Select the correct statements regarding mechanism of muscle contraction. Choose the most appropriate answer from the options given below:
- B, C and E only
- C, D and E only
- A and D only
- B, D and E only
Answer
(1) B, C and E only
Solution
A. Muscle contraction is initiated by a signal sent by the CNS via a motor neuron, not a sensory neuron. Incorrect.
B. The neurotransmitter (acetylcholine) released at the neuromuscular junction generates an action potential in the sarcolemma. Correct.
C. Increased Ca++ level leads to the binding of calcium with troponin on actin filaments. Correct.
D. This removes the masking of active sites for myosin on actin (unmasking), so the statement is incorrect.
E. Utilising the energy from ATP hydrolysis, the myosin head binds to the exposed active sites on actin to form a cross bridge. Correct.
Correct statements: B, C and E.
Answer: (1)