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Is creation of an action potential part of the procsee of nerve conduction along an axon?
Wiki User
∙ 14y ago
Indeed. You have saltatory conduction because of the presence of myelin in peripheral nerves, laid by Schwann cells.
How AP is generated is via the following:
WHen threshold potential is reached , voltage gated Na+ channels open, allowing huge Na+ influx. THis is called rapid depolarization. This is followed by a plateau phase, where the membrane potential is relatively flat because slow Ca2+ influx equalizes K+ efflux.
The last thing is repolarization which is going to a negative membrane potential because more K+ channels open, Ca2+ channels closing and Na/K+ pump (Na+ pumped out, K+ in)
Wiki User
∙ 14y ago
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Which type of axon will velocity of action potential conduction be the fastest?
Myelinated axons with the largest diameter
What does a conduction velocity of an action potential depend on?
An action potential does not have a conduction velocity. Rather, it makes sense to measure the conduction velocity of nerves or nerve cells and this is usually done in metres per second (m/s.). An action potential is characterised as "an all or none response". This means you cannot alter the characteristics of an action potential in a given nerve cell. If you get a nerve cell and manage to get it to threshold, produce and measure an action potential 1000 times or more at the exact same point on the cell, the action potential you measure will not change in timing or amplitude. Information travels down a nerve cell through action potentials. But it is not one action potential that travels the whole length of the axon. Instead what happens is that one action potential causes the next bit of the nerve cell to reach threshold and therefore creates an entirely new action potential. So you actually need multiple action potentials to happen along a nerve cell to send information down it. We call this "propagation of action potentials" since each action potential produces a new one. More properly, it is referred to as "saltatory action potential conduction". Conduction velocity is basically a measure of how quickly we can produce a series of action potentials to travel the distance of the nerve cell axon. Since action potentials only happen at each "Node of Ranvier", then the longer the distance between each node (internodal distance), the faster the conduction velocity of a nerve cell. Since the internodal distance is positively correlated with myelin thickness, more thickly myelinated nerve cells have faster conduction velocities. The thickest and fastest nerve cells are motor neurones and Ia fibres from muscle spindles with a diameter of 12-20 micrometres and a conduction velocity of 70-120 m/s. The thinnest/slowest are fibres used to convey slow pain (<1.5 micrometres and 0.5-2 m/s).
What is the node-to-node jumping regeneration of an action potential along a myelinated axon called?
saltatory conduction Saltatory conduction is derived from the Latin word saltare, which means leaping
What structure in the neuron helps to speed up the transmission of the action potential?
To speed up transmission of the action potential from where it originates (axon hillock) to where it ends (axon terminal), the action potential propagates by 'saltatory conduction' - and the structure that makes this possible is the insulating layer of myelin sheath that wraps around the axon, arranged in 'nodes' along its length. Technically, it's the gaps between the nodes (nodes of Ranvier) that cause the action to continually propagate and maintain its fast conduction velocity.
Why myelin increase impulse conduction speed?
Propagation of an action potential down an axon has both a passive and an active component. The active component is the voltage activated opening of ion channels, but the passive so-called 'cable' properties of the axon also play a role. In a myelinated axon the ion channels are concentrated in the non-mylenated internodes. Current spreads with less loss of potential where there is mylein and this causes the action potential to leap from internode to internode. This is called saltory conduction.
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.
What will increase the rate of conduction of an action potential along a nerve?
Myelinating the nerve
Which of the following would have the fastest conduction of an action potential?
myelinated, large diameter fibres
Which nerve shortens the conduction time of an action potential through the AV node?
vagalstimulation
What would be the effect on action potential conduction at a region of axon where the disease had its effect?
Depends on disease
Which type of axon will velocity of action potential conduction be the fastest?
Myelinated axons with the largest diameter
What does a conduction velocity of an action potential depend on?
An action potential does not have a conduction velocity. Rather, it makes sense to measure the conduction velocity of nerves or nerve cells and this is usually done in metres per second (m/s.). An action potential is characterised as "an all or none response". This means you cannot alter the characteristics of an action potential in a given nerve cell. If you get a nerve cell and manage to get it to threshold, produce and measure an action potential 1000 times or more at the exact same point on the cell, the action potential you measure will not change in timing or amplitude. Information travels down a nerve cell through action potentials. But it is not one action potential that travels the whole length of the axon. Instead what happens is that one action potential causes the next bit of the nerve cell to reach threshold and therefore creates an entirely new action potential. So you actually need multiple action potentials to happen along a nerve cell to send information down it. We call this "propagation of action potentials" since each action potential produces a new one. More properly, it is referred to as "saltatory action potential conduction". Conduction velocity is basically a measure of how quickly we can produce a series of action potentials to travel the distance of the nerve cell axon. Since action potentials only happen at each "Node of Ranvier", then the longer the distance between each node (internodal distance), the faster the conduction velocity of a nerve cell. Since the internodal distance is positively correlated with myelin thickness, more thickly myelinated nerve cells have faster conduction velocities. The thickest and fastest nerve cells are motor neurones and Ia fibres from muscle spindles with a diameter of 12-20 micrometres and a conduction velocity of 70-120 m/s. The thinnest/slowest are fibres used to convey slow pain (<1.5 micrometres and 0.5-2 m/s).
Is the axon the conduction component of a neuron?
Yes, the axon conducts the action potential from the cell body to the effector organ.
What is the node-to-node jumping regeneration of an action potential along a myelinated axon called?
saltatory conduction Saltatory conduction is derived from the Latin word saltare, which means leaping
What structure in the neuron helps to speed up the transmission of the action potential?
To speed up transmission of the action potential from where it originates (axon hillock) to where it ends (axon terminal), the action potential propagates by 'saltatory conduction' - and the structure that makes this possible is the insulating layer of myelin sheath that wraps around the axon, arranged in 'nodes' along its length. Technically, it's the gaps between the nodes (nodes of Ranvier) that cause the action to continually propagate and maintain its fast conduction velocity.
Why myelin increase impulse conduction speed?
Propagation of an action potential down an axon has both a passive and an active component. The active component is the voltage activated opening of ion channels, but the passive so-called 'cable' properties of the axon also play a role. In a myelinated axon the ion channels are concentrated in the non-mylenated internodes. Current spreads with less loss of potential where there is mylein and this causes the action potential to leap from internode to internode. This is called saltory conduction.
What is automaticity of the heart?
The property that allows any cell in the cardiac muscle to begin an action potential, or a cardiac conduction, leading to cardiac contraction.
