Differences between action potential and graded potential

S.N  Action potential S.N  Graded potential
1. It is the electrical potential change that occurs when impulse transmits along the membrane of the nerve or muscle cell. 1. It is the membrane potential that can vary in amplitude.
2. Related with long distance signal. 2. Related with short distance signal.
3. Occurs in two phases i.e., depolarization and repolarization. 3. Occurs in one phase either depolarization or hyperpolarization.
4. All-or-none law obeyed. 4. All-or-none law not obeyed.
5. There is no possibility of summation. 5. There is possibility of summation.
6. Refractory period is present. 6. Refractory period is not present.
7. Ligand-gated ion channels generate action potential. 7. Voltage-gated ion channels generate graded potential.
8. Chance of losing its strength during transmission. 8. No chance of losing its strength during transmission.
9. Occurrence takes in excitable membranes only of specialized cells like neuron and muscles. 9. Occurrence takes in most plasma membrane.
10. Before action potential initiates, depolarization to threshold level most occur. 10. There is no threshold level.
11. Occurs for 1-2msec. 11. Occurs for few milliseconds to seconds.
12. Ions involved are mostly Na+, Clor K+. 12. Ions involved are Na+ and K+.
13. Large amplitude of -100mV. 13. Amplitude is generally small (a few mV to tens of mV).
14. In neuron segment, occurs in axon. 14. In neuron segment, occurs in dendrites and cell body.

Graded Potentials

Image source: byuidaho

References: 

i) https://www.physiologyweb.com/lecture_notes/neuronal_action_potential/neuronal_action_potential_graded_potentials_versus_action_potentials.html#:~:text=Graded%20potentials%20are%20brought%20about,by%20membrane%20depolarization%20to%20threshold.

ii) https://pediaa.com/difference-between-graded-potential-and-action-potential/

 

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