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Questions and Answers
What is the state of voltage-gated sodium channels at rest?
What contributes to the repolarization phase of the action potential?
What triggers the opening of more voltage-gated sodium channels during the action potential?
What causes the sharp rise in membrane potential during the depolarization phase?
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What is the state of voltage-gated sodium channels during the resting state of a neuron?
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What contributes to the repolarization phase of the action potential?
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What triggers the opening of more voltage-gated sodium channels during the action potential?
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What causes the sharp rise in membrane potential during the depolarization phase?
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What contributes to the repolarization phase of the action potential?
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What triggers the opening of more voltage-gated sodium channels during the action potential?
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What causes the sharp rise in membrane potential during the depolarization phase?
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What is the state of voltage-gated sodium channels at rest?
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What is the state of voltage-gated sodium channels during the resting state of a neuron?
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What triggers the opening of more voltage-gated sodium channels during the action potential?
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What contributes to the repolarization phase of the action potential?
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What causes the sharp rise in membrane potential during the depolarization phase?
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What is the role of voltage-gated potassium channels during the repolarization phase?
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What happens to voltage-gated sodium channels after reaching their peak during the action potential?
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What is the effect of depolarization reaching a certain threshold during the action potential?
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What is responsible for maintaining the resting membrane potential in a neuron?
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What is the primary function of voltage-gated sodium channels during depolarization?
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What leads to a decrease in membrane potential during repolarization?
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What triggers the opening of voltage-gated sodium channels during the depolarization phase of the action potential?
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What contributes to the repolarization phase of the action potential?
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What is the state of voltage-gated sodium channels at rest?
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What is responsible for maintaining the resting membrane potential in a neuron?
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Which type of muscle is responsible for involuntary, rhythmic contractions in the body?
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Which type of muscle is primarily under the control of the autonomic nervous system?
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Which type of muscle is attached to bones by tendons and is responsible for voluntary movement?
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Which type of muscle contracts rhythmically to pump blood throughout the body?
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Study Notes
Voltage-Gated Sodium Channels
- At rest, voltage-gated sodium channels are closed, preventing sodium ions from entering the neuron.
- During the resting state, channels are not active and contributing to a stable membrane potential.
Action Potential Phases
- Repolarization phase occurs due to the opening of voltage-gated potassium channels, allowing potassium to exit and restore the negative internal charge.
- When depolarization reaches a certain threshold, it triggers the opening of additional voltage-gated sodium channels, amplifying the action potential.
- Sharp rise in membrane potential during depolarization results from the rapid influx of sodium ions through opened voltage-gated sodium channels.
Role of Voltage-Gated Sodium Channels
- Primary function during depolarization is to facilitate a rapid influx of sodium ions, significantly raising the membrane potential.
- After reaching peak potential, voltage-gated sodium channels become inactivated, stopping sodium ion entry.
Resting Membrane Potential
- The resting membrane potential is primarily maintained by the activity of the sodium-potassium pump, which expels sodium ions and retains potassium ions.
Types of Muscle
- Cardiac muscle is responsible for involuntary, rhythmic contractions that pump blood throughout the body.
- Smooth muscle, controlled by the autonomic nervous system, is found in various organs and also facilitates involuntary movements.
- Skeletal muscle is attached to bones by tendons and responsible for voluntary movements.
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Description
Test your knowledge on the changes in ionic channels during the resting and depolarization phases of a neuron's action potential. Understand the dynamics of voltage-gated sodium and potassium channels in maintaining and altering the membrane potential.
