Action Potential Research Paper

Action Potential Research Paper

An action potential is the rapid depolarisation of the membrane potential to +40mV from its resting potential of –70mV. The resting potential of a neuron is the difference in electrical voltage between the inside and outside of the neuron's membrane.



An action potential is a short electrical impulse generated at the axon hillock which travels the length of an axon. Its generation happens in three distinct stages, depolarisation, repolarisation and hyperpolarisation. When the threshold of excitation is reached, depolarisation starts, the threshold is between –55mV and –65mV in most neurons. When the neuron is stimulated voltage–activated Sodium (Na+) channels open, allowing Na+ ions to rush into the neuron. This reverses the polarity in the neuron towards its peak of +40mV. At this peak Na+ channels ... Show more content on Helpwriting.net ...In this stage, there are too many K+ ions outside the axon, causing the membrane potential to be too low. The resting membrane potential is returned to –70mV after these ions diffuse.



The propagation of an action potential describes the movement of an action potential along an axon. This is done through the regeneration of the action potential at different points as Na+ ions move along the axon. The propagation of an action potential along a myelinated axon is quicker than in unmyelinated axons. This is due to Saltatory conduction; where an action potential moves from one node of Ranvier to another, along an axon. Saltatory conduction allows for faster and more efficient propagation.



Two laws govern the generation and propagation of an action potential, the All–or–None Law and the Rate Law. The All–or–None Law states that if an action potential occurs it will continue to the terminal buttons without interruption. The Rate Law, however, describes how the different rates of an action potential represent different stimulus

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