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Multiple Choice
Which event triggers the creation of an action potential in a neuron?
A
The release of neurotransmitters into the synaptic cleft
B
The active transport of K$^+$ ions into the neuron
C
A rapid influx of Na$^+$ ions through voltage-gated sodium channels
D
The closing of all ion channels in the neuron's membrane
Verified step by step guidance
1
Step 1: Understand the concept of an action potential. An action potential is a rapid electrical signal that travels along the membrane of a neuron. It is initiated by changes in ion concentrations across the neuron's membrane.
Step 2: Recognize the role of voltage-gated sodium (Na$^+$) channels. These channels open in response to a change in membrane potential, allowing Na$^+$ ions to flow into the neuron.
Step 3: Identify the triggering event. The rapid influx of Na$^+$ ions through these voltage-gated sodium channels causes the membrane potential to become more positive, initiating the action potential.
Step 4: Compare the options provided. The release of neurotransmitters into the synaptic cleft and the active transport of K$^+$ ions are important processes in neural communication but do not directly trigger an action potential. Similarly, the closing of all ion channels would prevent ion movement and halt the action potential.
Step 5: Conclude that the correct event triggering the action potential is the rapid influx of Na$^+$ ions through voltage-gated sodium channels, as this depolarizes the membrane and initiates the electrical signal.