Synapses can be broadly classified into two types: chemical synapses and electrical synapses. Chemical synapses are more common and involve the release of neurotransmitters from the presynaptic neuron into the synaptic cleft, which then bind to receptors on the postsynaptic neuron. Electrical synapses, on the other hand, involve direct cytoplasmic connections between neurons through gap junctions, allowing for the direct flow of ions.