Nerve Muscle (Physiology practice multiple choice questions for FCPS, MRCP, USMLE, and PLAB)

Nerve Muscle MCQs:

1) Which of the following has slowest conduction

a. A alpha           

b. A gamma

c. B fibres           

d. C fibres

Ans. d

2) A man falls into deep sleep with one arm under his head. After awakening the arm is paralyzed but tingling sensation and pain sensation persists. This loss of motor function without the loss of sensory function is due to

a. A fibres are more susceptible to hypoxia that B            

b. A fibres are more sensitive to pressure than C

c. C fibres are more sensitive to pressure than A              

d. Sensory nerves are nearer bone and hence affected by pressure

Ans. b

3) Saltatory conduction

a. is seen only in myelinated nerve fibres            

b. is slower that non saltatory conduction

c. is not affected if a local anesthetic is applied to the node of Ranvier   

d. none of the above

Ans. a

4) Myelin sheath is produced by

a. axoplasm       

b. mitochondria

c. scawann cell

d.   muscle cell

Ans. c

5) The action potential of skeletal muscle

a. has a prolonged plateau phase            

b. spreads inwards to all parts of the muscle via T tubules

c. is longer than the action potential of cardiac muscle   

d. is not essential for muscle conduction

Ans. b

6) Smooth muscle need help of

a. calmodulin for contraction     

b. acetyl choline for contraction

c.K+ for contraction       

d. monoamine oxidase for contraction

Ans. a

7) The cross bridges of the sarcomere in skeletal muscle are components of

a. actin

b. myosin

c. troponin         

d. tropomyosin

Ans. b

8) The likely mechanism through which neostigmine acts in improving muscular weakness is

a. It blocks action of acetylcholine           

b. it interferes with action of mono-amine oxidase

c. it enhances the action of catecholamines        

d. it blocks the action of acetyl choline esterase

Ans. d

9) A skeletal muscle

a. obeys all or none phenomenon           

b. becomes less excitable when its membrane becomes hyperpolarized

c. has a resting membrane potential positive inside        

d. contains excessive Na+ in intracellular compartment

Ans. a

10) The function of tropomyosin in skeletal muscle is-

a. sliding on actin to produce shortening              

b. Releasing Ca++ after initiation of contraction

c. binding to myosin during contraction

d. covering up the actin binding sites of myosin at rest

Ans. d