MICROANATOMY

Detailed explanation-1: -Embedded in the sarcolemma (= fiber membrane) at the neuromuscular junction are (nicotinic) receptors for acetylcholine (ACh). This is the neurotransmitter that is released by the terminal branches of a motor neuron. An enlargement of an ACh receptor reveals that it is composed of five (5) polypeptide subunits.

Detailed explanation-2: -The area of synaptic contact between motor neurons and their target muscle fibers is the neuromuscular junction (NMJ). This synapse occurs at a specialized area of the sarcolemma called the endplate (Figure 1).

Detailed explanation-3: -EXPLANATION: The junction between a motor neuron and the sarcolemma of the muscle fibre is called the motor end plate. It is formed at the sites, where the terminal branches of the axon of a motor neuron contact with a muscle cell.

Detailed explanation-4: -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.