Nerve and Muscle Important Questions for 1st Year Mbbs by Dr. Roomi

IMPORTANT QUESTIONS OF NERVE AND MUSCLE PHYSIOLOGY FOR 1ST YEAR MBBS STUDENTS BY DR. ROOMI Q.1: Define resting membrane potential. How is it generated in a skeletal muscle? 1,4 (UHS 2006, 2007). Q. 2: Draw strength duration curve. Define the units of excitability and give their clinical application? What is meant by Utilization time? (2 + 1 + 1 +1 marks) Q.3: What is Spike Potential? Why Sodium ions cannot pass through Potassium channels? Give the ionic basis of Absolute refractory period, After depolarization and After Hyperpolarization. (1 + 1 + 1 +1 +1 marks) Q. 4: Define REFRACTORY PERIOD and its types. What is its mechanism? Give the normal value of ABSOLUTE REFRACTORY PERIOD of skeletal muscle? (2+2+1 ) Q.5: what is sattatory conduction? What are its advantages? which nerve fibers have the maximum velocity of conduction? (2004 UHS). Q.6: Explain the impulse conduction along a myelinated nerve fiber. Q.7: Compare the saltatory & non-saltatory conduction of nerve impulse. (5 marks) Q.8: Mr. X fell down and injured his elbow. He consulted a surgeon who told him that the nerve near his elbow has been damaged. Later on weakness in the muscles of forearm started. Explain the changes occuring in the nerve fiber when these undergo degeneration. (2008 S UHS). Q.9: What is compound action potential? Draw and label it. (2004S UHS). Q. 10:VWhen sciatic nerve is electrically stimulated, which type of potential record is obtained? Draw & explain it. Q.11: What is Walk-along theory & sliding filament model of skeletal muscle contraction? (2.5 + 2.5 marks) Q.12: What is sarcomere? What HISTOLOGIC changes occur in it during the muscle contraction? 2,3 (2004 S UHS).

Q.13: An unidentified dead body was found in a street. The dead body was having rigidity. It was handed over to the police. After about 24 hours, rigidity of the dead body had disappeared. a. Why was the dead body having rigidity and what is that condition called? b. Why did the rigidity disappear? c. What is the forensic significance of this condition? (3+2 marks) Q.14: Two different patients present with arterial pH of 7.6 and 7.4 respectively. In which case tetany may be aggravated more easily and why? (1 + 4 marks) Q.15: A hyperventilating young girl of 20 years reports to her physician with a typical position of the hand at the wrist due to spasm of muscles. An I/V injection of a calcium salt results in remarkable improvement of the girl’s condition. a. What is the technical name given to this condition of the girl? b. Why was calcium so effective? c. What is the role of calcium in muscle contraction? (1+2+2 marks) Q.16: Draw and label a neuromuscular junction. How is end plate potential produced? What changes occur in this potential in myasthenia gravis? 2,2,1, (UHS 2005, 2007) Q.17: A 30 year old lady complained of double vision (diplopia), severe muscle weakness & fatigue. She has drooping of eyelids and an enlarged shadow of thymus on ultrasound. a. b. c. d.

What can be the possible diagnosis of this disturbed physiology? What is the physiological basis of this pathology? What positive finding do you expect in her serum examination? What medicine can alleviate the lady’s complaints?

Q.18: what is end plate potential? How is it produced? How is it affected in myasthenia gravis? (2004, 2008 UHS). 1+2+2 Q.19: What is the mechanism of action of Post-synaptic neuro-muscular transmission blockers? Classify them with examples and give their uses. (1 + 3 + 1 marks)

Q.20: Differentiate between Unitary and Multiunit smooth muscle.

(5 marks)

Q.21: What is latch phenomenon in a smooth muscle fiber? What is its importance and how is it regulated? 2,1,2 (2006 UHS).