MUSCLE PHYSIOLOGY

Detailed explanation-1: -Answer and Explanation: The gap between the axon terminal of a motor neuron and the sarcolemma of a skeletal muscle cell is known as the neuromuscular junction. Therefore, the correct answer is (d).

Detailed explanation-2: -Cell membranes of motor nerve terminals and muscle fibers are separated by a space called the synaptic cleft, which is approximately 30 – 50 nm. In the synaptic cleft, acetylcholinesterase is concentrated to hydrolyze the neurotransmitter acetylcholine to terminate each synaptic transmission.

Detailed explanation-3: -Between the synaptic end bulbs of the neuron and the cell membrane of the muscle fiber (the sarcolemma) lies a space known as the synaptic cleft, which is the final component of the neuromuscular junction.

Detailed explanation-4: -The space within the primary and secondary clefts, located between the axon terminal and the postsynaptic sarcolemma, comprises the synaptic cleft. This space is filled with basal lamina containing acetylcholinesterase (AChE).