. Regarding smooth muscle

a)     it has actin and myosin filaments organized into myofibrils

b)    it is multinucleated

c)     like cardiac muscle, the cells are joined together by gap junctions called intercalated discs

d)     it is capable of prolonged contraction without fatigue and with little energy consumption

 

17. The functional unit of contractile system in striated muscle is

a) myofibril

b) Cross bridges

c) Z band

d) sarcomere

 

18. Which of the following is the contractile protein of a muscle?

a) Tubulin

b) Myosin

c) Tubulin

d) all of these

 

19. The contractile protein of skeletal muscle involving ATPase activity is

a) actin

b) myosin

c) troponin

d) tropomyosin

 

20. Which of the following is a component of actin filaments of a sarcomere?

a) myosin and troponin

b) troponin and actin

c) actin and myosin

d) troponin, tropomyosin and actin

 

21. Muscle fatigue sets in due to non availability of

a) Calcium

b) ATP

c) actin binding site

d) Mg cofactor

 

22. Muscles get fatigue due to accumulation of

a) Lactic acid

b) ATP

c) Phosphate molecules

d) Carbon dioxide

 

23. Which one of the following sets of ions are necessary in the chemical events for muscle contraction?

a) Na+ and K+

b) Ca+ and Mg++ ions

c) Na+ and Ca++ ions

d) Na+ and Mg++ ions

 

24. Light band has which of the following filament protein?

a) Myosin

b) Actin

c) Myosin and actin

d) None of these

 

25. Upon stimulation of skeletal muscles calcium is immediately made available for binding to troponin from

a) blood

b) sarcoplasmic reticulum

c) lymph

d) bone

 

26. What is sarcomere?

 

a) Part between two H line

b) Part between two A line

c) Part between two Z line

d) Part between two I band

 

27. In the striated muscles, the functional unit of contractile system is

(a) Z band

(b) cross bridges

(c) sarcomere

(d) myofibril

 

 

28. In muscle contraction, this ion is essential

a) Cl

b) Ca

c) K

d) Na

 

29. Smooth muscle is not to be found in the walls of

a)     veins

b)    venules

c)     arterioles

d)    capillaries

 

30. This organelle stores calcium and releases it when the muscle needs to contract.

 a. sarcoplasmic reticulum

 b.  sarcolemma

c.  myofibril

d. sarcomere

 

31. This is the dark banded area of a skeletal muscle

. a. A band

b. M line

 c. Z disc

d. I band

 

32. This type of muscle is striated, voluntary and multinucleated.

a. cardiac

 b. smooth

c. skeletal

 

33. The muscle that is located in the walls of hollow internal organs is

1.     skeletal muscle.             

2.     smooth muscle.

3.     cardiac muscle.                       

4.     voluntary muscle.

 

34. Skeletal muscle differs from the other two types of muscle tissue in that skeletal muscle

a.     has visible striations.                                 

b.     has only one nucleus per cell.

c.      is the only muscle tissue controlled voluntarily  

d.     contains actin and myosin filaments

 

35. An entire skeletal muscle is surrounded by ___________.        

a.     tendon sheath

b.     endomysium.

c.      sarcolemma

d.     epimysium

  36. A motor neuron and all the muscle fibers it supplies is called a(n) _________    

a.     synaptic cleft

b.     motor unit

c.      neuromuscular junction

d.     axon terminal

 37. Which of the following does NOT occur during skeletal muscle contraction?

         

a.     Calcium concentration in the sarcoplasm increases.

b.     Calcium binds to myosin heads.

c.      Myosin heads bind to actin.

d.     The I bands shorten and H zones disappear.

  .38. Each skeletal muscle fiber is controlled by a neuron at a single _______

a.     neuromuscular junction

b.     synaptic knob

c.      sarcomere

d.     synaptic cleft

 

          39. In the sliding filament model of muscle contraction, the myofilaments slide over each other, resulting in the overlapping of actin and _________.  

a.     actin

b.     tropomyosin

c.      myosin

d.     thin filaments                

40. The functional unit of contraction in a skeletal muscle fiber is the _______

         

a.     sarcolemma

b.     myofilament

c.      sarcomere

d.     sarcoplasmic reticulum

41. The space between the neuron and the muscle is the ___________.

         

a.     motor unit

b.     synaptic cleft

c.      synaptic knob

d.     motor end plate

  42. Which of the following statements is INCORRECT?

         

a.     Skeletal muscle contractions help maintain body temperature.

b.     Skeletal muscles support the weight of some internal organs.

c.      The contractions of skeletal muscles pull on tendons and move elements of the skeleton.

d.     Skeletal muscles form valves regulating the passage of substances through internal openings of the digestive and urinary tracts.       

43. Which of the following substances increases in quantity during repetitive muscle contraction during oxygen deficit?

         

1.     creatine phosphate

2.     glucose

3.     adenosine triphosphate (ATP)

4.     lactic acid

44. The sequence of electrical changes that occurs along the sarcolemma when a muscle fiber is stimulated is known as the ___________.

         

a.     resting potential

b.     membrane repolarization

c.      motor end plate potential

d.     action potential

45. Which of the following muscles is voluntary?

a.     the muscle of the stomach

b.     the muscle in the wall of the urinary bladder

c.      the muscle in the wall of the heart

d.     the muscle that extends the arm at the elbow

46. Which of the following is NOT a characteristic of skeletal muscle contraction?

         

a.     It contracts rapidly.

b.     It is voluntary.

c.      It can exert tremendous power.

d.     It can contract for long periods of time without tiring.

          47. A sarcomere is part of a(n) ___________.

          myofilament

a.     myofibril

b.     perimysium

c.      endomysium

48. The refractory period in which the muscle will NOT contract if stimulated occurs during __________ of the muscle cell.

         

a.     depolarization

b.     polarization

c.      hyperpolarization

d.     repolarization

49. Where does 95% of the energy needed for contraction come from during moderate exercise?    

a.     creatine phosphate

b.     aerobic respiration

c.      anaerobic glycolysis

d.     lactic acid

         

50. Which of the following characteristics is unique to smooth muscle?

         

a.     the ability of ATP to energize the sliding process

b.     hyperplasia

c.      response to stretch

d.     the absence of striations

 

Sliding filament theory of muscle contraction was given by

a.     Arnon and Hill

b.     Pullaman and Huxley

c.      Huxley and Huxley

d.     Pullaman and Arnon