Neuron Communication Quiz

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Questions and Answers

What is the primary function of dendrites in a neuron?

  • To process and integrate information
  • To receive incoming signals (correct)
  • To transmit information to neighboring neurons
  • To carry information over long distances

What occurs when a neuron reaches the threshold of -55 millivolts?

  • The neuron ceases all activity
  • The neuron achieves resting potential
  • The neuron starts releasing neurotransmitters
  • The neuron transmits an action potential (correct)

What is the resting potential of a typical neuron?

  • -70 millivolts (correct)
  • +10 millivolts
  • -100 millivolts
  • 0 millivolts

How is information coded within the nervous system?

<p>Using action potentials of fixed size and shape (D)</p> Signup and view all the answers

What is the main reason for the chemical nature of synaptic transmission?

<p>To facilitate the movement of neurotransmitters between neurons (B)</p> Signup and view all the answers

What do excitatory signals mainly influence in a neuron?

<p>The generation of action potentials (C)</p> Signup and view all the answers

What role do ions play in the generation of action potentials?

<p>They generate electrical signals by moving across the membrane (D)</p> Signup and view all the answers

What is an action potential characterized by?

<p>A rapid change in membrane potential that propagates along the axon (A)</p> Signup and view all the answers

What is the primary voltage of a neuron at rest?

<p>-70 mV (C)</p> Signup and view all the answers

Which ion is more concentrated outside of the neuron at rest?

<p>Sodium (Na+) (B)</p> Signup and view all the answers

Which mechanism helps to maintain the resting membrane potential of -70 mV despite ion movement?

<p>A combination of diffusion, electrostatic pressure, and transporters (B)</p> Signup and view all the answers

What does the sodium-potassium pump do?

<p>Pumps potassium ions into the cell and sodium out (C)</p> Signup and view all the answers

What role does electrostatic pressure play in ion movement across the cell membrane?

<p>It prevents negative ions from entering the cell (B)</p> Signup and view all the answers

How does diffusion contribute to ion movement in the neuron?

<p>It moves ions from high to low concentration without energy (C)</p> Signup and view all the answers

What happens to potassium ions (K+) at the resting membrane potential?

<p>They are unable to leave the cell due to electrostatic pressure (D)</p> Signup and view all the answers

What energy source is used by the sodium-potassium pump to operate?

<p>ATP (C)</p> Signup and view all the answers

Flashcards

Action Potential

A signal a neuron transmits along its axon when enough stimulation occurs; the signal must be fast for an immediate reaction.

Neuron Anatomy

Structure of a neuron: dendrites (receive signals), cell body (processes information), axon (carries signals), and axon terminals (send signals to other cells).

Resting Potential

The electrical potential of a neuron when it's not transmitting a signal, approximately -70 millivolts.

Threshold of activation

The minimum level of stimulation needed to trigger an action potential (-55mV).

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Membrane Potential

The difference in electrical charge between the inside and outside of a cell.

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Synaptic communication

The chemical communication between two neurons.

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Electrical signal

Movement of ions (charged atoms) within a neuron.

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Information Coding

Brain information is represented by the frequency of action potentials.

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Resting Membrane Potential

The voltage difference across a neuron's membrane when it is not transmitting a signal. Typically around -70mV.

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Sodium (Na+)

A positively charged ion. More concentrated outside the neuron.

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Potassium (K+)

A positively charged ion. More concentrated inside the neuron.

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Chloride (Cl-)

A negatively charged ion. More concentrated outside the neuron.

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Diffusion

The movement of molecules from an area of high concentration to an area of low concentration, requiring no energy.

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Electrostatic Pressure

The force exerted by opposite charges attracting and like charges repelling; affects ion movements.

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Sodium-Potassium Pump

A protein that actively transports sodium out of and potassium into the neuron, maintaining the membrane potential.

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Active Transport

Transport of molecules across a membrane from low to high concentration, requiring energy.

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Study Notes

Neuron Communication

  • Neuron Anatomy:

    • Dendrites: Receive incoming signals.
    • Cell Body: Processes and integrates information.
    • Axon: Carries information over long distances.
    • Axon Terminal: Transmits information to the next cell.
  • Action Potential:

    • A neuron transmits a signal along the axon if incoming stimulation is strong enough.
    • The neuron "fires."
    • Electrical signals are fast for immediate reactions.
    • Inside of a neuron is more negative than outside.
    • Information in the brain is coded through action potentials (electrical impulses).
    • Action potentials are all the same size and shape.
    • Differences are in the firing frequency (higher or lower).
    • Action potentials regenerate at each node.
  • Synaptic Communication:

    • Synapses are chemical, not electrical.
    • Communication occurs between two neurons.
    • Threshold of activation is -55mV for an action potential.
    • Action potentials carry information through impulses.
    • Outside the neuron has no electricity. No AP outside.
  • Electrical Signals & Ions:

    • Electrical signals inside neurons are called action potentials.
    • Start in dendrites, end at terminals.
    • Signals are from ion flow (atoms with charges).
    • Ions are atoms or groups carrying a charge (positive or negative) from gaining/losing electrons.
    • Inside of neuron is more positively charged than outside.

Membrane Potential

  • Membrane Potential: Difference in charge between inside and outside the cell.
  • Resting Potential: Approximately -70 mV (neuron is "at rest").
  • Electrochemical Gradient: A combination of chemical (concentration) and electrical (charge) gradients.

Electrical Excitability

  • Resting Membrane Potential: The neuron's potential when not transmitting information (maintains a state for rapid response to stimuli).
  • Action potential depends on resting membrane potential - maintains -70 mV for quick actions potentials.
  • Electrical excitability is due to the neuron's ability to maintain a potential that facilitates fast action potentials. The brain uses 20% of body energy.
  • Resting membrane potential is -70 mV.

Maintaining Resting Potential

  • 3 Mechanisms (continuous ion movement):
    • Diffusion: Natural movement from high to low concentration. Sodium and Potassium move oppositely, based on concentration differences. Chloride moves towards negative charges if possible. Requires no energy (passive).
    • Electrostatic Pressure: Positive charges are pushed away from positive charges; negative charges attract negative charges. Attracts/repel charges based on the relative polarity. Requires no energy (passive).
    • Transporters: Active transport that uses ATP (energy) to move substances AGAINST their concentration gradient. This ensures the neuron remains at its negative resting potential. Specifically, the sodium-potassium pump maintains the gradient by moving sodium out and potassium into the cell.

Ion Concentrations

  • Sodium (Na+):

    • More sodium outside of the neuron than inside
    • Positive charge
  • Potassium (K+):

    • More potassium inside of the neuron than outside
    • Positive charge
  • Chloride (Cl-):

    • More chloride outside of the neuron than inside
    • Negative charge
  • Polarized State:

    • Inside of a cell is negative, outside is positive.
    • Cell membrane is permeable to positive ions more than others due to negative interior. Neuron maintains -70 mv resting potential

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