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Questions and Answers
What is the primary function of dendrites in a neuron?
What is the primary function of dendrites in a neuron?
What occurs when a neuron reaches the threshold of -55 millivolts?
What occurs when a neuron reaches the threshold of -55 millivolts?
What is the resting potential of a typical neuron?
What is the resting potential of a typical neuron?
How is information coded within the nervous system?
How is information coded within the nervous system?
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What is the main reason for the chemical nature of synaptic transmission?
What is the main reason for the chemical nature of synaptic transmission?
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What do excitatory signals mainly influence in a neuron?
What do excitatory signals mainly influence in a neuron?
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What role do ions play in the generation of action potentials?
What role do ions play in the generation of action potentials?
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What is an action potential characterized by?
What is an action potential characterized by?
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What is the primary voltage of a neuron at rest?
What is the primary voltage of a neuron at rest?
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Which ion is more concentrated outside of the neuron at rest?
Which ion is more concentrated outside of the neuron at rest?
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Which mechanism helps to maintain the resting membrane potential of -70 mV despite ion movement?
Which mechanism helps to maintain the resting membrane potential of -70 mV despite ion movement?
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What does the sodium-potassium pump do?
What does the sodium-potassium pump do?
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What role does electrostatic pressure play in ion movement across the cell membrane?
What role does electrostatic pressure play in ion movement across the cell membrane?
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How does diffusion contribute to ion movement in the neuron?
How does diffusion contribute to ion movement in the neuron?
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What happens to potassium ions (K+) at the resting membrane potential?
What happens to potassium ions (K+) at the resting membrane potential?
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What energy source is used by the sodium-potassium pump to operate?
What energy source is used by the sodium-potassium pump to operate?
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Study Notes
Neuron Communication
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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.
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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.
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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.
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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
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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
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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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Description
Test your knowledge on neuron anatomy, action potentials, and synaptic communication. Understand the processes that allow neurons to transmit signals and how information is coded in the brain. This quiz covers essential concepts necessary for grasping how neurons interact and communicate effectively.