physiology

During synaptic communication, an action potential arrives at at an axon terminal causing depolarization. This depolarization leads to opening of the voltage gated Ca2+ channels which allows Ca2+ to enter the cell. The introduction of this calcium triggers exocytosis of synaptic vesicle contents,  so the neurontransmitters are released and they diffuse across the synaptic cleft. They bind with the receptoors on the post synaptic cleft, this binding initiates a response in the post synaptic cell. Communication begins with an action potential and this potetential creates a chain reaction that ultimately leads to a response in the post synaptic cell. This signal can also be stopped in a couple different ways. Neurontransmitters can diffuse out of the synaptic cleft, others are degraded by enzymes, and some are taken out of the synaptic cleft by reuptake channels.