Membrane Potential and Ion Movement
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Membrane Potential and Ion Movement

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Questions and Answers

Which equation is used to calculate the membrane potential while considering ion permeability and concentration differences?

  • Goldman-Hodgkin-Katz Equation (correct)
  • Nernst Equation
  • Fick's Law of Diffusion
  • Michaelis-Menten Equation

    • What is the primary role of the Na⁺/K⁺ pump in maintaining the resting potential of a neuron?

  • To balance Cl⁻ concentrations across the membrane
  • To facilitate the entry of K⁺ ions into the cell
  • To establish a negative charge inside the cell (correct)
  • To increase Na⁺ concentration inside the cell

    • How does the Nernst equation contribute to understanding ion motion during action potentials?

  • It measures the rate of ion diffusion across the membrane
  • It calculates the resting potential of the neuron
  • It determines the equilibrium potential for specific ions (correct)
  • It predicts the overall membrane permeability

    • What effect do K⁺ channels have during an action potential?

    <p>They hyperpolarize the membrane, moving it closer to -100 mV</p> Signup and view all the answers

    What is a direct consequence of the chloride ion movement regulated by GABA before birth?

    <p>Inhibition of neuronal excitation</p> Signup and view all the answers

    What is the primary ion responsible for repolarizing the membrane during an action potential?

    <p>K⁺</p> Signup and view all the answers

    What primarily causes the establishment of a negative charge inside a cell during resting potential?

    <p>Na⁺/K⁺ pump expelling more Na⁺ than K⁺ is taken in</p> Signup and view all the answers

    Which factor is crucial in influencing ion movement across the cell membrane besides concentration gradients?

    <p>The electrical gradient across the membrane</p> Signup and view all the answers

    Which equation is used to predict the equilibrium potential for a specific ion across a membrane?

    <p>Nernst Equation</p> Signup and view all the answers

    What occurs when sodium channels open during an action potential?

    <p>The membrane potential rapidly moves towards the equilibrium potential of sodium (+60 mV).</p> Signup and view all the answers

    During an action potential, what is the effect of GABA after birth with respect to chloride levels?

    <p>It allows Cl⁻ to exit the neuron, causing depolarization</p> Signup and view all the answers

    How do ion gradients influence the propagation of an action potential?

    <p>They contribute to local depolarization, ensuring signal propagation.</p> Signup and view all the answers

    How does the Na⁺/K⁺ pump primarily contribute to resting membrane potential?

    <p>By pumping 3 Na⁺ ions out and 2 K⁺ ions in, increasing negative charge inside.</p> Signup and view all the answers

    Which statement best describes the role of sodium ions (Na⁺) in action potentials?

    <p>Na⁺ influx during depolarization leads to action potential generation.</p> Signup and view all the answers

    What effect does an increase in extracellular K⁺ concentration have on the membrane potential?

    <p>The membrane potential depolarizes, becoming less negative.</p> Signup and view all the answers

    What defines the action potential's threshold level?

    <p>The point at which sodium channels begin to open.</p> Signup and view all the answers

    Which ion channel mutation is linked to familial migraine disorders?

    <p>Calcium channels</p> Signup and view all the answers

    Which ion has the greatest driving force for movement across the membrane at resting potential?

    <p>Calcium (Ca²⁺)</p> Signup and view all the answers

    What is the primary role of potassium channels during an action potential?

    <p>They facilitate repolarization by allowing K⁺ ions to flow out.</p> Signup and view all the answers

    What role do chloride ions (Cl⁻) play during the generation and maintenance of membrane potential?

    <p>They help maintain the resting membrane potential by moving in and out of the cell.</p> Signup and view all the answers

    What does the Goldman Equation calculate regarding ion movement?

    <p>It provides the equilibrium potential for multiple ions based on their permeability.</p> Signup and view all the answers

    Which type of ion channel is primarily responsible for the fast initial phase of depolarization during an action potential?

    <p>Voltage-gated Na⁺ channels</p> Signup and view all the answers

    Which channel primarily contributes to the events leading to an action potential?

    <p>Na⁺ channels which trigger depolarization.</p> Signup and view all the answers

    Which statement about Cl⁻ channels is true regarding their function in neurons?

    <p>They are activated by neurotransmitter signals.</p> Signup and view all the answers

    Study Notes

    Membrane Potential Calculation

    • The Goldman-Hodgkin-Katz equation is used to calculate membrane potential considering both ion permeability and concentration differences.

    Ion Movement Across Cell Membrane

    • Electrical gradient: Ions move from areas of high electrical charge to areas of low electrical charge.
    • Concentration gradient: Ions move from areas of high concentration to areas of low concentration.

    Oxytocin and Chloride Levels

    • During birth, oxytocin increases the intracellular concentration of chloride ions by activating chloride pumps.
    • This contributes to the increase in membrane potential during labor.

    Nernst Equation

    • The Nernst equation calculates the equilibrium potential of an ion based on its concentration gradient.
    • Variables included in the formula:
      • Ion concentration inside the cell
      • Ion concentration outside the cell
      • Temperature
      • Faraday's constant
      • Gas constant

    Ion Channels and Their Functions

    • Na⁺ channels: Crucial for action potential depolarization.
    • K⁺ channels: Important for resting membrane potential.
    • Ca²⁺ channels: Involved in the release of neurotransmitters at synapses.
    • Cl⁻ channels: Essential for hyperpolarization.
    • Neurotransmitter receptor channels: Activated by chemical ligands like GABA.

    Na⁺/K⁺ Pump

    • The Na⁺/K⁺ pump maintains a negative charge inside the cell by pumping 3 Na⁺ ions out and 2 K⁺ ions in.

    Extracellular K⁺ Concentration Increase

    • An increase in extracellular K⁺ concentration leads to membrane depolarization.

    Driving Force at Resting Potential

    • Calcium (Ca²⁺) has the largest driving force across the membrane at resting potential due to its low intracellular concentration.

    Sodium Channels and Action Potential

    • When sodium channels open during an action potential, the membrane potential rapidly moves towards the equilibrium potential of sodium (+60 mV).

    Resting Membrane Potential

    • The resting membrane potential of neurons is typically negative.

    Oxytocin and Chloride Pumps

    • During birth, oxytocin does not activate chloride pumps, increasing the intracellular concentration of Cl⁻.

    Na⁺/K⁺ Pump Role

    • The Na⁺/K⁺ pump maintains the resting membrane potential by pumping 3 Na⁺ ions out of the cell and 2 K⁺ ions into the cell.

    Ion Channel Mutations and Diseases

    • Ion channel mutations can lead to diseases like cystic fibrosis and migraines.

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    Related Documents

    Neurophysiology Ion Channels Past Paper PDF

    Description

    Explore the concepts of membrane potential calculations using the Goldman-Hodgkin-Katz and Nernst equations. Understand how oxytocin regulates chloride levels during childbirth and its impact on membrane potential. Test your knowledge on ion movement across cell membranes influenced by electrical and concentration gradients.

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