Pharmacology Lecture 3: Autonomic Nervous System
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Questions and Answers

What is the primary role of the parasympathetic division of the autonomic nervous system?

  • To engage in fight or flight responses
  • To increase heart rate during stress
  • To support 'rest and digest' functions (correct)
  • To balance sympathetic reflex responses

    • What is the primary function of baroreceptors in relation to blood pressure?

  • To inhibit sympathetic responses
  • To detect blood volume changes
  • To increase parasympathetic output
  • To send fewer impulses during low pressure (correct)

    • How does the autonomic nervous system respond to a fall in blood pressure?

  • By decreasing parasympathetic output and increasing sympathetic output (correct)
  • By decreasing sympathetic output and increasing blood flow
  • By increasing both sympathetic and parasympathetic outputs
  • By increasing parasympathetic outputs exclusively

    • Which system primarily controls dynamic antagonism in organ function?

    <p>A dominant nervous system</p> Signup and view all the answers

    What can modify the activities of the autonomic nervous system?

    <p>Strong emotional stimuli</p> Signup and view all the answers

    Which organs receive only sympathetic innervation?

    <p>Adrenal medulla and kidneys</p> Signup and view all the answers

    What main function is associated with the sympathetic system?

    <p>Controlling blood pressure</p> Signup and view all the answers

    Which of the following statements about dual innervation is true?

    <p>Both the sympathetic and parasympathetic divisions influence organ function</p> Signup and view all the answers

    Which type of signaling involves hormones released into the bloodstream?

    <p>Endocrine signaling</p> Signup and view all the answers

    What would likely occur if the parasympathetic system discharged as a complete entity?

    <p>It would lead to undesirable symptoms</p> Signup and view all the answers

    Which of the following is NOT considered a local mediator?

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

    What effect does vagal parasympathetic innervation have on the heart rate?

    <p>It decreases the heart rate</p> Signup and view all the answers

    What is the characteristic of dynamic antagonism in organ control?

    <p>It is fine-tuned at any given time</p> Signup and view all the answers

    What physiological changes result from sympathetic innervation when blood pressure drops?

    <p>Increased heart rate and vasoconstriction</p> Signup and view all the answers

    What is the primary role of efferent neurons in the autonomic nervous system?

    <p>Carrying signals from the brain to initiate an action</p> Signup and view all the answers

    Which of the following does NOT typically result from sympathetic stimulation?

    <p>Enhanced gastrointestinal motility</p> Signup and view all the answers

    Which response is triggered during emergencies by the sympathetic nervous system?

    <p>Fight or flight response</p> Signup and view all the answers

    What is one of the primary functions of the parasympathetic nervous system?

    <p>Maintaining homeostasis and digestive processes</p> Signup and view all the answers

    Which of the following statements about enteric neurons is true?

    <p>They control motility and secretions in the gut</p> Signup and view all the answers

    What happens to blood flow during sympathetic activation?

    <p>Diverted flow from the skin to muscles and heart</p> Signup and view all the answers

    What triggers the release of epinephrine during a sympathetic response?

    <p>Stimulation of the adrenal medulla</p> Signup and view all the answers

    What are the effects of sympathetic division stimulation?

    <p>Dilation of pupils and increased blood pressure</p> Signup and view all the answers

    What is the role of norepinephrine in the sympathetic nervous system?

    <p>It mediates the transmission of nerve impulses to effector organs.</p> Signup and view all the answers

    Which of the following systems is recognized as a second messenger system?

    <p>Calcium/phosphatidylinositol system</p> Signup and view all the answers

    Which protein is involved in the activation of adenylyl cyclase?

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

    What is one of the products released by phospholipase C in the calcium/phosphatidylinositol system?

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

    What occurs after a neurotransmitter binds to a receptor?

    <p>Intracellular signal translation into a cellular response begins.</p> Signup and view all the answers

    Which of the following describes a second messenger?

    <p>A molecule that transmits signals from receptors to target molecules within the cell.</p> Signup and view all the answers

    Activation of which protein subunit leads to the amplification of signals in the phosphatidylinositol system?

