Explain why post-synaptic potentials dissipat, but action potentials dont

Expert Solution

Answer.

Postsynaptic potentials are changes in the membrane potential of the postsynaptic terminal of a neural synapse. Postsynaptic potentials are graded potentials, which means that they are caused by the presynaptic neuron releasing neurotransmitters from the terminal bouton at the end of an axon into the synaptic cleft. The neurotransmitters bind to receptors on the postsynaptic terminal, such that different receptors for the same neurotransmitter may open different types of ion channels. Postsynaptic potentials begin to be terminated when the neurotransmitter detaches from its receptor. Ion channels that had been opened by the receptor now get close. Once the channels are closed, ions return to their equilibrium states and thus gradually leads to the graded termination of the postsynaptic potential. However, an action potential is generated only when the postsynaptic neurons is depolarised- the charge inside the cell is -55 mV. Thus, Action potentials do not dissipate ; they are all-or-none responses.

Hayet Jeridi answered 6 months ago

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