What Happens When an Action Potential Arrives at an Axon

Question

What happens when an action potential arrives at an axon terminal?  
A) Membrane voltages stimulate the axon.
B) Sodium ions are pumped out of the cell.
C) A neurotransmitter builds up so it can be used again.
D) The action potential causes an influx of phosphorous ions.
E) Chemicals relay the message at a synapse.

Accepted Answer

When an action potential arrives at an axon terminal, chemicals called neurotransmitters are released into the synapse or the small gap between the axon terminal and the next neuron or effector cell. These neurotransmitters then bind to specific receptors on the next cell, transmitting the signal onwards.