Neuroscience: Neuronal Membrane and Action Potentials
41 Questions
1 Views

Neuroscience: Neuronal Membrane and Action Potentials

Created by
@ExceptionalVenus2629

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What defines an action potential in neurons?

  • A constant electrical charge
  • A series of rapid voltage reversals (correct)
  • A continuous flow of electrons
  • A single voltage block

    • How does the electrical signal in neurons differ from that in wires?

  • Neurons conduct impulses via ion movement, not electron movement (correct)
  • Wires conduct electrical signals using neurotransmitters
  • Neuronal signals are slower and less reliable
  • Wires rely on ion exchanges across membranes

    • What term is used to describe the nature of action potentials?

  • Continuous signal
  • All or nothing (correct)
  • Analog signal
  • Variable signal

    • What role do dendrites play in neuronal communication?

    <p>They contain receptors for neurotransmitters</p> Signup and view all the answers

    What is the primary mode of signal transmission in neurons during an action potential?

    <p>Potential difference across membranes</p> Signup and view all the answers

    What is the primary reason for the negative resting potential in a neuron?

    <p>Higher concentration of negatively charged anions inside the neuron</p> Signup and view all the answers

    How does sodium (Na+) move across the neuronal membrane?

    <p>Through the action of a sodium-potassium pump</p> Signup and view all the answers

    What happens during the action potential in neurons?

    <p>There is a series of rapid voltage reversals due to ion exchange</p> Signup and view all the answers

    What is the result of the sodium-potassium pump's activity?

    <p>An increase in Na+ concentration outside the neuron</p> Signup and view all the answers

    Which ions are involved in establishing the resting membrane potential?

    <p>Potassium and negatively charged anions</p> Signup and view all the answers

    What is the role of dendrites in neuronal communication?

    <p>To receive chemical messengers</p> Signup and view all the answers

    What ion concentration is higher outside the neuron compared to inside?

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

    What initiates the propagation of an action potential down the axon?

    <p>An influx of positively charged ions</p> Signup and view all the answers

    Which amino acid is a precursor for the synthesis of dopamine?

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

    Which of the following dopamine receptors is considered excitatory?

    <p>D5</p> Signup and view all the answers

    How is serotonin deactivated in the nervous system?

    <p>Re-uptake via a transporter</p> Signup and view all the answers

    What is a common characteristic of noradrenaline receptors?

    <p>They are all G-Coupled metabotropic receptors</p> Signup and view all the answers

    Which neurotransmitter is synthesized from dopamine?

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

    Which enzyme is involved in the breakdown of dopamine?

    <p>Both B and C</p> Signup and view all the answers

    What type of receptors do serotonin molecules primarily interact with?

    <p>G-Coupled metabotropic receptors and one ionotropic receptor</p> Signup and view all the answers

    Which of the following is NOT a function of dopamine receptor subtypes?

    <p>Muscle contraction</p> Signup and view all the answers

    What behavioral disorder can be treated with L-Dopa?

    <p>Parkinson's disease</p> Signup and view all the answers

    How does the body primarily excrete excess dopamine?

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

    What is the primary function of the axon terminals in a neuron?

    <p>To release neurotransmitters into the synapse</p> Signup and view all the answers

    Which of the following correctly defines a graded potential?

    <p>A localized change in membrane potential that decreases with distance</p> Signup and view all the answers

    What is the significance of the resting potential in neurons?

    <p>It is essential for action potentials to be generated</p> Signup and view all the answers

    Which neurotransmitter is primarily involved in the modulation of mood and emotion?

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

    What does saltatory conduction refer to in neuronal communication?

    <p>The jumping of action potentials between nodes of Ranvier</p> Signup and view all the answers

    What distinguishes the two classes of receptors associated with neurotransmitters?

    <p>Whether they are ionotropic or metabotropic</p> Signup and view all the answers

    Which mechanism is NOT commonly involved in the deactivation of neurotransmitters?

    <p>Direct absorption by postsynaptic neurons</p> Signup and view all the answers

    Where are most neurotransmitters synthesized within a neuron?

    <p>Soma (cell body)</p> Signup and view all the answers

    What role do calcium ions play in neurotransmitter release?

    <p>They enter the neuron and form a calcium calmodulin complex.</p> Signup and view all the answers

    What is the primary mechanism by which neurotransmitters are released into the synaptic cleft?

    <p>Exocytosis.</p> Signup and view all the answers

    Which type of receptors open or close ion channels directly upon neurotransmitter binding?

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

    What happens when a neurotransmitter binds to a metabotropic receptor?

    <p>It activates a G-protein, which then sends second messengers.</p> Signup and view all the answers

    What is one of the mechanisms by which neurotransmitters are deactivated?

    <p>Being broken down by enzymes.</p> Signup and view all the answers

    Which option describes how reuptake works in the context of neurotransmission?

    <p>Neurotransmitters are actively moved back into the pre-synaptic neuron.</p> Signup and view all the answers

    What happens when neurotransmitters diffuse across the synaptic cleft?

    <p>They bind to receptors on the post-synaptic membrane.</p> Signup and view all the answers

    What is the function of calmodulin in neurotransmitter release?

    <p>To form a complex with calcium ions that facilitates vesicle binding.</p> Signup and view all the answers

    What is a key characteristic of ionotropic receptors compared to metabotropic receptors?

    <p>They directly alter ion channel activity upon binding.</p> Signup and view all the answers

    Which neurotransmitter example is synthesized in the axon terminal from components typically found in food?

