axon terminal

An axon terminal is the very tip of a neuron's long sending fiber — the little swollen ending where the cell finally hands its message to whatever comes next. A neuron is a nerve cell, and its axon is the thin cable that carries the cell's electrical signal away from the main body. At the far end, that cable doesn't just stop bluntly; it usually splits into many fine branches, and each branch ends in a tiny bulb. Those bulbs are the axon terminals, and they are the business end of the neuron, the spot built specifically for talking to another cell.

The terminal sits right up against its target — another neuron, a muscle fiber, or a gland cell — separated only by a microscopic gap. This whole junction, terminal plus gap plus the receiving surface, is called a synapse, and because the axon terminal is on the sending side, it is described as presynaptic (meaning before the synapse). When the neuron's electrical signal races down the axon and arrives at the terminal, it triggers the bulb to release tiny packets of chemicals called neurotransmitters. These drift across the gap and land on the next cell, passing the message along. So the axon terminal is best pictured as a loading dock at the end of a delivery road: the signal arrives, gets converted into a chemical parcel, and is shipped across the gap to the cell waiting on the other side.