Neuron Ion Channels and Membrane Potential
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Neuron Ion Channels and Membrane Potential

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Questions and Answers

Which ion channels are responsible for the resting membrane potential?

  • Calcium channels
  • Sodium channels
  • Chloride channels
  • Potassium channels (correct)

    • Ion channels in the membrane are non-selective and allow all ions to pass through.

    False

    What are the two forces that act on an ion in the electrochemical gradient?

    Concentration gradient and voltage difference of the membrane

    The direction and size of ion movement depend on the _______________ and the voltage difference of the membrane.

    <p>concentration gradient</p> Signup and view all the answers

    Match the type of gated ion channel with its response:

    <p>Voltage-gated channels = Change in voltage across membrane Chemically-gated channels = Molecules that bind or alter channel protein Mechanically-gated channels = Force applied to membrane</p> Signup and view all the answers

    Graded membrane potentials are changes from the action potential.

    <p>False</p> Signup and view all the answers

    What is the purpose of the Nernst Equation?

    <p>To calculate the equilibrium membrane potential</p> Signup and view all the answers

    What happens to K+ ions as they diffuse out of the cell along the concentration gradient?

    <p>They leave behind negative charges within the cell.</p> Signup and view all the answers

    What type of synapse couples neurons electrically through gap junctions?

    <p>Electrical synapse</p> Signup and view all the answers

    Electrical synapses allow temporal summation.

    <p>False</p> Signup and view all the answers

    What is the primary function of connexons in electrical synapses?

    <p>To couple neurons electrically through gap junctions</p> Signup and view all the answers

    Neurotransmitters bind to ______ receptors, which can be either ionotropic or metabotropic.

    <p>specific</p> Signup and view all the answers

    Match the following neurotransmitter receptors with their characteristics:

    <p>Ionotropic = Fast and short-lived responses Metabotropic = Signalling cascade is initiated first</p> Signup and view all the answers

    What is the primary function of the postsynaptic cell in chemical synaptic transmission?

    <p>To sum the excitatory and inhibitory input</p> Signup and view all the answers

    All neurotransmitters bind to metabotropic receptors.

    <p>False</p> Signup and view all the answers

    What are the two main types of neurotransmitter receptors?

    <p>Ionotropic receptors and Metabotropic receptors</p> Signup and view all the answers

    What is the main function of the sodium-potassium pump in neurons?

    <p>To establish concentration gradients</p> Signup and view all the answers

    The resting potential of a neuron is a temporary change in membrane potential.

    <p>False</p> Signup and view all the answers

    What is the function of ion channels in generating and transmitting electrical signals in neurons?

    <p>Ion channels open and close to generate action potentials by allowing ions to move across the cell membrane, changing the membrane potential.</p> Signup and view all the answers

    The movement of electrically charged particles, ions, across cell membranes is caused by _________________.

    <p>voltage</p> Signup and view all the answers

    Which of the following is NOT a type of ion transporter?

    <p>Myelin</p> Signup and view all the answers

    Astrocytes are involved in the production of myelin in the CNS.

    <p>False</p> Signup and view all the answers

    Match the following structures with their functions:

    <p>Schwann cell = Produce myelin in the PNS Oligodendrocyte = Produce myelin in the CNS Astrocyte = Contribute to the blood-brain barrier Myelin = Insulate axons</p> Signup and view all the answers

    What is the main difference between resting potential and action potential?

    <p>Resting potential is the steady-state membrane potential of a resting neuron, while action potential is a rapid, large change in membrane potential.</p> Signup and view all the answers

    Study Notes

    Ion Channels and Membrane Potential

    • Ion channels in the membrane are selective and allow some ions to pass more easily.
    • The direction and size of ion movement depends on the concentration gradient and the voltage difference of the membrane.
    • Leak potassium channel is responsible for the resting membrane potential.
    • Potassium ions diffuse out of the cell along the concentration gradient and leave behind negative charges within the cell.
    • Potassium equilibrium potential is the membrane potential at which the net movement of K+ ceases.

    Types of Ion Channels

    • Some ion channels are “gated”: Open and close under certain conditions.
    • Voltage-gated channels respond to change in voltage across the membrane.
    • Chemically-gated channels depend on molecules that bind or alter channel protein.
    • Mechanically-gated channels respond to force applied to the membrane.

    Graded Changes and Ion Transport

    • Graded membrane potentials are changes from the resting potential.
    • Ion transporters and channels generate membrane potential.
    • Ion channels and ion transporters in the membrane create the membrane, resting and action potentials.

    Electrical Properties of Neurons

    • Membrane potential is a charge difference across the membrane, with the inside of the cell negative relative to the outside.
    • Resting potential is the steady state membrane potential of a resting neuron.
    • Action potential, or nerve impulse, is a rapid, large change in membrane potential.

    Sodium-Potassium Pump

    • Sodium-potassium pump—moves Na+ ions from inside, exchanges for K+ from outside.
    • Establishes concentration gradients.
    • The Na+-K+ pump is an antiporter, or sodium-potassium ATPase, as it requires ATP.

    Electrical Synapses

    • Electrical synapses couple neurons electrically through gap junctions.
    • Characteristics of electrical synapses include:
    • Fast transmission
    • No synaptic cleft
    • No synaptic vesicles
    • No possibility of IPSPs

    Chemical Synapses

    • Chemical synapses involve the release of neurotransmitters from the presynaptic neuron.
    • Characteristics of chemical synapses include:
    • Slower transmission
    • Presence of synaptic cleft
    • Presence of synaptic vesicles
    • Possibility of IPSPs

    Neuromuscular Junction

    • The neuromuscular junction is a chemical synapse between motor neurons and skeletal muscle cells.
    • ACh receptor is a ligand-gated, non-selective cationic channel.

    Postsynaptic Potentials

    • Postsynaptic cell sums the excitatory and inhibitory input.
    • EPSP – excitatory synapse
    • IPSP – inhibitory synapse

    Neurotransmitters and Receptors

    • Major neurotransmitters of the nervous system include:
    • Acetylcholine
    • Dopamine
    • Norepinephrine
    • Serotonin
    • Glutamate
    • GABA
    • Glycine
    • Ionotropic receptors are ion channels, whereas metabotropic receptors are not ion channels.
    • Examples of ionotropic receptors include glutamate receptors, GABAA, and glycine receptors.
    • Examples of metabotropic receptors include glutamate receptors and GABAB receptors.

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    Description

    This quiz covers the major ions in neurons, ion channels, and the measurement of membrane potential. It discusses the selective nature of ion channels and how ions move based on concentration gradient and voltage difference.

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