When neurotransmitters are being released by a presynaptic neuron into the synapse,it is because ____.

Question

Quizplus · Accepted Answer

Neurotransmitters are released by the presynaptic neuron in response to action potentials that occur in the presynaptic neuron. The action potentials cause depolarization of the presynaptic membrane, which triggers the release of neurotransmitters into the synapse. Option A is incorrect because the refractory period occurs after an action potential has occurred, not before. Option B is incorrect because a large concentration of Na+ ions outside the presynaptic axon would not by itself cause neurotransmitters to be released. Option C is incorrect because neurotransmitter release occurs in the presynaptic neuron, not the postsynaptic neuron.

When Neurotransmitters Are Being Released by a Presynaptic Neuron into the Synapse,it