    <p>Acetylcholine.</p> Signup and view all the answers

    Study Notes

    Neuronal Membrane

    • Negatively charged anions (A-) are produced inside the neuron and cannot leave
    • Sodium ions (Na+) are positively charged and do not move freely across the membrane
    • Sodium-potassium pump actively pumps 3 Na+ out for every 2 K+ brought inside the neuronal membrane
    • This exchange of ions ensures a negative resting potential

    Resting Membrane Potential

    • Higher concentration of positively charged ions outside the membrane
    • Higher concentration of negatively charged ions inside the membrane

    Neuronal Communication

    • Neurons communicate through electrochemical signals
    • Chemical messengers (neurotransmitters) are received by the dendrites
    • An electrical event, known as an action potential, propagates down the axon
    • This triggers the release of neurotransmitters from the presynaptic terminal

    Action Potentials

    • Occur due to a rapid exchange of ions across the neuronal membrane
    • Characterized by a series of voltage reversals along the axon
    • "All or nothing" response, meaning they either occur or do not occur

    Action Potential vs. Electrical Signal in Wires

    • Electrical wires conduct a flow of electrons
    • Neurons conduct impulses that are electrical in nature
    • Neuron signals, known as action potentials, involve ion movement, not electron movement

    Action Potential Stages

    • Stage 1: Dendrites receive neurotransmitters
      • Receptors in dendrites bind to neurotransmitters
    • Stage 2: Neurotransmitter Release
      • Action potential reaches the axon terminal, opening calcium channels
      • Calcium ions bind to calmodulin, forming a calcium-calmodulin complex
      • Calcium-calmodulin complex binds to synaptic vesicles, facilitating release of neurotransmitters through exocytosis
    • Stage 3: Receptor Activation
      • Neurotransmitters diffuse across the synaptic cleft and bind to receptors on the postsynaptic membrane
      • Receptor activation can be excitatory or inhibitory, causing changes in the postsynaptic membrane potential
      • Two types of receptors:
        • Ionotropic receptors: Ligand-gated ion channels that directly open or close ion channels upon neurotransmitter binding
        • Metabotropic receptors: G-coupled receptors that activate G-proteins, which can interact with ion channels or create intracellular messengers
    • Stage 4: Deactivation of Neurotransmitters
      • Neurotransmitters are deactivated through several mechanisms:
        • Diffusion: Moving away from the synaptic cleft
        • Degradation: Enzymes break down the neurotransmitter
        • Reuptake: Neurotransmitter is taken back into the presynaptic neuron
        • Removal: Glial cells bind and remove the neurotransmitter

    Neurotransmitter Synthesis and Deactivation

    Acetylcholine

    • Synthesized in the axon terminal from acetyl coenzyme A and choline
    • Deactivated by the enzyme acetylcholinesterase

    Dopamine

    • Synthesized from L-Dopa, which comes from tyrosine
    • Deactivated by enzymes, with breakdown products excreted in urine
    • Some excess dopamine is re-uptaken into the presynaptic neuron

    Serotonin

    • Synthesized in the nerve terminal from tryptophan
    • Deactivated via reuptake by a serotonin transporter pump in the presynaptic neuron

    Noradrenaline

    • Synthesized from dopamine in the axon terminal
    • Deactivated via reuptake by a noradrenergic transporter

    Neurotransmitter Receptors

    Dopamine

    • Interacts with g-coupled metabotropic receptors
    • Five subtypes (D1-D5)
    • D1 and D5 are excitatory
    • D2, D3, and D4 are inhibitory

    Serotonin

    • Interacts with a family of at least 7 receptors (5-HT receptors)
    • Most are G-coupled metabotropic receptors
    • One is an ionotropic receptor
    • Some are excitatory, some are inhibitory

    Noradrenaline

    • Interacts with at least 3 G-coupled metabotropic receptors (alpha1, alpha2, and beta receptors)
    • Each has multiple subtypes
    • Some are excitatory, some are inhibitory

    Key Concepts to Know

    • Understand neuron structure and function
    • Identify parts of the neuron responsible for communication and neurotransmission
    • Define key terms related to cellular communication
    • Describe the resting membrane potential and ion concentrations
    • Explain graded potentials and their generation
    • Outline the stages of action potential generation and function
    • Explain saltatory conduction
    • Identify components of the synapse
    • Define neurotransmitters and their differences from hormones
    • Explain the effects of neurotransmitters on postsynaptic membrane
    • Identify neurotransmitter synthesis, storage, and release mechanisms
    • Explain the role of action potential in neurotransmitter release
    • Distinguish between ionotropic and metabotropic receptors
    • Describe the main methods of neurotransmitter deactivation
    • Identify the brain regions for key neurotransmitter production (acetylcholine, dopamine, serotonin, noradrenaline)

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Cellular Communication & Neurotransmission (Biopsychology) PDF

    Description

    This quiz explores the dynamics of the neuronal membrane, including resting membrane potential and the role of ion exchange. It covers how neurons communicate through electrochemical signals and the characteristics of action potentials. Test your understanding of these fundamental neuroscience concepts.

    More Like This

    Neuronal Action Potential Characteristics Quiz
    10 questions

    Neuronal Action Potential Characteristics Quiz

    WellIntentionedSocialRealism avatar
    WellIntentionedSocialRealism
    Neuroscience: Cell Membrane Channels
    44 questions

    Neuroscience: Cell Membrane Channels

    WellKnownConstellation avatar
    WellKnownConstellation
    Neuroscience: Action Potentials and Membrane Dynamics
    10 questions

    Neuroscience: Action Potentials and Membrane Dynamics

    IllustriousRocket avatar
    IllustriousRocket
    Biologie Neuronale - Potentiel d'Action
    37 questions

    Biologie Neuronale - Potentiel d'Action

    DarlingDrama avatar
    DarlingDrama
    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser