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What ion is responsible for depolarization of the neuron during an action potential?
Wiki User
∙ 13y ago
No single ion in and of itself is responsible for firing an action potential. Instead, 4 total ions are important when talking about excitable cells in general. These include sodium, potassium, calcium, and to a very small extent, chlorine. (chlorine has a role in excitable cells while they are at rest, but not while they are firing action potentials) Sodium and potassium are the main ions involved in changing the membrane potential of an excitable cell, which leads to the firing of an action potential. However, calcium ions are also important in the process. Calcium ions allow vesicles (these are essentially containers of small molecules and ions in the cell) at the end of a cell body to fuse with the cell membrane and release their contents into the outside environment. In this outside environment, the released contents bind with certain receptors on a neighboring cell, which is then depolarized, generating a new action potential. (this is called propagation)
Wiki User
∙ 15y ago
Wiki User
∙ 11y agoNa+ entering the cell through voltage gated sodium channels depolarises the neurone so AP can occur. Technically other stimuli such as synaptic transmition cause depolarisation to open voltage gated Na+ channels but Na+ would be what you are looking for.
Wiki User
∙ 10y agoUsually repolarization phase is the attaining of resting membrane potential (having more negative value of charge inside the membrane than outside of it)back from action membrane potential (having more positive charge inside the membrane than outside the cell).
It occurs from the movement of positively charged potassium ions out of the membrane (cell).
Wiki User
∙ 13y agocalcium
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What is the Difference between a receptor and an action potential?
action potential has a threshold stimulus and depolarization is just change in membrae potential where inside becomes for positive relative to outside. The AP has the ability to actually transmit info over long distance in axons once threshhold stimulus/depolarization is reached
The ions that enter the muscle cell during action potential generation are?
cacium ions
During which period can a second action potential be initiated by a larger than normal stimulus?
This the relative refractory period.
What would happen to a resting membrane potential if the sodium potassium transport pump was blocked?
During depolarization, sodium (Na) rushes into the neuron through Na channels (at the Nodes of Ranvier between the bundles of myelin "insulation"). Less Na in the extracellular fluid would mean there would be less to rush in. So, the neuron would not be depolarized as well. The resting membrane potential would be more positive on the inside.
What does the sodium-potassium exchange pump transfer into and out of the cell during depolarization?
The sodium potassium pump does not function during depolarization, but rather after repolarization. During repolarization, potassium ions flow out of the cell into the extracellular space to reestablish membrane polarity. What the sodium potassium exchange pump does is reestablish the initial ionic concentrations. It does this by exchanging three sodium ions inside the cell for every two potassium ions outside the cell.
Which is the first step in a neuron production of an action potential?
Depolarization is the first event in action potential. During depolarization, the sodium gates open and the membrane depolarizes.
What happens in the neurolemma as the result of an action potential?
It provides insulation to the axons and dendrites during depolarization or action potential.
During depolarization of action potential the outer part of axon becomes?
Negative
What ion is rapidly moving into the cell during the depolarization period of an action potential?
Sodium.A positive ion (cation) that enters the cell (influx) rapidly when the membrane threshold is reached and the voltage gated sodium channels open.This occurs during the rising phase of an action potential, i.e. membrane depolarization beyond the threshold for activation.
What is the primary action during depolarization of an action potential?
Sodium ions flow into the neuron via voltage-gated sodium ion channels, driving the membrane potential into the positive. Beyond the threshold, more sodium ion channels are opened, causing the influx of sodium further downstream, and the process repeats, propagating the action potential down the axon.
What channels are open during depolarization and during repolarization?
During depolarization Na channels are open During repolarization K channels are open
What is the Difference between a receptor and an action potential?
action potential has a threshold stimulus and depolarization is just change in membrae potential where inside becomes for positive relative to outside. The AP has the ability to actually transmit info over long distance in axons once threshhold stimulus/depolarization is reached
What is the interval called during which a neuron is dormant after an action potential has been completed?
Resting potential
What helps maintain the resting potential of a neuron?
During resting potential, the Sodium-Potassium pump is inactive. Therefore, it is indirectly responsible for the resting potential. However, Potassium diffuses outside the membrane via "leakage" channels, and causes the resting potential.
Is the Nernst potential of Sodium achieved during the action potential?
the Nernst potential of Sodium is +60mV. most action potentials do not reach +60mV at peak depoloarization. http://openwetware.org/images/thumb/a/a6/Action-potential.jpg/300px-Action-potential.jpg.png
What are the Stages of nerve impulses?
The action potential has 5 main phases:1) stimulation/rising phase - depolarization caused by influx of sodium ions at the axon hillock; potential increases from a resting potential of -70 mV2) peak phase - depolarization and membrane potential reaches a peak, with sodium channels open maximally, at about +40 mV3) falling phase - potassium channels open in response, causing a subsequent reduction in membrane potential, and the neuron begins to repolarize4) hyperpolarization/undershoot phase - more potassium channels stay open after sodium channels close, causing a hyperpolarization of the neuronal membrane, bringing the potential down below its initial resting potential (below -70 mV)5) refractory phase - potassium channels begin to close, allowing the membrane potential to revert back to the resting potential of -70 mV; during this phase, the probability of the nerve being able to refire is extremely low, thus allowing for a delay between action potentials
What changes occur in the neuron during an action potential?
During an action potential, the neuron undergoes a rapid change in membrane potential as sodium ions rush into the cell, leading to depolarization. Subsequently, potassium ions move out of the cell, repolarizing the membrane back to its resting state. This rapid change in membrane potential allows for the transmission of electrical signals along the neuron.
