Final answer:
At the synapse, the action potential triggers the release of neurotransmitters from the presynaptic neuron into the synaptic cleft. These neurotransmitters then bind to receptors on the postsynaptic neuron, affecting its electrical state and the subsequent transmission of the impulse.
Step-by-step explanation:
During neuronal communication, an electrical signal known as an action potential travels down the axon of the presynaptic neuron. When it reaches the axon terminal, it triggers the opening of voltage-gated Ca2+ channels. Ca2+ ions enter the cell, which causes synaptic vesicles to merge with the presynaptic membrane and release neurotransmitters into the synaptic cleft.
Once in the synaptic cleft, neurotransmitters diffuse across this small gap and bind to receptor sites on the postsynaptic neuron. This binding opens ion channels, which can cause a depolarization or hyperpolarization in the postsynaptic neuron, and can either promote or inhibit the generation of a new action potential. This process allows neurons to transmit information to one another and is essential for all neural functions, including thought, sensation, and movement.
While chemical synapses are most common and involve neurotransmitters, some synapses are electrical, where cells connect directly via gap junctions, allowing an electric current to pass between neurons. These electrical synapses are much faster but less common than chemical ones.