Chemical conduction takes place between the two neurons i.e. between Axon terminal of one neuron and dendrite or cyton of other neuron. This takes place through formation of cleft i.e. space between the two structures as neurotransmitters are released in that space. The figure is about a chemical synapse. Thus $\mathrm{‘}\mathrm{A}\mathrm{’}$ represents axon terminal. This forms the presynaptic membrane. This contains vesicles that are filled with neurotransmitters. Thus $\mathrm{‘}\mathrm{B}\mathrm{’}$ represents the vesicles. $\mathrm{‘}\mathrm{C}\mathrm{’}$ is the space and thus it is the cleft where release of neurotransmitters will take place when impulse has reached. $\mathrm{‘}\mathrm{D}\mathrm{’}$ is the part present after the synapse i.e. it is the post synaptic membrane which contains receptors. $\mathrm{‘}\mathrm{E}\mathrm{’}$ are released in the cleft and thus these are the neurotransmitters.