Action potential - Revision history

Prab at 20:11, 18 February 2025

2025-02-18T20:11:32Z

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 An '''action potential''' is a rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane with a characteristic pattern. Action potentials occur in several types of animal cells, called [[excitable cells]], which include [[neurons]], [[muscle cells]], and [[endocrine cells]], as well as in some plant cells.
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 [[Category:Electrophysiology]]
 [[Category:Neurophysiology]]

Prab: Undo revision 6328556 by Prab (talk)

2025-02-18T20:10:45Z

Undo revision 6328556 by Prab (talk)

← Older revision		Revision as of 20:10, 18 February 2025
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	~~{{Short description\|A brief overview of action potentials in neuroscience}}~~		Action potential

	~~==Action Potential==~~		An '''action potential''' is a rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane with a characteristic pattern. Action potentials occur in several types of animal cells, called [[excitable cells]], which include [[neurons]], [[muscle cells]], and [[endocrine cells]], as well as in some plant cells.
	An '''action potential''' is a rapid~~, temporary change~~ in a ~~cell's~~ membrane ~~potential, which is~~ a ~~fundamental mechanism by which neurons communicate~~. Action potentials ~~are essential for the functioning~~ of ~~the nervous system~~, ~~allowing for the transmission of signals over long distances within the body~~.

	[[~~File:Neuron action potential.svg\|thumb\|right\|Diagram~~ of ~~an action potential in~~ a neuron.]]		==Overview==
			An action potential is a fundamental feature of the [[nervous system]] and is essential for the propagation of signals along the [[axon]] of a [[neuron]]. It is a transient event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory.

	==~~=Overview=~~==		==Phases of an Action Potential==
	Action potentials occur in the [[axon]]s of [[neurons]] and are initiated when a neuron receives a sufficient [[stimulus]] to depolarize its membrane to a critical threshold. This depolarization is followed by a rapid rise in membrane potential, a peak, and then a return to the resting potential.

	===~~Phases of an Action~~ Potential===		===Resting Potential===
			The [[resting potential]] is the baseline state of the neuron, typically around -70 mV. This is maintained by the [[sodium-potassium pump]] and the differential permeability of the membrane to [[sodium]] and [[potassium]] ions.

	===~~=Resting Potential=~~===		===Depolarization===
	~~The resting potential is the baseline state of a neuron~~, ~~typically around -70 mV. This potential is maintained by the~~ [[sodium~~-potassium pump~~]] ~~and~~ the ~~differential permeability of~~ the membrane to ~~[[sodium]] and [[potassium]] ions~~.		During depolarization, [[voltage-gated sodium channels]] open, allowing sodium ions to flow into the cell. This causes the membrane potential to become more positive.

	===~~=Depolarization=~~===		===Repolarization===
	~~When a neuron is stimulated,~~ [[voltage-gated ~~sodium~~ channels]] open, allowing ~~sodium~~ ions to ~~rush into~~ the cell~~. This influx of positive ions causes~~ the membrane potential to ~~become less~~ negative~~, leading to depolarization~~.		Repolarization occurs when the sodium channels close and [[voltage-gated potassium channels]] open, allowing potassium ions to flow out of the cell, returning the membrane potential to a negative value.

	===~~=Repolarization=~~===		===Hyperpolarization===
	~~Following depolarization, [[voltage-gated potassium channels]] open, allowing potassium ions to flow out of~~ the ~~cell~~. This efflux of ~~positive~~ ions ~~helps to return the membrane potential to a more negative value~~.		Hyperpolarization is a phase where the membrane potential becomes more negative than the resting potential. This is due to the continued efflux of potassium ions.

	===~~=Hyperpolarization=~~===		===Refractory Period===
	The ~~membrane~~ potential ~~temporarily becomes more negative than~~ the ~~resting potential due to~~ the ~~continued efflux of potassium ions. This phase is known as hyperpolarization~~.		The [[refractory period]] is a period of time during which a neuron is unable to fire another action potential. It consists of the absolute refractory period and the relative refractory period.

	==~~==Return to Resting Potential==~~==		==Propagation of Action Potentials==
	~~The sodium-potassium pump and other ion channels restore~~ the ~~resting potential~~, ~~preparing the neuron for~~ the ~~next~~ action potential.		Action potentials propagate along the axon of a neuron. In [[myelinated axons]], the action potential jumps between [[nodes of Ranvier]] in a process called [[saltatory conduction]]. This increases the speed of transmission.

	==~~=Propagation of Action Potentials=~~==		==Role in Synaptic Transmission==
	Action potentials ~~propagate along the axon of~~ a ~~neuron~~. ~~In myelinated axons, this propagation occurs via~~ [[~~saltatory conduction~~]], ~~where~~ the ~~action potential "jumps" from one~~ [[~~node of Ranvier~~]] to the ~~next~~, ~~increasing~~ the ~~speed of transmission~~.		Action potentials play a crucial role in [[synaptic transmission]]. When an action potential reaches the [[axon terminal]], it triggers the release of [[neurotransmitters]] into the [[synaptic cleft]], which then bind to receptors on the [[postsynaptic neuron]].

	[[~~File:Saltatory conduction.svg\|thumb\|left\|Illustration~~ of ~~saltatory conduction~~ in ~~a myelinated axon.~~]]		==Pacemaker Potentials==
			[[Pacemaker potentials]] are spontaneous depolarizations that occur in certain types of cells, such as those in the [[sinoatrial node]] of the heart. These potentials are responsible for initiating the rhythmic contractions of the heart.

	~~===Refractory Periods===~~		==Related pages==
	~~The refractory period is a time during which a neuron is unable to fire another action potential. It consists of two phases:~~

	* '''Absolute refractory period''': No new action potential can be initiated, regardless of the strength of the stimulus.
	* '''Relative refractory period''': A stronger-than-normal stimulus is required to initiate an action potential.

	~~==Significance in the Nervous System==~~
	Action potentials are crucial for the functioning of the [[central nervous system]] and the [[peripheral nervous system]]. They enable the rapid transmission of signals necessary for [[muscle contraction]], [[sensory perception]], and [[cognitive processes]].

	==Related ~~Pages~~==
	* [[Neuron]]		* [[Neuron]]
	* [[Synapse]]		* [[Synapse]]
	* [[~~Neurotransmitter~~]]		* [[Myelin]]
	* [[Electrophysiology]]		* [[Electrophysiology]]

	~~[[Category~~:~~Neuroscience]]~~		==Gallery==
			<gallery>
			File:Action_Potential.gif\|Animation of an action potential.
			File:Action_potential_basic_shape.svg\|Basic shape of an action potential.
			File:Action_potential.svg\|Graph of an action potential.
			File:Blausen_0011_ActionPotential_Nerve.png\|Illustration of action potential in a nerve.
			File:Membrane_Permeability_of_a_Neuron_During_an_Action_Potential.svg\|Membrane permeability during an action potential.
			File:SynapseSchematic_en.svg\|Diagram of a synapse.
			File:Pacemaker_potential.svg\|Graph of a pacemaker potential.
			File:Neuron1.jpg\|Image of a neuron.
			File:Conduction_velocity_and_myelination.png\|Conduction velocity and myelination.
			File:Cable_theory_Neuron_RC_circuit_v3.svg\|Cable theory in neurons.
			File:Gap_cell_junction-en.svg\|Gap junctions in cells.
			</gallery>

	[[Category:Electrophysiology]]		[[Category:Electrophysiology]]
			[[Category:Neurophysiology]]
			<gallery>
			File:Action_Potential.gif\|Action potential
			File:Action_potential_basic_shape.svg\|Action potential
			File:Action_potential.svg\|Action potential
			File:Blausen_0011_ActionPotential_Nerve.png\|Action potential
			File:Membrane_Permeability_of_a_Neuron_During_an_Action_Potential.svg\|Action potential
			File:SynapseSchematic_en.svg\|Action potential
			File:Pacemaker_potential.svg\|Action potential
			File:Neuron1.jpg\|Action potential
			File:Conduction_velocity_and_myelination.png\|Action potential
			File:Cable_theory_Neuron_RC_circuit_v3.svg\|Action potential
			File:Gap_cell_junction-en.svg\|Action potential
			File:Ventricular_myocyte_action_potential.svg\|Action potential
			</gallery>

Prab: CSV import

2025-02-18T17:33:14Z

CSV import

← Older revision		Revision as of 17:33, 18 February 2025
Line 1:		Line 1:
	~~Action potential~~		{{Short description\|A brief overview of action potentials in neuroscience}}

	An '''action potential''' is a rapid ~~rise and subsequent fall~~ in ~~voltage or~~ membrane potential ~~across~~ a ~~cellular membrane with a characteristic pattern~~. Action potentials ~~occur in several types~~ of ~~animal cells~~, ~~called [[excitable cells]], which include [[neurons]], [[muscle cells]], and [[endocrine cells]], as well as in some plant cells~~.		==Action Potential==
			An '''action potential''' is a rapid, temporary change in a cell's membrane potential, which is a fundamental mechanism by which neurons communicate. Action potentials are essential for the functioning of the nervous system, allowing for the transmission of signals over long distances within the body.

	~~==Overview==~~		[[File:Neuron action potential.svg\|thumb\|right\|Diagram of an action potential in a neuron.]]
	An action potential ~~is a fundamental feature of the [[nervous system]] and is essential for the propagation of signals along the [[axon]]~~ of a [[neuron]]~~. It is a transient event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory.~~

	==~~Phases of an Action Potential~~==		===Overview===
			Action potentials occur in the [[axon]]s of [[neurons]] and are initiated when a neuron receives a sufficient [[stimulus]] to depolarize its membrane to a critical threshold. This depolarization is followed by a rapid rise in membrane potential, a peak, and then a return to the resting potential.

	===~~Resting~~ Potential===		===Phases of an Action Potential===
	The [[resting potential]] is the baseline state of the neuron, typically around -70 mV. This is maintained by the [[sodium-potassium pump]] and the differential permeability of the membrane to [[sodium]] and [[potassium]] ions.

	===~~Depolarization~~===		====Resting Potential====
	~~During depolarization~~, [[~~voltage~~-~~gated sodium channels~~]] ~~open, allowing sodium ions to flow into~~ the ~~cell. This causes~~ the membrane ~~potential~~ to ~~become more positive~~.		The resting potential is the baseline state of a neuron, typically around -70 mV. This potential is maintained by the [[sodium-potassium pump]] and the differential permeability of the membrane to [[sodium]] and [[potassium]] ions.

	===~~Repolarization~~===		====Depolarization====
	~~Repolarization occurs when the sodium channels close and~~ [[voltage-gated ~~potassium~~ channels]] open, allowing ~~potassium~~ ions to ~~flow out of~~ the cell~~, returning~~ the membrane potential to a negative ~~value~~.		When a neuron is stimulated, [[voltage-gated sodium channels]] open, allowing sodium ions to rush into the cell. This influx of positive ions causes the membrane potential to become less negative, leading to depolarization.

	===~~Hyperpolarization~~===		====Repolarization====
	~~Hyperpolarization is a phase where the membrane potential becomes more negative than~~ the ~~resting potential~~. This ~~is due to the continued~~ efflux of ~~potassium~~ ions.		Following depolarization, [[voltage-gated potassium channels]] open, allowing potassium ions to flow out of the cell. This efflux of positive ions helps to return the membrane potential to a more negative value.

	===~~Refractory Period~~===		====Hyperpolarization====
	The ~~[[refractory period]] is a period of time during which a neuron is unable to fire another action~~ potential~~. It consists of~~ the ~~absolute refractory period and~~ the ~~relative refractory period~~.		The membrane potential temporarily becomes more negative than the resting potential due to the continued efflux of potassium ions. This phase is known as hyperpolarization.

	==~~Propagation of Action Potentials~~==		====Return to Resting Potential====
	~~Action potentials propagate along~~ the ~~axon of a~~ neuron~~. In [[myelinated axons]],~~ the action potential ~~jumps between [[nodes of Ranvier]] in a process called [[saltatory conduction]]. This increases the speed of transmission~~.		The sodium-potassium pump and other ion channels restore the resting potential, preparing the neuron for the next action potential.

	==~~Role in Synaptic Transmission~~==		===Propagation of Action Potentials===
	Action potentials ~~play~~ a ~~crucial role in~~ [[~~synaptic transmission~~]]~~. When an~~ action potential ~~reaches the~~ [[~~axon terminal]], it triggers the release~~ of ~~[[neurotransmitters~~]] ~~into~~ the ~~[[synaptic cleft]]~~, ~~which then bind to receptors on~~ the ~~[[postsynaptic neuron]]~~.		Action potentials propagate along the axon of a neuron. In myelinated axons, this propagation occurs via [[saltatory conduction]], where the action potential "jumps" from one [[node of Ranvier]] to the next, increasing the speed of transmission.

	~~==Pacemaker Potentials==~~		[[File:Saltatory conduction.svg\|thumb\|left\|Illustration of saltatory conduction in a myelinated axon.]]
	[[~~Pacemaker potentials]] are spontaneous depolarizations that occur in certain types~~ of ~~cells, such as those~~ in ~~the [[sinoatrial node~~]] ~~of the heart. These potentials are responsible for initiating the rhythmic contractions of the heart.~~

	==Related ~~pages~~==		===Refractory Periods===
			The refractory period is a time during which a neuron is unable to fire another action potential. It consists of two phases:

			* '''Absolute refractory period''': No new action potential can be initiated, regardless of the strength of the stimulus.
			* '''Relative refractory period''': A stronger-than-normal stimulus is required to initiate an action potential.

			==Significance in the Nervous System==
			Action potentials are crucial for the functioning of the [[central nervous system]] and the [[peripheral nervous system]]. They enable the rapid transmission of signals necessary for [[muscle contraction]], [[sensory perception]], and [[cognitive processes]].

			==Related Pages==
	* [[Neuron]]		* [[Neuron]]
	* [[Synapse]]		* [[Synapse]]
	* [[~~Myelin~~]]		* [[Neurotransmitter]]
	* [[Electrophysiology]]		* [[Electrophysiology]]

	~~==Gallery==~~		[[Category:Neuroscience]]
	~~<gallery>~~
	~~File~~:~~Action_Potential.gif\|Animation of an action potential.~~
	~~File:Action_potential_basic_shape.svg\|Basic shape of an action potential.~~
	~~File:Action_potential.svg\|Graph of an action potential.~~
	~~File:Blausen_0011_ActionPotential_Nerve.png\|Illustration of action potential in a nerve.~~
	~~File:Membrane_Permeability_of_a_Neuron_During_an_Action_Potential.svg\|Membrane permeability during an action potential.~~
	~~File:SynapseSchematic_en.svg\|Diagram of a synapse.~~
	~~File:Pacemaker_potential.svg\|Graph of a pacemaker potential.~~
	~~File:Neuron1.jpg\|Image of a neuron.~~
	~~File:Conduction_velocity_and_myelination.png\|Conduction velocity and myelination.~~
	~~File:Cable_theory_Neuron_RC_circuit_v3.svg\|Cable theory in neurons.~~
	~~File:Gap_cell_junction-en.svg\|Gap junctions in cells.~~
	~~</gallery>~~

	[[Category:Electrophysiology]]		[[Category:Electrophysiology]]
	~~[[Category:Neurophysiology]]~~
	~~<gallery>~~
	~~File:Action_Potential.gif\|Action potential~~
	~~File:Action_potential_basic_shape.svg\|Action potential~~
	~~File:Action_potential.svg\|Action potential~~
	~~File:Blausen_0011_ActionPotential_Nerve.png\|Action potential~~
	~~File:Membrane_Permeability_of_a_Neuron_During_an_Action_Potential.svg\|Action potential~~
	~~File:SynapseSchematic_en.svg\|Action potential~~
	~~File:Pacemaker_potential.svg\|Action potential~~
	~~File:Neuron1.jpg\|Action potential~~
	~~File:Conduction_velocity_and_myelination.png\|Action potential~~
	~~File:Cable_theory_Neuron_RC_circuit_v3.svg\|Action potential~~
	~~File:Gap_cell_junction-en.svg\|Action potential~~
	~~File:Ventricular_myocyte_action_potential.svg\|Action potential~~
	~~</gallery>~~

Prab: CSV import

2025-02-18T12:10:32Z

CSV import

← Older revision		Revision as of 12:10, 18 February 2025
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	[[Category:Electrophysiology]]		[[Category:Electrophysiology]]
	[[Category:Neurophysiology]]		[[Category:Neurophysiology]]
			<gallery>
			File:Action_Potential.gif\|Action potential
			File:Action_potential_basic_shape.svg\|Action potential
			File:Action_potential.svg\|Action potential
			File:Blausen_0011_ActionPotential_Nerve.png\|Action potential
			File:Membrane_Permeability_of_a_Neuron_During_an_Action_Potential.svg\|Action potential
			File:SynapseSchematic_en.svg\|Action potential
			File:Pacemaker_potential.svg\|Action potential
			File:Neuron1.jpg\|Action potential
			File:Conduction_velocity_and_myelination.png\|Action potential
			File:Cable_theory_Neuron_RC_circuit_v3.svg\|Action potential
			File:Gap_cell_junction-en.svg\|Action potential
			File:Ventricular_myocyte_action_potential.svg\|Action potential
			</gallery>

Prab: CSV import

2025-02-11T21:57:15Z

CSV import

New page

Action potential

An '''action potential''' is a rapid rise and subsequent fall in voltage or membrane potential across a cellular membrane with a characteristic pattern. Action potentials occur in several types of animal cells, called [[excitable cells]], which include [[neurons]], [[muscle cells]], and [[endocrine cells]], as well as in some plant cells.

==Overview==
An action potential is a fundamental feature of the [[nervous system]] and is essential for the propagation of signals along the [[axon]] of a [[neuron]]. It is a transient event in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory.

==Phases of an Action Potential==

===Resting Potential===
The [[resting potential]] is the baseline state of the neuron, typically around -70 mV. This is maintained by the [[sodium-potassium pump]] and the differential permeability of the membrane to [[sodium]] and [[potassium]] ions.

===Depolarization===
During depolarization, [[voltage-gated sodium channels]] open, allowing sodium ions to flow into the cell. This causes the membrane potential to become more positive.

===Repolarization===
Repolarization occurs when the sodium channels close and [[voltage-gated potassium channels]] open, allowing potassium ions to flow out of the cell, returning the membrane potential to a negative value.

===Hyperpolarization===
Hyperpolarization is a phase where the membrane potential becomes more negative than the resting potential. This is due to the continued efflux of potassium ions.

===Refractory Period===
The [[refractory period]] is a period of time during which a neuron is unable to fire another action potential. It consists of the absolute refractory period and the relative refractory period.

==Propagation of Action Potentials==
Action potentials propagate along the axon of a neuron. In [[myelinated axons]], the action potential jumps between [[nodes of Ranvier]] in a process called [[saltatory conduction]]. This increases the speed of transmission.

==Role in Synaptic Transmission==
Action potentials play a crucial role in [[synaptic transmission]]. When an action potential reaches the [[axon terminal]], it triggers the release of [[neurotransmitters]] into the [[synaptic cleft]], which then bind to receptors on the [[postsynaptic neuron]].

==Pacemaker Potentials==
[[Pacemaker potentials]] are spontaneous depolarizations that occur in certain types of cells, such as those in the [[sinoatrial node]] of the heart. These potentials are responsible for initiating the rhythmic contractions of the heart.

==Related pages==
* [[Neuron]]
* [[Synapse]]
* [[Myelin]]
* [[Electrophysiology]]

==Gallery==
<gallery>
File:Action_Potential.gif|Animation of an action potential.
File:Action_potential_basic_shape.svg|Basic shape of an action potential.
File:Action_potential.svg|Graph of an action potential.
File:Blausen_0011_ActionPotential_Nerve.png|Illustration of action potential in a nerve.
File:Membrane_Permeability_of_a_Neuron_During_an_Action_Potential.svg|Membrane permeability during an action potential.
File:SynapseSchematic_en.svg|Diagram of a synapse.
File:Pacemaker_potential.svg|Graph of a pacemaker potential.
File:Neuron1.jpg|Image of a neuron.
File:Conduction_velocity_and_myelination.png|Conduction velocity and myelination.
File:Cable_theory_Neuron_RC_circuit_v3.svg|Cable theory in neurons.
File:Gap_cell_junction-en.svg|Gap junctions in cells.
</gallery>

[[Category:Electrophysiology]]
[[Category:Neurophysiology]]

← Older revision		Revision as of 12:10, 18 February 2025
Line 55:		Line 55:
	[[Category:Electrophysiology]]		[[Category:Electrophysiology]]
	[[Category:Neurophysiology]]		[[Category:Neurophysiology]]
			<gallery>
			File:Action_Potential.gif\|Action potential
			File:Action_potential_basic_shape.svg\|Action potential
			File:Action_potential.svg\|Action potential
			File:Blausen_0011_ActionPotential_Nerve.png\|Action potential
			File:Membrane_Permeability_of_a_Neuron_During_an_Action_Potential.svg\|Action potential
			File:SynapseSchematic_en.svg\|Action potential
			File:Pacemaker_potential.svg\|Action potential
			File:Neuron1.jpg\|Action potential
			File:Conduction_velocity_and_myelination.png\|Action potential
			File:Cable_theory_Neuron_RC_circuit_v3.svg\|Action potential
			File:Gap_cell_junction-en.svg\|Action potential
			File:Ventricular_myocyte_action_potential.svg\|Action potential
			</gallery>