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When depolarization occurs, sodium ions (Na+) rapidly flood into the cell through voltage-gated sodium channels. This influx of positively charged sodium ions causes the membrane potential to become more positive, moving toward a threshold that triggers further action potentials. As the inside of the cell becomes less negative, it initiates the process of nerve signal transmission or muscle contraction, depending on the cell type. Ultimately, this rapid change in membrane potential is essential for the propagation of electrical signals in neurons and muscle cells.
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What characterizes depolarization the first phase of the action potential?
Depolarization is the initial phase of the action potential characterized by a rapid influx of sodium ions into the cell, causing a change in membrane potential from negative to positive. This occurs when voltage-gated sodium channels open in response to a threshold stimulus, leading to the depolarization of the cell membrane.
Which electrolyte flows into the cell to initiate depolarization?
potassium The answer of potassium is dead wrong. Sodium is the electrolyte that flows into the cell to initiate depolarization. Potassium flows into the cell during repolarization.
Depolarization of the nerve membrane begins with?
The opening of voltage-gated sodium channels in response to a stimulus. Sodium ions flow into the cell, causing depolarization as the inside becomes more positively charged.
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 has the function of transmitting a muscle impulse into the interior of the cell?
Transmitting a muscle impulse into the interior of the cell involves depolarization of the cell membrane through the opening of voltage-gated sodium channels, allowing sodium ions to rush into the cell. This depolarization then triggers the release of calcium ions from the sarcoplasmic reticulum, leading to muscle contraction.
What cell structure is used to prepare for depolarization?
The cell structure used to prepare for depolarization is the sodium-potassium pump, which actively transports sodium out of the cell and potassium into the cell to establish the necessary concentration gradients for depolarization to occur.
What ion is the rising phase of the action potential?
Sodium ions are responsible for the rising phase of the action potential. This occurs when sodium channels open and sodium ions flow into the cell, causing depolarization.
What characterizes depolarization the first phase of the action potential?
Depolarization is the initial phase of the action potential characterized by a rapid influx of sodium ions into the cell, causing a change in membrane potential from negative to positive. This occurs when voltage-gated sodium channels open in response to a threshold stimulus, leading to the depolarization of the cell membrane.
Which electrolyte flows into the cell to initiate depolarization?
potassium The answer of potassium is dead wrong. Sodium is the electrolyte that flows into the cell to initiate depolarization. Potassium flows into the cell during repolarization.
The interior of the cell becomes less negative due to an influx of sodium ions?
The influx of sodium ions causes depolarization of the cell membrane, making the interior less negative. This depolarization can trigger the opening of voltage-gated ion channels, leading to the propagation of an action potential. Sodium-potassium pumps work to restore the original ion concentrations, repolarizing the cell.
Describe the action of depolarization and repolarization?
Depolarization is the process where the membrane potential becomes less negative, moving towards zero or even becoming positive. This occurs when sodium ions rush into the cell. Repolarization is the return of the membrane potential back to its resting state, following depolarization, usually through the efflux of potassium ions from the cell.
Depolarization of the nerve membrane begins with?
The opening of voltage-gated sodium channels in response to a stimulus. Sodium ions flow into the cell, causing depolarization as the inside becomes more positively charged.
Which cellular gates open in depolarization?
In depolarization, voltage-gated sodium channels open first, allowing sodium ions into the cell, resulting in action potential generation. This is followed by voltage-gated potassium channels opening to repolarize the cell.
What are the two ions that are responsible for the initial depolarization of cardiac muscles as they travel from the outside of a muscle cell to the inside of the cell?
The two ions responsible for the initial depolarization of cardiac muscle cells are sodium (Na⁺) and calcium (Ca²⁺). When an action potential is initiated, sodium channels open, allowing sodium ions to rush into the cell, leading to depolarization. Subsequently, calcium channels open, allowing calcium ions to enter, further contributing to the depolarization and facilitating the contraction of the cardiac muscle.
What does the sodium-potassium exchange pump transfer into and out of the cell during depolarization?
The sodium-potassium exchange pump transfers 3 sodium ions out of the cell and 2 potassium ions into the cell during depolarization. This process helps in maintaining the electrochemical gradient across the cell membrane and is crucial for cell function.
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 causes rapid depolarization phase of a pacemaker cell?
Rapid depolarization happens after the membrane threshold has been reached and Na+ ions start to flow into the cell. As more Na+ ions flood in the cell becomes more and more positive. This causes the voltage gated Na+ channels to open creating a flood of Na+ ions and thus a rapid phase of depolarization. Shortly after this rapid phase K+ ions are released from the cell causing the cell to become more negative closing the Na+ channels and thus repolarizing the cell.
