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Multiple Choice
Which neurotransmitter is released by motor neurons at the neuromuscular junction?
A
Serotonin
B
Acetylcholine
C
GABA (gamma-aminobutyric acid)
D
Dopamine
Verified step by step guidance
1
Understand the context: The neuromuscular junction is the site where a motor neuron communicates with a muscle fiber to initiate muscle contraction. The neurotransmitter released here plays a critical role in transmitting the signal from the neuron to the muscle.
Recall the function of neurotransmitters: Neurotransmitters are chemical messengers that transmit signals across a synapse from one neuron to another cell, such as a muscle cell in this case.
Identify the neurotransmitter associated with motor neurons: Motor neurons release a specific neurotransmitter at the neuromuscular junction to stimulate muscle contraction. This neurotransmitter binds to receptors on the muscle cell membrane, leading to depolarization and subsequent muscle contraction.
Review the options provided: Serotonin, GABA (gamma-aminobutyric acid), Dopamine, and Acetylcholine. Consider the roles of each neurotransmitter. For example, serotonin is involved in mood regulation, GABA is an inhibitory neurotransmitter in the central nervous system, and dopamine is associated with reward and motor control.
Conclude that the correct neurotransmitter released by motor neurons at the neuromuscular junction is Acetylcholine, as it is specifically responsible for transmitting signals to muscle fibers to initiate contraction.