Problem:
Question 1: Which of the following structures is NOT a part of the muscle fiber?
A. transverse tubule
B. motor end plate
C. sarcolemma
D. synaptic knob
E. sarcoplasmic reticulum
Question 2: You briefly apply a high concentration of acetylcholine (ACh) directly to the motor end plate and observe no contraction of the fiber. Since muscular dysgenesis only affects one type of cell in the body you would suspect that the motor neurons of dysgenic mice work normally. True or False?
A. True
B. False
Question 3: Arrange the events at the neuromuscular junction in the proper sequence from first to last
1. arrival of the action potential at the synaptic knob
2. generation of action potential in sarcolemma
3. binding of ACh to ACh receptors in the motor end plate
4. release of ACh into the synaptic cleft
5. removal of ACh from the cleft by acetylcholinesterase
A. 1, 2, 3, 5, 4
B. 2, 3, 1, 4, 5
C. 1, 4, 3, 2, 5
D. 2, 5, 1, 4, 3
Quetion 4: After you apply acetylcholine to the muscle fiber you find that an action potential is generated in the sarcolemma. This result proves that certain events or conditions occur normally within the neuromuscular junction. Which event or condition is NOT PROVED by the above result?
A. ACh receptors are present in the membrane of the motor end plate
B. ACh receptors bind to ACh
C. Sodium permeability of the end plate membrane is increased
D. Acetylcholinesterase breaks down ACh
Question 5: Arrange the events of excitation contraction coupling in the proper sequence from first to last
1. cross-bridge cycling
2. action potential in the sarcolemma reaches the triads
3. release of calcium from the sarcoplasmic reticulum
4. exposure of active site on the thin filaments
5. binding of calcium to troponin
A. 2, 3, 5, 4, 1
B. 5, 3, 4, 2, 1
C. 5, 1, 3, 2, 4
D. 3, 5, 2, 4, 1
Please suggest correct answer and justify your answer.