What cation (positive charged ion) rushes into the cell during depolarization period of action potential?
Question
What cation (positive charged ion) rushes into the cell during depolarization period of action potential?
Solution
The cation that rushes into the cell during the depolarization period of an action potential is Sodium (Na+). Here are the steps explaining the process:
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At rest, the neuron has a negative charge inside relative to the outside. This is due to the distribution of different ions, including Sodium (Na+) and Potassium (K+), across the neuron's membrane.
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When a stimulus is received, voltage-gated Sodium channels open. This means that the channels that were keeping Sodium ions out of the cell now open up.
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Sodium ions, which are positively charged, rush into the cell. This is due to the concentration gradient - there are more Sodium ions outside the cell than inside, so they move into the cell to balance this out.
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The influx of positive Sodium ions makes the inside of the cell more positive, causing the cell to depolarize.
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Once the cell reaches a certain level of depolarization, known as the threshold, an action potential is triggered. This is a rapid, temporary change in the membrane potential.
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After the action potential, the cell repolarizes - it returns to its resting state. This is achieved by the opening of voltage-gated Potassium channels, allowing Potassium ions to leave the cell, and the closing of Sodium channels, preventing more Sodium ions from entering the cell.
Similar Questions
During an action potential of a neuron, the type of ion that enters the cell and causes depolarization is the ion.
Complete the sentences describing the events that occur during an action potential.An action potential will not occur unless the membrane potential at the (the initial segment of the axon) reaches a level called .When threshold is reached, of the initial segment open briefly, allowing to diffuse into the cell.As these ions enter the cell, the cell membrane undergoes , with the membrane potential increasing to a peak of approximately +30mV.As the peak of the action potential is reached, the sodium channels close and the open, allowing these ions to diffuse out of the cell.As cations leave the cell, the membrane potential at that part of the membrane once again becomes negative. This phase of the action potential is called , because the resting membrane potential is being reestablished.The membrane potential actually dips lower than -70mV because the potassium channels do not close quickly enough. This phase is called .
A recently depolarized area of a cell membrane cannot generate an action potential because of theMultiple Choiceabsolute refractory period.high concentration of sodium ions in the extracellular fluid.the high concentration of potassium ions in the cytoplasm.presence of receptor sites on the membrane.
During the depolarisation stage of an action potentialThe membrane potential returns to resting conditionsSodium (Na+) enters the cell down it's concentration gradientVoltage gated K+ channels are openPotassium (K+) enters the cell against its concentration gradient
The inside of the cell membrane becomes negative at the time of an action potential.
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