A neuron communicates by sending an action potential down its axon and releasing neurotransmitter. Which of the following correctly describes the process of an action potential. (1) rapidly enters the cell causing a depolarization, followed by the efflux of (2), which repolarizes the cell. Once the action potential reaches the presynaptic terminal, (3) enters the cell, which causes the release of neurotransmitter?
Loading ...
Correct Answer: C. (1) Sodium (2) Potassium (3) Calcium
Neurons are at rest with a negative membrane potential relative to the outside of the cell. During an action potential, positively charged sodium ions rush into the cell making the membrane potential less negative (depolarization). Soon after, potassium (another positively charged ion) exits the cell and restores polarization. The presynaptic terminal reacts to the action potential by opening calcium channels. This calcium is required for the cellular machinery responsible for neurotransmitter release into the synapse.
Subscribe below to receive the DAT Question of the Day delivered straight to your inbox every morning.
