Final answer:
The terms neuromodulator and neurotransmitter are not the same; the former modulates neural activity, while the latter transmits signals across synapses. In the context of the neuromuscular junction, acetylcholine is the released neurotransmitter.
Step-by-step explanation:
The terms neuromodulator and neurotransmitter are not interchangeable, so the statement is false. A neurotransmitter is a type of chemical messenger that transmits signals across a chemical synapse, from one neuron to another neuron, muscle cell, or gland cell. By contrast, a neuromodulator can modulate neuronal circuit activities, often by affecting the strength or duration of neurotransmitter effects rather than initiating a signal on its own.
At the neuromuscular junction, the neurotransmitter that is released is acetylcholine, not norepinephrine or serotonin. This neurotransmitter is crucial for muscle contraction. When neurotransmitters like acetylcholine bind to ligand-gated ion channels at the postsynaptic membrane, they cause these channels to open, which can then lead to a response in the target neuron or muscle cell. This may involve depolarization if the channels are permeable to ions that lead to excitatory postsynaptic potentials, or hyperpolarization if the channels are permeable to ions that lead to inhibitory postsynaptic potentials.