What happens at a synapse during neurotransmission?

At a synapse during neurotransmission, neurotransmitters are released from the presynaptic neuron to the postsynaptic neuron.

Neurotransmission is a fundamental process in the nervous system that allows for the transmission of signals from one neuron to another across synapses. Synapses are the tiny gaps between neurons where communication occurs. The process begins in the presynaptic neuron, the neuron that sends the signal. When an electrical signal, known as an action potential, reaches the end of the neuron, it triggers the release of neurotransmitters.

These neurotransmitters are stored in small sacs called vesicles. When the action potential reaches the synapse, it causes these vesicles to fuse with the membrane of the neuron and release their neurotransmitters into the synaptic cleft, the tiny gap between the two neurons. This process is known as exocytosis.

Once in the synaptic cleft, the neurotransmitters diffuse across the gap and bind to specific receptors on the postsynaptic neuron, the neuron receiving the signal. This binding can either excite or inhibit the postsynaptic neuron, depending on the type of neurotransmitter and receptor involved. Excitatory neurotransmitters cause the postsynaptic neuron to fire an action potential, while inhibitory neurotransmitters prevent it from doing so.

After the neurotransmitters have done their job, they are either broken down by enzymes, taken back up into the presynaptic neuron for reuse, or simply diffuse away. This process ensures that the signal is not continuously transmitted, allowing the synapse to be ready for the next signal.

In summary, neurotransmission at a synapse involves the release of neurotransmitters from the presynaptic neuron, their diffusion across the synaptic cleft, and their binding to receptors on the postsynaptic neuron. This complex process allows for the rapid and precise transmission of signals throughout the nervous system.