Autonomic and Somatic Motor Control
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Questions and Answers

What triggers the exocytosis of synaptic vesicles?

  • Na+ entry
  • Ca2+ entry (correct)
  • K+ entry
  • Cl- entry
  • What type of receptors do adrenergic receptors belong to?

  • Ligand-gated receptors
  • Ion channel receptors
  • Voltage-gated receptors
  • G-protein coupled receptors (correct)
  • What does the binding of norepinephrine (NE) to its receptor lead to?

  • Exocytosis of synaptic vesicles (correct)
  • Dissociation of G-proteins
  • Immediate response termination
  • Entry of Cl- ions
  • How does an increase in neurotransmitter concentration affect the response?

    <p>Allows for a longer or stronger response</p> Signup and view all the answers

    Which ion is specifically involved in the opening of voltage-gated channels during neurotransmitter release?

    <p>Ca2+</p> Signup and view all the answers

    What is a notable characteristic of the response mediated by adrenergic receptors?

    <p>Slow onset and prolonged duration</p> Signup and view all the answers

    What type of control is primarily observed at the SA node in contrast to the ventricles and blood vessels?

    <p>Antagonistic control</p> Signup and view all the answers

    Which neurotransmitter is primarily used in sympathetic pathways?

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

    What percentage of all parasympathetic fibers does the vagus nerve contain?

    <p>75%</p> Signup and view all the answers

    What is the primary function of the vagus nerve in the autonomic nervous system?

    <p>Sending sensory information from organs to the brain</p> Signup and view all the answers

    What role do sympathetic ganglia play in the autonomic nervous system?

    <p>They facilitate the function of sympathetic pathways</p> Signup and view all the answers

    What type of control do veins and arterioles primarily exhibit?

    <p>Sympathetic control only</p> Signup and view all the answers

    Which statement accurately describes the neurotransmitters used in parasympathetic pathways?

    <p>They utilize acetylcholine exclusively</p> Signup and view all the answers

    Why is antagonistic control not seen in ventricles, veins, and arterioles?

    <p>These areas only require single-type control</p> Signup and view all the answers

    In the context of sympathetic and parasympathetic pathways, what is a significant difference in neurotransmitter usage?

    <p>Sympathetic pathways use norepinephrine while parasympathetic pathways use acetylcholine</p> Signup and view all the answers

    What triggers the exocytosis of synaptic vesicles at a sympathetic neuroeffector junction?

    <p>Influx of calcium ions</p> Signup and view all the answers

    What happens to norepinephrine after it activates the adrenergic receptor?

    <p>It diffuses away from the synapse</p> Signup and view all the answers

    What role do voltage-gated Ca2+ channels play in the sympathetic neuroeffector junction?

    <p>They allow calcium ions to enter the axon varicosity</p> Signup and view all the answers

    What is one possible fate of norepinephrine following its release into the synaptic cleft?

    <p>It may be reabsorbed into synaptic vesicles</p> Signup and view all the answers

    What initiates the process of norepinephrine release at the sympathetic neuroeffector junction?

    <p>Depolarization of the varicosity membrane</p> Signup and view all the answers

    What is the primary type of receptor that norepinephrine binds to in postganglionic sympathetic target cells?

    <p>Adrenergic receptors</p> Signup and view all the answers

    What substance is responsible for the removal of norepinephrine from the synapse?

    <p>Monoamine oxidase (MAO)</p> Signup and view all the answers

    Which event directly leads to calcium ion entry in the axon varicosity during norepinephrine release?

    <p>Opening of voltage-gated calcium channels</p> Signup and view all the answers

    What is the role of norepinephrine (NE) in the sympathetic nervous system?

    <p>Acts as a neurotransmitter to stimulate target cells</p> Signup and view all the answers

    What occurs after norepinephrine has diffused away from the synapse?

    <p>Receptor activation ceases</p> Signup and view all the answers

    What distinguishes selective beta-blockers from non-selective beta-blockers?

    <p>Selective beta-blockers mostly affect the heart.</p> Signup and view all the answers

    Which neurotransmitter is associated primarily with the parasympathetic pathway?

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

    Which receptor subtype is NOT primarily associated with the sympathetic pathway?

    <p>Muscarinic receptor</p> Signup and view all the answers

    What is the result of sympathetic pathway activation?

    <p>Increased blood flow to muscles</p> Signup and view all the answers

    How do beta-blockers primarily function in the body?

