Muscle Contraction Physiology Important Job Related MCQs

1 - Actin has a strong affinity to myosin and readily combines with it to form actomyosin but this is inhibited by:





Troponin through its Tpc subunit

2 - After death rigor mortis occurs in the muscles because:





Actomyosin ADP complex is not broken dur to lack of supply of ATP as oxygen and other substrates for its synthesis are not present

3 - Besides ATP the other sources of providing energy for muscular contraction are:





Both (a) & (b)

4 - Chief source of energy for muscle contraction is:





Glycogen

5 - Contraction and relaxation phase of a muscle is called:





Twitch

6 - Cross bridges are found on:





Myosin

7 - Dragging of actin filaments towards 'M' line is termed as:





Power stroke

8 - During biochemical events or muscle contraction which of these processes occur:





All of these processes

9 - During first stage of breakdown of glycogen which of these occur:





Glycogen ? formation of glucose-6-phosphate

10 - During muscle contraction:





Actomyosin contracts so that cross bridges tilt dragging filaments of actin towards 'M' line

11 - During recovery phase of muscle contraction the processes occurring are:





All of these

12 - During relaxation the calcium ions are:





Forced back from sarcoplasm to sarcoplasmic reticulum

13 - Flexing or bending of our arm is done by:





Biceps

14 - Formation of lactic acid from pyruvic acid during muscle contraacton is catelyzed by which of these enzymes:





Lactic dehydrogenase

15 - Function of boosters in the contraction of cardiac muscles is performed by:





Intercalary discs

16 - Functional unit of contractile system in a striped muscle is:





Sarcomere

17 - How much lactic acid formed is broken by oxidation to form CO2 and water:





1/5 part

18 - How much lactic acid formed is resynthesized into glycogen:





4/5 part

19 - If a contracting muscle is given a second stimulus during its contraction phase then it is seen to produce 'M' curve on kymogram. This phenomenon is termed:





Summation

20 - In which of these conditions the muscle offers no contraction:





Fatigue

21 - In which of these phenomenon we get few initial sequentially increasing curves on kymogram if we stimulate a muscle periodically while permitting its normal relaxation:





Treppe

22 - M' curves on kymogram are seen during:





Summation

23 - Muscles are fatigued by accumulation of:





Lactic acid

24 - Muscular contraction involves which of these events:





Both (a) & (b)

25 - Paralysis occurs in the muscles by:





Cut off in its motor nerve supply

26 - Refractory period in frog's muscles is about:





None of these

27 - Refractory period in muscles of man is:





None of these

28 - Shivering of body and clattering of teeth in cold is a method for:





Production of heat by muscular contraction

29 - Shivering of body and clattering of teeth in winters is associated with:





Thermoregulation

30 - Sliding filament theory was proposed by:





H.E. Husley

31 - Spur-like structures are found in the molecule of:





Myosin

32 - Straightening of our flexed arm is done by:





Biceps which extends from shoulders to radius

33 - The 'A' band in myofibril occupies:





2/3rd of length of sarcomere so that muscle shortens by 1/3rd of its length during contraction

34 - The cause of muscular tentany is:





Deficiency of parathyroid hormone

35 - The contraction of of a muscle is caused by:





Actomyosin

36 - The decomposition of lactic acid is done by:





Both of these processes

37 - The energy required for muscular contraction is derived from:





ATP

38 - Troponin subunit Tpc inhibits actomyosin formation by:





Binding with Ca++ ions

39 - Under which of these disorders the muscle remains atrophied for a long time:





Paralysis

40 - Upwards and downwards rotation of body parts is done by:





Pronators and suppinators

41 - When a muscle is repeatedly stimulated during its contraction period without permitting relaxation for a very long time it does not relax. This stage is called:





Tetany

42 - Which of these are examples of antgonistic muscles in our body:





All of these

43 - Which of these are released before muscle contraction from sarcoplasmic reticulum:





Calcium ions

44 - Which of these muscle respectively flex and straighten our arm:





Biceps and triceps

45 - Which of these processes mark the beginning of muscular contraction:





Release of calcium ions from sarcoplasmic reticulum

46 - Which of these proteins are attached with actin of myofibril:





Both (a) & (b)

47 - Which of these reactions are correct:





Creatine phosphate ? Creatine + H3PO4 ADP + H3PO4 ? ATP

48 - Which of these structures over myosin help in contraction of the muscle fibre:





Cross bridges over spur

49 - Which of these substances on accumulation causes muscular fatigue:





Lactic acid

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