Final answer:
The electrical signal in a neuron becomes a chemical signal upon reaching the synaptic terminal, through neurotransmitter release. These neurotransmitters bind to receptors on the postsynaptic cell, can alter its potential, and trigger a new electrical impulse. Neurotransmitters are then quickly degraded or reabsorbed.
Step-by-step explanation:
When the electrical signal in a neuron reaches the synaptic terminal, it is converted into a chemical signal through the release of neurotransmitters into the synaptic cleft. These neurotransmitters then bind to receptors on the postsynaptic cell, changing its electrochemical potential and potentially triggering another electrical signal.
The sequence is initiated by the arrival of an action potential at the axon terminal, triggering the opening of voltage-gated Ca2+ channels. Calcium ions flood into the cell, prompting synaptic vesicles to fuse with the pre-synaptic membrane and release neurotransmitters.
After their function has been served, neurotransmitters are rapidly broken down or reabsorbed by the presynaptic neuron, readying the synapse for subsequent neurotransmissions. This is crucial to ensure that the postsynaptic neuron can quickly recover and respond to new incoming signals without the interference from previous ones.