L24. Neuroscience - Electrochemical Basis of Neural Signaling
38 Questions
2 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What primarily determines the neuronal membrane potential?

  • The function of the Na+/K+ pump and leak channels (correct)
  • The concentration of neurotransmitters in the synapse
  • The polarization of the axonal terminals
  • The activity of calcium channels during action potentials

    • Which mechanism is responsible for the gating of ion channels in neuronal signaling?

  • Voltage changes in the extracellular fluid
  • Ligand binding at the synaptic cleft
  • Mechanical pressure from adjacent cells
  • Various signaling molecules affecting channel opening (correct)

    • How does the propagation of graded potentials primarily occur in neurons?

  • By continuous action potential firing
  • Through fast sodium ion influx only
  • Via passive spread and local depolarization (correct)
  • Through the activation of voltage-gated potassium channels

    • What role does the axon myelination play in action potential propagation?

    <p>Facilitates faster propagation by insulating the axon</p> Signup and view all the answers

    Which of the following statements about action potentials is accurate?

    <p>Ion channel inactivation significantly contributes to the shape and duration of action potentials</p> Signup and view all the answers

    What defines the voltage difference known as the membrane potential?

    <p>The difference in charge between the cytoplasmic and extracellular sides</p> Signup and view all the answers

    Which feature characterizes electrical synaptic transmission compared to chemical synaptic transmission?

    <p>It occurs through gap junctions allowing direct cell coupling</p> Signup and view all the answers

    What is one of the primary determinants of action potential propagation velocity?

    <p>The diameter of the axon and its myelination</p> Signup and view all the answers

    How do excitatory synapses differ from inhibitory synapses?

    <p>Excitatory synapses facilitate depolarization in the postsynaptic cell</p> Signup and view all the answers

    Which ion current is primarily responsible for defining the membrane potential?

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

    What is the primary purpose of the Goldman equation in relation to membrane potential?

    <p>To compute the membrane potential considering all ionic currents</p> Signup and view all the answers

    How do graded potentials behave as they propagate through the neuron's dendrites?

    <p>They decay exponentially and can become distorted</p> Signup and view all the answers

    Which ion current is considered to reduce the membrane potential?

    <p>Na+ current</p> Signup and view all the answers

    What condition must be met for an action potential to occur following a graded potential?

    <p>The graded potential must reach a certain threshold</p> Signup and view all the answers

    In the context of neuronal signaling, how do graded potentials integrate in the soma?

    <p>They add up and contribute to reaching the threshold</p> Signup and view all the answers

    Which component is typically eliminated in the Goldman equation due to its negligible contribution?

    <p>Cl- current</p> Signup and view all the answers

    What is the shape of the decay pattern of graded potentials as they propagate?

    <p>Exponential decay</p> Signup and view all the answers

    What is primarily described by the cable properties of the membrane?

    <p>Passive propagation of graded potentials</p> Signup and view all the answers

    In terms of membrane potential, what is the role of the K+ current?

    <p>It stabilizes the membrane potential around the resting state</p> Signup and view all the answers

    What role does the inactivation of voltage-gated Na+ channels play in action potentials?

    <p>It facilitates unidirectional propagation and establishes the refractory period.</p> Signup and view all the answers

    Which factor is NOT a determinant of conduction velocity in neurons?

    <p>Voltage-gated K+ channel density</p> Signup and view all the answers

    What effect does the myelination of axons have on action potentials?

    <p>It accelerates the propagation of action potentials.</p> Signup and view all the answers

    What is the main difference between electrical and chemical synapses?

    <p>Chemical synapses typically utilize neurotransmitters while electrical synapses transmit current directly.</p> Signup and view all the answers

    What can happen during a prolonged depolarizing signal in a neuron?

    <p>Repetitive action potentials may occur, depending on firing patterns.</p> Signup and view all the answers

    Which of the following statements about voltage-gated K+ channels is correct?

    <p>Their activity helps define the properties of action potentials.</p> Signup and view all the answers

    What occurs at chemical synapses when an action potential triggers the opening of voltage-gated Ca2+ channels?

    <p>Calcium influx results in fusion of synaptic vesicles and neurotransmitter release.</p> Signup and view all the answers

    Which disease is associated with deficiencies in myelination?

    <p>CMT (Charcot-Marie-Tooth disease)</p> Signup and view all the answers

    What is the primary function of the nodes of Ranvier in myelinated axons?

    <p>They allow passive propagation and retriggering of action potentials.</p> Signup and view all the answers

    What role does the protein Synaptotagmin serve in the release of neurotransmitters?

    <p>It acts as a Ca2+ sensor.</p> Signup and view all the answers

    Which of the following best describes the nature of synaptic transmission?

