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A.P. propagation consists of the movement of the action potential along the axon, axon terminals and dendrites. A.P. propagation is non-decremental meaning that the amplitude of the A.P. remains constant throughout the propagation. Action potentials are also follow the principle of all-or-none fashion. Meaning if there is not enough summation(adding of EPSPs and mEPPs) to bring the stimulus to threshold, then no AP will be elicited
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∙ 15y ago
Wiki User
∙ 12y agoHi, i can answer this up to my own A-level knowledge of Biology.
There are two types of neurone, myelinated or unmyelinated.
Firstly i will discuss the transmission of an action potential across a myelinated neurone.
Firstly a stimulus causes an influx of Na+ ions into the axon, this causes more sodium voltage-gated channels to open and so more Na+ ions move down the electrochemical gradient, this causes the axon to depolarise. This depolarisation may cross the threshold value for that neurone and hence induce an action potential. In myelinated neurones there are gaps in the electrical insulating layer of the myelin sheath, these are called nodes of ranvier. Localised currents arise at these nodes and nerve impules (action potentials) effectively 'jump' from node to node, this is called saltatory conduction.
In unmyelinated neurones, the opening of sodium voltage-gated ion channels will open, this causes an adjacent section of the neurone to become depolarised as a localised circuit is created, this process is repeated across the whole length of the neurone, travelling in one direction. This is due to the refractory period, this is where the sodium ion channels are closed breifly as it's repolarised by K+ ions, therefore as they are closed the action potential cannot move backwards, but forwards into a section of the neurone that is at resting potential.
I hope this is ok :)
Wiki User
∙ 7y agoA nerve impulse is an electrical signal that travels along an axon. There is an electrical difference between the inside of the axon and its surroundings, like a tiny battery. When the nerve is activated, there is a sudden change in the voltage across the wall of the axon, caused by the movement of ions in and out of the neuron. This triggers a wave of electrical activity that passes from the cell body along the length of the axon to the synapse.
The speed of nerve impulses varies enormously in different types of neuron. The fastest travel at about 250 mph, faster than a Formula 1 racing car. For the impulse to travel quickly, the axon needs to be thick and well insulated with myelin.
This uses a lot of space and energy, however, and is found only in neurons that need to transfer information urgently.
For example, if you burn your fingers it is important that your brain gets the message to withdraw your hand very quickly.
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∙ 15y agoan action potential (also known as a nerve impulse or spike) is a pulse-like wave of voltage that travels along several types of cell membranes.
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∙ 11y agoAn influx of sodium ions from the current action potential depolarizes the adjacent area
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∙ 16y agoHow is action potential generated
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How fast does an action potential travel down a myelinated nerve?
An action potential is not passively propagated down the axon. There have to be ion channels along the axon or else the action potential will gradually decay. So the the rate of that the action potential 'travels' is dependent on the passive property called the length constant of the axon (factor in capacitance, axon diameter) plus the density of ion channels.
When an action potential is initiated on a nerve cell membrane it radiates and is propagated in all directions from the point of initial stimulation?
Correct. The action potential is initiated at a specific point on the cell membrane called the axon hillock, and it then travels down the axon in one direction. Once initiated, it spreads along the entire length of the axon and can be transmitted to other neurons or muscle cells.
What does an action potential refer to as?
An action potential is basically the message which is sent by the neuron down the axon towards synapse.In other words it is the impulse or the electrical signal that travels along the axon due to difference in the positive and negative charges inside and outside of the axon wall.
Action potential is generated by the movement of?
An action potential is propagated in a neuron through the activation of various voltage-gated and ligand-gated ion channels. Examples include sodium and calcium channels and nicotinic-acetylcholine receptors.
What is the membrane of a nerve cell is comprised of?
Its main function is to propagate the action potential (the 'impulse') along the length of the axon.
How fast does an action potential travel down a myelinated nerve?
An action potential is not passively propagated down the axon. There have to be ion channels along the axon or else the action potential will gradually decay. So the the rate of that the action potential 'travels' is dependent on the passive property called the length constant of the axon (factor in capacitance, axon diameter) plus the density of ion channels.
How far would an action potential propagated in an unmyelinated axon?
The impulse will go to the terminal end of the axon. Other wise the very purpose of the innervation will be defeated.
When an action potential is initiated on a nerve cell membrane it radiates and is propagated in all directions from the point of initial stimulation?
Correct. The action potential is initiated at a specific point on the cell membrane called the axon hillock, and it then travels down the axon in one direction. Once initiated, it spreads along the entire length of the axon and can be transmitted to other neurons or muscle cells.
Conduction along a myelinated axon is called?
It is called saltatory conduction. This describes the "jumping" of an action potential from node to node on a myelinated axon.
How action potential is propagated?
A.P. propagation consists of the movement of the action potential along the axon, axon terminals and dendrites. A.P. propagation is non-decremental meaning that the amplitude of the A.P. remains constant throughout the propagation. Action potentials are also follow the principle of all-or-none fashion. Meaning if there is not enough summation(adding of EPSPs and mEPPs) to bring the stimulus to threshold, then no AP will be elicited
Electrical change in the neuronal membrane that is transmitted along axon is?
Action potential is the term for an electrical change in the neuronal membrane transmitted along an axon. The axon is part of a nerve cell that conducts impulses.
A long structure leaving the cell body that action potential travel along is called the?
It is the Axon
What does an action potential refer to as?
An action potential is basically the message which is sent by the neuron down the axon towards synapse.In other words it is the impulse or the electrical signal that travels along the axon due to difference in the positive and negative charges inside and outside of the axon wall.
Action potential is generated by the movement of?
An action potential is propagated in a neuron through the activation of various voltage-gated and ligand-gated ion channels. Examples include sodium and calcium channels and nicotinic-acetylcholine receptors.
How does the myelin sheath affect the speed of action potential?
Myelin sheath does several things that affect the speed of an action potential.It acts as an insulator around a neuron axon, thereby focusing the propagation of the action potential along the axis of the axon.The action potential "leaps" from one node of Ranvier (the node in between two myelinated segments) to the next, and to the next, and to the next, and so on, faster than the action potential can propagate as a wave along an unmyelinated axon of the same diameter.The regions along a myelinated axon depolarize locally and successively, thus allowing an action potential to travel along an axon using less energy, which in turn allows the neuron to repolarize more quickly, and thus be ready to conduct the next action potential sooner, thereby increasing the overall speed of information transmission.
What is the membrane of a nerve cell is comprised of?
Its main function is to propagate the action potential (the 'impulse') along the length of the axon.
Are action potential and local potential reversible?
Under normal circumstances action potential will proceed unilaterally. An action potential cannot proceed down an axon and depolarize in the reverse direction on the same axon. It must carry information on one axon in one direction and then on another axon in a separate direction. In a lab you can depolarize neurons in the middle of an axon and it will depolarize bilaterally.