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

    What does diacylglycerol act as in intracellular signaling?

    <p>A second messenger that can activate specific protein targets</p> Signup and view all the answers

    What initiates the release of neurotransmitters at the nerve ending?

    <p>Arrival of the action potential</p> Signup and view all the answers

    Which neurotransmitter is commonly associated with cholinergic transmission?

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

    What characterizes adrenergic fibers?

    <p>They release norepinephrine or epinephrine</p> Signup and view all the answers

    Which of the following neurotransmitters is considered inhibitory?

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

    What is the role of increased intracellular Ca2+ in neurotransmitter release?

    <p>It triggers the fusion of synaptic vesicles with the presynaptic membrane</p> Signup and view all the answers

    During sympathetic system responses, which neurotransmitter is typically involved?

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

    In relation to neurotransmitter classification, what does cholinergic specifically refer to?

    <p>Involvement of acetylcholine</p> Signup and view all the answers

    Which neurotransmitter is involved in mediating the transmission at the autonomic ganglia?

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

    Study Notes

    Autonomic Nervous System (ANS) Overview

    • Efferent neurons transmit signals from the brain to initiate actions in the peripheral nervous system.
    • Afferent neurons sense environmental changes, conveying information from sensory receptors (e.g., visual, auditory).
    • Enteric neurons, often referred to as the "brain of the gut," function independently of the CNS, regulating gastrointestinal activity.

    Sympathetic Division Effects

    • Stimulation leads to increased heart rate and blood pressure, mobilizing energy and enhancing blood flow to skeletal muscles and the heart.
    • Results in dilation of pupils and bronchioles, impacting gastrointestinal motility and urinary and sexual organ functions.
    • Functions as part of the fight or flight response, activated during emergencies, involving both direct sympathetic stimulation and adrenal medulla epinephrine release.

    Parasympathetic Nervous System Functions

    • Primarily responsible for maintaining homeostasis and essential functions (e.g., digestion, waste elimination).
    • Generally counteracts sympathetic actions, dominating in "rest and digest" states.
    • Acts independently without full system discharge to prevent adverse effects, such as involuntary urination.

    Reflex Responses

    • Baroreceptors detect blood pressure drops, reducing signals sent to cardiovascular centers.
    • Triggers increased sympathetic output and decreased parasympathetic activity, resulting in elevated blood pressure and heart rate.

    Emotions and the ANS

    • Strong emotional stimuli (rage, fear, pleasure) can influence autonomic nervous system activity.

    Dual Innervation in Organs

    • Most organs receive innervation from both sympathetic and parasympathetic divisions.
    • For instance, vagal innervation slows heart rate, while sympathetic innervation increases it, allowing dynamic balance for homeostatic control.

    Organs with Sympathetic Only Innervation

    • Certain organs, including the adrenal medulla, kidneys, pilomotor muscles, and sweat glands, are innervated solely by the sympathetic system.
    • Blood pressure control is predominantly managed through sympathetic activities.

    Chemical Signaling Mechanisms

    • Hormones are secreted by endocrine cells into the bloodstream; local mediators act locally (e.g., histamine).
    • Neurotransmitters enable communication between nerve cells and effector organs, with release mechanisms involving Ca2+ influx.

    Types of Neurotransmitters

    • Acetylcholine: Mediates transmission for cholinergic neurons at autonomic ganglia, influencing both sympathetic and parasympathetic systems.
    • Norepinephrine and Epinephrine: Characterize adrenergic fibers in the sympathetic system, mediating communication from autonomic postganglionic neurons to effector organs.

    Second Messenger Systems

    • Second-messenger molecules, generated upon neurotransmitter-receptor binding, amplify cellular responses.
    • Common pathways include the adenylyl cyclase system and the calcium/phosphatidylinositol system, involving proteins like Gs and Gq for signal transduction.

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    Related Documents

    Sheet 3 ANS.pptx

    Description

    This quiz covers key concepts from Lecture 3 on the autonomic nervous system, focusing on drugs that affect its function. It explores the roles of efferent and afferent neurons and their significance in pharmacology. Test your understanding of how various drugs interact with the ANS.

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