Final answer:
Neurotransmitters are released by neurons into the synaptic cleft and bind to receptors on an adjacent neuron, initiating an electrochemical response. Excess neurotransmitters are cleared by degradation or reuptake. Besides chemical synapses, there are faster but less common electrical synapses that communicate via gap junctions.
Step-by-step explanation:
Neurotransmitter Movement Across Synapses
During neuronal communication, an action potential travels down a neuron's axon to reach terminal buttons, triggering the release of neurotransmitters into the synaptic cleft. These neurotransmitters diffuse across the synapse and bind to specific receptors on the postsynaptic cell's dendrites. The match between neurotransmitters and receptors works like a lock and key due to their complementary shapes. Once the neurotransmitters bind to the receptors, they elicit an electrochemical response in the postsynaptic neuron, which may trigger another action potential, propagating the signal onward. Excess neurotransmitters are then cleared from the synaptic cleft either by degradation or reuptake, a process where they are absorbed back into the presynaptic neuron. This quick clearance allows for subsequent signals to be transmitted without interference.
While this chemical synaptic transmission is the most common, there are also electrical synapses where two neurons are connected via gap junctions, allowing the electrical charge to pass directly between cells. Electrical synapses are less common but allow for faster communication compared to chemical synapses.