    <p>It is probabilistic and can vary between trials.</p> Signup and view all the answers

    What defines presynaptic active zones in the context of synaptic transmission?

    <p>They are morphological specializations with electron dense material and synaptic vesicles.</p> Signup and view all the answers

    What is the primary function of excitatory synapses in neuronal networks?

    <p>To evoke depolarization in postsynaptic neurons.</p> Signup and view all the answers

    What distinguishes neuropeptide transmitters from traditional neurotransmitters?

    <p>They are packed in large dense-core vesicles.</p> Signup and view all the answers

    In the context of synaptic connections, what does the term 'convergence' refer to?

    <p>The merging of signals from various neurons onto a single neuron.</p> Signup and view all the answers

    What type of synapses do inhibitory signals typically form?

    <p>Axosomatic synapses</p> Signup and view all the answers

    How do deficiencies in the proteins associated with neurotransmitter release affect neurological health?

    <p>They may result in severe neurological and mental disorders.</p> Signup and view all the answers

    What structural feature is critical in the fusion of synaptic vesicles with the plasma membrane?

    <p>The coil-coiled four-helical SNARE protein complex.</p> Signup and view all the answers

    What role do clusters of Ca2+ channels play in presynaptic active zones?

    <p>They facilitate the release of neurotransmitters upon depolarization.</p> Signup and view all the answers

    Study Notes

    Learning Objectives

    • Students will demonstrate effective understanding of neuron functions
    • Explain how neurons send and receive information
    • Analyze the mechanisms driving neuronal membrane potential
    • Explain the role of graded potentials in neuronal signaling
    • Explain how ion channels lead to action potentials
    • Analyze determinants of action potential and how manipulation works
    • Explain how ion channel inactivation impacts action potentials
    • Explain action potential propagation and its related pathologies
    • Compare electrical and chemical synaptic transmissions
    • Summarize chemical synaptic transmission steps
    • Explain the function of the presynaptic active zone
    • Explain the probabilistic nature of synaptic transmission
    • Compare excitatory and inhibitory synapses
    • Explain neuronal network formation and give examples

    Outline

    • Neuronal structure and information transfer
    • Membrane potential
    • Graded potential
    • Action potential
    • Synapses
    • Neuronal networks

    Neuronal Structure and Information Transfer

    • Neurons are the fundamental signaling units
    • Dendrites receive input (passive electrical propagation)
    • Soma processes input
    • Axon transmits signal (active electrical propagation)
    • Axon terminals transmit signals to other neurons or cells

    Membrane Potential

    • Membrane potential is the voltage difference across the membrane
    • It arises due to ion channels and the sodium-potassium pump
    • Leak channels contribute significantly to the membrane potential
    • The Nernst equation can describe equilibrium potential for a specific ion
    • The Goldman equation is a more accurate description of membrane potential, considering multiple ions

    Graded Potentials

    • Graded potentials vary in size and shape depending on the stimulus
    • They are passively propagated along the neuron's dendrites and soma
    • They are important for integrating input signals
    • They can be summated and decay over distance

    Action Potential

    • Action potentials are rapid, large changes in membrane potential
    • Triggered by depolarization to threshold
    • Characterized by rapid depolarization (Na+ influx), repolarization (K+ efflux), and hyperpolarization
    • Voltage-gated ion channels (Na+ and K+) are crucial in action potential generation
    • Action potential propagation is unidirectional and has a refractory period
    • Propagation is influenced by myelination and axon diameter

    Synapses

    • Synapses are specialized junctions between neurons (or neurons and other cells)
    • Chemical synapses are the most common type
    • Action potential triggers neurotransmitter release
    • Neurotransmitters bind to receptors, leading to postsynaptic potential changes
    • Electrical synapses transmit signals directly via gap junctions

    Neuronal Networks

    • Networks formed by connections among neurons
    • Examples might include the knee-jerk reflex or more complex neural pathways
    • Networks are characterized by convergence, divergence, and feedback loops

    Action Potential: Study Questions

    • Describing the effects of extracellular K+ increase on the membrane potential
    • Explaining how extracellular Na+ increase affects membrane potential
    • Exploring the role of increased Na+ permeability on membrane potential
    • Determining the impact of blocking Na+ channels on membrane potential

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    HBF-III LEC 24 Neuroscience Electrochemical Basis Neural Signaling Notes PDF 2025

    Description

    This quiz covers key concepts related to neuron functions, including how neurons send and receive information, the mechanisms of membrane potential, and the role of synapses. Students will explore action potentials, graded potentials, and the differences between excitatory and inhibitory synapses. Gain a deeper understanding of neuronal networks and their significance in signaling.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser