Neurones are not continuous there is a gap between neurones. The gap between axon of one neurone and the dendrites on the next neurone is called a synapse.
At an axon terminal, there are tiny vesicles filled with neurotransmitters which are chemical substances used by one neurone to signal another neurone. An example of neurotransmitter is acetylcholine.
Transmission of nerve impulses across synapse
When a nerve impulse reaches the axon terminal, vesicles containing neurotransmitters (acetylcholine) move towards presynaptic membrane. Vesicles fuse with the membrane, releasing neurotransmitters (acetylcholine) into synaptic cleft through exocytosis. Neurotransmitters (acetylcholine) diffuse across synapse and bind to the receptors at postsynaptic membrane. Some of the neurotransmitters (acetylcholine) are broken down by enzymes (acetylcholinesterase), taken up again by the axon terminal and recycled, or simply diffused away.