Q. Statements about the mechanism of muscle contraction are given below. I. Acetylcholine is released when the neural signal reaches the motor end plate. II. Muscle contraction is initiated by a signal sent by CNS $via$ a sensory neuron. III. During muscle contraction isotropic band gets elongated. IV. Repeated activation of the muscles can lead to lactic acid accumulation. Identify the correct statement.
A) I and IV are correct
B) I and III are correct
C) II and III are correct
D) I, II, and III are correct
Explanation
The junction between a motor neuron and the sarcolemma of the muscle fiber is called the neuromuscular junction or motor-end plate. A neural signal reaching this junction (motor-end plate) releases a neurotransmitter (acetylcholine) which generates an action potential in the sarcolemma.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.