Action potential occurs when there is a change in the electric potential and communicates with the other nerves. For the action potential to takes place there should be a short term change in the electrical potential that is created by the pressure, chemicals or by any other stimuli.
The electric potential changes from -70mV to about +30mV and is in action potential for about 1ms. Action potential starts with the graded potentials of at least 15 to 20mV. Thus before an action potential to start depolarization threshold is required.
Synapses are the points that make the neurons to communicate with each other and the transmission of information between the synapses is called the synaptic transmission that is a chemical event and is done by chemical synapse.
Events that take place during synaptic transmission are
• Nerve impulse makes the neurotransmitter to release from the presynaptic axon terminal to the synaptic cleft
• This released neurotransmitter diffuses in the cleft and binds to the postsynaptic receptor
• If sufficient neurotransmitters are bound to the postsynaptic receptor the impulse is transmitted and the neurotransmitter is collapsed by the enzymes, sent to the presynaptic receptor for further use or diffuses.