1. The nerve impulse travels along the axon of the pre-synaptic neuron to the axon terminal.
2. Pre-synaptic neurons or axons have several synaptic knobs at their ends or terminals.
3. These knobs have membranous sacs, called synaptic vesicles having neurotransmitter molecules.
4. When an impulse reaches a synaptic knob, voltage sensitive Ca channels open and calcium ions (Ca ) diffuse inward from the extracellular fluid.
5. The increased calcium concentration inside the cells, initiates a series of events that help to fuse the synaptic vesicles with the cell membrane of pre-synaptic neuron, where they release their neurotransmitters by exocytosis.
6. The neurotransmitters bind to the receptors of the post-synaptic cell,
7. This action is either excitatory (stimulating) or inhibitory (slowing down/stopping).
8. Once the impulse has been transferred across the synapse, the enzyme like acetyl cholinesterase destroys the
9. neurotransmitter and the synapse is ready to receive a new impulse.
