Skip to main content
Back

Membrane Potential and Ion Gradients in Neurons

Control buttons has been changed to "navigation" mode.
1/20

Terms in this set (20)

  • What is membrane potential?

    Membrane potential is the electrical voltage difference across a cell's plasma membrane caused by the distribution of ions.

  • Define electrical gradient.

    An electrical gradient is the difference in charge across a membrane that influences ion movement.

  • What is a chemical gradient?

    A chemical gradient is the difference in ion concentration across a membrane that drives ions from high to low concentration.

  • Explain electrochemical gradient.

    The electrochemical gradient combines both electrical and chemical gradients to determine ion movement across membranes.

  • What is a leak channel?

    A leak channel is an ion channel that is always open, allowing ions to move down their electrochemical gradient.

  • Define ligand-gated channel.

    A ligand-gated channel opens in response to a specific chemical binding to it, allowing ions to pass.

  • What is a voltage-gated channel?

    A voltage-gated channel opens or closes in response to changes in membrane potential.

  • Define equilibrium potential.

    Equilibrium potential is the membrane voltage at which there is no net movement of a specific ion across the membrane.

  • What is resting membrane potential?

    Resting membrane potential is the stable voltage of a neuron at rest, typically around -70 mV.

  • Describe the relative concentration of Na+ inside and outside the cell.

    Na+ concentration is higher outside the cell than inside.

  • Describe the relative concentration of K+ inside and outside the cell.

    K+ concentration is higher inside the cell than outside.

  • What drives Na+ movement across the membrane?

    Na+ moves into the cell driven by both its chemical gradient (high outside to low inside) and electrical gradient (negative inside).

  • What drives K+ movement across the membrane?

    K+ tends to move out of the cell down its chemical gradient but is pulled back in by the electrical gradient.

  • How is the resting membrane potential maintained?

    It is maintained mainly by the Na+/K+ pump and leak channels, keeping K+ high inside and Na+ high outside.

  • What is the typical value of resting membrane potential in neurons?

    The typical resting membrane potential of a neuron is about -70 mV.

  • Why is the resting membrane potential negative?

    Because more positive ions (K+) leak out than Na+ leak in, leaving the inside more negative.

  • What role do leak channels play in membrane potential?

    Leak channels allow K+ to move out, contributing to the negative resting membrane potential.

  • Explain the role of the Na+/K+ pump in membrane potential.

    The Na+/K+ pump moves 3 Na+ out and 2 K+ in, using ATP to maintain ion gradients and resting potential.

  • How does equilibrium potential relate to ion movement?

    At equilibrium potential, the electrical and chemical forces on an ion are balanced, so there is no net ion movement.

  • What happens if membrane potential equals Na+ equilibrium potential?

    There is no net movement of Na+ ions across the membrane at this voltage.