    <p>They block the action of norepinephrine.</p> Signup and view all the answers

    Which type of pathway does the adrenal medulla primarily belong to?

    <p>Sympathetic pathway</p> Signup and view all the answers

    What type of receptor is primarily found on the target cells of the sympathetic pathway?

    <p>Adrenergic receptor</p> Signup and view all the answers

    Which neurotransmitter is NOT typically used in the somatic motor pathway?

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

    Which receptor subtype is associated with the effects of epinephrine in the body?

    <p>Beta 1 receptor</p> Signup and view all the answers

    What effect do non-selective beta-blockers have on the body?

    <p>They affect multiple systems, including the respiratory system.</p> Signup and view all the answers

    What triggers the opening of voltage-gated Ca2+ channels at the sympathetic neuroeffector junction?

    <p>Action potential arrival</p> Signup and view all the answers

    Which enzyme is responsible for the metabolism of norepinephrine?

    <p>Monoamine oxidase</p> Signup and view all the answers

    What is the role of tyrosine in the sympathetic neuroeffector junction?

    <p>Precursor for norepinephrine synthesis</p> Signup and view all the answers

    What happens when an action potential arrives at the varicosity?

    <p>Voltage-gated Ca2+ channels open</p> Signup and view all the answers

    What is the primary action of norepinephrine at the target cell?

    <p>Stimulation of smooth muscle contraction</p> Signup and view all the answers

    What is the role of the varicosity in the autonomic synapse?

    <p>Release site for norepinephrine</p> Signup and view all the answers

    Which ion's influx is crucial for norepinephrine release?

    <p>Ca2+</p> Signup and view all the answers

    Which of the following correctly describes the process of norepinephrine removal?

    <p>Reuptake by the varicosity</p> Signup and view all the answers

    What occurs to neurotransmitter molecules after they are released into the synaptic cleft?

    <p>They bind to receptors on target cells</p> Signup and view all the answers

    What initiates the entire process of norepinephrine release at the sympathetic neuroeffector junction?

    <p>Action potential</p> Signup and view all the answers

    Study Notes

    Autonomic and Somatic Motor Control

    • Antagonistic control is predominantly observed at the sinoatrial (SA) node, not in ventricles, veins, or arterioles.
    • Sympathetic ganglia are organized in two chains flanking the vertebral column.
    • The vagus nerve contains approximately 75% of all parasympathetic fibers, transmitting sensory data from internal organs to the brain and sending output from the brain to organs.

    Neurotransmitters and Receptors

    • Sympathetic pathways utilize norepinephrine (NE) or acetylcholine (ACh).
    • Parasympathetic pathways primarily use acetylcholine (ACh).
    • Selective beta-blockers influence heart function, while non-selective beta-blockers affect various body areas.

    Autonomic Pathways Overview

    • Parasympathetic Pathway:

      • Originates from the CNS, synapses at a ganglion.
      • Utilizes nicotinic and muscarinic receptors targeting smooth and cardiac muscle, some endocrine and exocrine glands, and adipose tissue.
    • Sympathetic Pathway:

      • Initiates in the CNS and releases norepinephrine.
      • Targets through α and β adrenergic receptors affecting a wide array of bodily functions.

    Comparing Efferent Nervous System Divisions

    • A greater number of neurons are present in autonomic pathways compared to somatic motor pathways.
    • Somatic motor pathways target muscles directly, while autonomic pathways release neurotransmitters affecting various tissues.

    Adrenergic Receptors and Neurotransmitter Function

    • Norepinephrine (NE) release at sympathetic neuroeffector junctions occurs through action potentials triggering calcium ion (Ca2+) influx, leading to neurotransmitter exocytosis.
    • Binding of NE to adrenergic receptors activates a slower, more prolonged response due to G-protein coupling.
    • NE can diffuse away from the synapse, be taken back into synaptic vesicles, or be metabolized by monoamine oxidase (MAO).

    Summary of Receptor Dynamics

    • All adrenergic receptors are G-protein coupled, resulting in slower onset and offset of physiological responses.
    • Increased neurotransmitter concentration can lead to a more robust response in target tissues.

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    Physiology Chp 11 Part B PDF

    Description

    This quiz delves into the intricacies of autonomic and somatic motor control, exploring key concepts such as antagonistic control, neurotransmitters, and the sympathetic and parasympathetic pathways. Test your knowledge on the roles of various receptors and the impact of selective beta-blockers in heart function. Perfect for those studying neuroanatomy and physiology.

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