Autonomic Nervous System Quiz
55 Questions
1 Views

Autonomic Nervous System Quiz

Created by
@yahiaakeely

Podcast Beta

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which of the following is NOT a function regulated by the autonomic nervous system?

  • Urinary bladder emptying
  • GI motility
  • Body temperature
  • Visual acuity (correct)

    • What are the two major subdivisions through which efferent autonomic signals are transmitted?

  • Cranial and spinal nerves
  • Central and peripheral nervous systems
  • Sensory and motor pathways
  • Sympathetic and parasympathetic systems (correct)

    • Which of the following bodily functions is primarily influenced by the sympathetic nervous system?

  • Decreased heart rate
  • Bladder contraction
  • Sweating (correct)
  • GI secretion

    • Which physiological parameters are affected by the autonomic nervous system?

    <p>Heart rate and arterial pressure</p> Signup and view all the answers

    What role does GI motility play in the autonomic nervous system?

    <p>Increases during parasympathetic activation</p> Signup and view all the answers

    From which areas do parasympathetic nerve fibers primarily originate?

    <p>Sacral spinal cord and brain stem</p> Signup and view all the answers

    Which part of the brain is NOT involved in the origin of parasympathetic nerve fibers?

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

    The term 'craniosacral' in the context of parasympathetic nerve fibers refers to their origin in which regions?

    <p>Cranial and sacral areas of the body</p> Signup and view all the answers

    Which of the following statements about parasympathetic nerve fibers is accurate?

    <p>They arise from the brain stem and sacral spinal cord.</p> Signup and view all the answers

    How do the locations of origin for parasympathetic fibers differ from those of sympathetic fibers?

    <p>Parasympathetic fibers originate in specific areas of the brain stem and sacrum.</p> Signup and view all the answers

    What type of fibers secrete norepinephrine?

    <p>Postganglionic sympathetic fibers</p> Signup and view all the answers

    Which statement correctly characterizes postganglionic parasympathetic fibers?

    <p>They are known as cholinergic.</p> Signup and view all the answers

    Which of the following fibers does NOT secrete norepinephrine?

    <p>Fibers to sweat glands</p> Signup and view all the answers

    What neurotransmitter is secreted by postganglionic parasympathetic fibers?

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

    Which type of fibers are classified as adrenergic?

    <p>Sympathetic postganglionic fibers</p> Signup and view all the answers

    Which type of receptors bind to acetylcholine and are located on postganglionic cell membranes?

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

    What blocks the activity of nicotinic receptors?

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

    Which of the following receptor types initiates the opening of non-specific cation channels upon activation by acetylcholine?

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

    What type of neurotransmitter do adrenergic receptors primarily bind to?

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

    Which of the following compounds activates muscarinic receptors?

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

    Which type of receptors do sympathetic postganglionic nerve endings primarily act on?

    <p>Both α and β receptors</p> Signup and view all the answers

    What is the primary action of sympathetic postganglionic nerve endings?

    <p>To stimulate the heart rate</p> Signup and view all the answers

    Which of the following statements about sympathetic postganglionic actions is correct?

    <p>They interact with both α and β receptors.</p> Signup and view all the answers

    What type of physiological response is likely mediated by α receptors activated by sympathetic postganglionic fibers?

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

    Which of the following is NOT a characteristic of sympathetic postganglionic nerve action?

    <p>Promotes rest-and-digest functions</p> Signup and view all the answers

    What effect do adrenergic receptors have on the heart?

    <p>They can increase heart rate and contractility.</p> Signup and view all the answers

    Which statement correctly describes the effect of adrenergic receptors on blood vessels?

    <p>They cause vasoconstriction but also promote vasodilation in certain conditions.</p> Signup and view all the answers

    Which of the following effects is associated with the stimulation of adrenergic receptors in the human body?

    <p>Increased heart rate and blood pressure.</p> Signup and view all the answers

    What is the primary role of adrenergic receptors in the vascular system?

    <p>To manage blood vessel constriction and dilation.</p> Signup and view all the answers

    How do adrenergic receptors affect overall cardiovascular function?

    <p>They enhance cardiovascular efficiency during stress responses.</p> Signup and view all the answers

    What is the primary action of an agonist in the autonomic nervous system?

    <p>Binds to neurotransmitter’s receptor and mimics its action</p> Signup and view all the answers

    Which of the following effects is associated with a more potent pressor action?

    <p>Contraction of the skeletal muscle blood vessels</p> Signup and view all the answers

    What is the expected effect of an agonist on gastrointestinal (GI) motility?

    <p>Decrease overall motility</p> Signup and view all the answers

    What differentiates the relaxing effects on the gastrointestinal tract from the more pressor actions?

    <p>Relaxing effects are induced through parasympathetic stimulation</p> Signup and view all the answers

    Which of the following statements accurately describes an agonist's function?

    <p>Mimics the effects of a neurotransmitter when binding to its receptor</p> Signup and view all the answers

    Which of the following statements about nicotinic receptors is accurate?

    <p>They bind to acetylcholine endogenously and nicotine exogenously.</p> Signup and view all the answers

    What kind of agents can block muscarinic receptors?

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

    Which type of receptor initiates the opening of non-specific cation channels upon activation?

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

    What neurotransmitter do adrenergic receptors primarily bind to?

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

    Which receptor type is located on postganglionic cell membranes?

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

    What neurotransmitter is secreted by both preganglionic sympathetic and parasympathetic fibers?

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

    Which of the following correctly describes the classification of preganglionic fibers in the autonomic nervous system?

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

    Which characteristic is true regarding the neurotransmitters of the autonomic nervous system?

    <p>Preganglionic parasympathetic fibers secrete acetylcholine</p> Signup and view all the answers

    What distinguishes cholinergic fibers in the autonomic nervous system?

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

    Which statement accurately reflects the function of preganglionic autonomic fibers?

    <p>They secrete acetylcholine to stimulate postganglionic neurons</p> Signup and view all the answers

    What neurotransmitter is primarily secreted by postganglionic sympathetic fibers?

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

    Which type of postganglionic fibers are responsible for secreting acetylcholine?

    <p>Cholinergic fibers</p> Signup and view all the answers

    Which statement accurately reflects the function of postganglionic sympathetic fibers?

    <p>They secrete norepinephrine, except for fibers to sweat glands.</p> Signup and view all the answers

    Which of the following is a characteristic of cholinergic fibers?

    <p>They secrete acetylcholine.</p> Signup and view all the answers

    What distinguishes the fibers that innervate sweat glands from other postganglionic sympathetic fibers?

    <p>They secrete acetylcholine instead of norepinephrine.</p> Signup and view all the answers

    What neurotransmitter is primarily secreted by postganglionic sympathetic fibers?

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

    Which type of postganglionic fibers are known to secrete acetylcholine?

    <p>Cholinergic fibers</p> Signup and view all the answers

    What is the primary difference between postganglionic sympathetic fibers and those innervating sweat glands?

    <p>Fibers to sweat glands do not secrete norepinephrine.</p> Signup and view all the answers

    Which classification of fibers secretes norepinephrine?

    <p>Postganglionic sympathetic fibers</p> Signup and view all the answers

    Which statement accurately describes postganglionic parasympathetic fibers?

    <p>They are cholinergic and secrete acetylcholine.</p> Signup and view all the answers

    Study Notes

    Autonomic Nervous System

    • The efferent autonomic signals are transmitted to different organs through two major subdivisions: the sympathetic and parasympathetic nervous systems.
    • Signals travel from the brain stem (midbrain, pons, and medulla) or the sacral spinal cord for the parasympathetic system.
    • Preganglionic fibers originate from nuclei of cranial nerves (CN) III, VII, IX, and X, or from sacral spinal segments S2-S4.
    • The parasympathetic system acts as one unit, with generalized action producing a catabolic effect that delays visceral content evacuation.

    Parasympathetic System

    • Parasympathetic system originates from the brain stem (midbrain, pons, and medulla) or the sacral spinal cord (craniosacral).
    • Postganglionic fibers always secrete acetylcholine (Ach).
    • The actions of acetylcholine stimulate nicotinic or muscarinic receptors in the postganglionic fibers.
    • The parasympathetic system controls:
      • Arterial pressure
      • Heart rate
      • GI motility
      • GI secretion
      • Urinary bladder emptying
      • Sweating
      • Body temperature

    Autonomic Nervous System Neurotransmitters

    • Postganglionic sympathetic fibers release norepinephrine (except for sweat glands which release acetylcholine).
    • Postganglionic parasympathetic fibers release acetylcholine.

    Cholinergic Receptors

    • Nicotinic receptors are found on postganglionic cell bodies of all autonomic ganglia.
      • They are activated by acetylcholine (endogenous) and nicotine (exogenous).
      • They are blocked by curare and hexamethonium.
    • Muscarinic receptors are found on effector cell membranes.
      • They are activated by acetylcholine (endogenous) and muscarine (exogenous).
      • They are blocked by atropine.

    Adrenergic Receptors

    • Alpha (α) receptors and beta (β) receptors bind to norepinephrine and epinephrine.

    ### Properties of Cholinergic Receptors

    • Nicotinic receptors: binding of acetylcholine to these receptors initiates opening of non-specific cation channels.
    • Muscarinic receptors: binding of acetylcholine to these receptors activates G-protein coupled signaling pathways which lead to a variety of effects.

    Autonomic Agonists and Antagonists

    • Agonists: bind to neurotransmitter receptors and cause the same response as the neurotransmitter would.
    • Antagonists: bind to neurotransmitter receptors and block the action of the neurotransmitter.

    Autonomic Neurotransmitters

    • Preganglionic sympathetic and parasympathetic fibers are cholinergic as they secrete acetylcholine
    • Post ganglionic sympathetic fibers are adrenergic as they secrete norepinephrine, except those fibers to sweat glands, which are cholinergic
    • Post ganglionic parasympathetic fibers are cholinergic as they secrete acetylcholine

    Autonomic Neurotransmitter Receptors

    • Tissues innervated by the autonomic nervous system have different receptor types for postganglionic chemical messengers
    • Cholinergic receptors bind to acetylcholine
      • Nicotinic receptors are found on postganglionic cell bodies of all autonomic ganglia
      • Muscarinic receptors are found on effector cell membranes
    • Adrenergic receptors bind to norepinephrine and epinephrine
      • Alpha (α) receptors
      • Beta (β) receptors

    Nicotinic Receptors

    • Activated by acetylcholine endogenously and nicotine exogenously
    • Blocked by curare and hexamethonium

    Muscarinic Receptors

    • Activated by acetylcholine endogenously and muscarine exogenously
    • Blocked by atropine

    Properties of Cholinergic Receptors

    • Nicotinic receptors: binding of Ach to these receptors initiates opening of non-specific cation channels
    • Adrenergic receptors: binding of norepinephrine and epinephrine causes a variety of effects:
      • Effect on the Heart: Strong effect on the heart (by β1 receptors) are stronger than on the blood vessels (by β2 receptors)
      • Effect on the Blood Vessels:
        • Alpha receptors cause vasoconstriction
        • Beta receptors cause vasodilation
        • β2 agonists (e.g. Salbutamol) are used as bronchodilators
      • Antagonists: bind with the receptor preventing the neurotransmitter from binding and causing a response
        • e.g. Atropine is a muscarinic antagonist
        • e.g. Propranolol is a β blocker
        • e.g. Phenylephrine is an alpha agonist

    Autonomic Nervous System

    • Sympathetic postganglionic fibers are adrenergic and secrete norepinephrine (except for fibers to sweat glands).
    • Parasympathetic postganglionic fibers are cholinergic and secrete acetylcholine.
    • Cholinergic receptors bind to acetylcholine. There are two types:
      • Nicotinic receptors found on postganglionic cell bodies of all autonomic ganglia.
      • Muscarinic receptors found on effector cell membranes.
    • Adrenergic receptors bind to norepinephrine and epinephrine. There are two types:
      • Alpha (α) receptors.
      • Beta (β) receptors.

    Nicotinic Receptors

    • Activated by acetylcholine endogenously and nicotine exogenously.
    • Blocked by curare and hexamethonium.

    Muscarinic Receptors

    • Activated by acetylcholine endogenously and muscarine exogenously.
    • Blocked by atropine.

    Properties of Cholinergic Receptors

    • Nicotinic receptors: binding of Ach to these receptors initiates opening of non-specific cation channels.
    • Muscarinic receptors: binding of Ach initiates G protein-linked receptors pathways, depending on the effector organ.

    Properties of Adrenergic Receptors

    • α1 & α2 receptors have greater sensitivity to norepinephrine.
    • β2 receptors bind exclusively with epinephrine.
    • β1 receptors have equal affinity for epinephrine and norepinephrine.
    • All adrenergic receptors are linked to G protein.
      • Activation of β1 & β2 activates cAMP.
      • Activation of α1 activates IP3 /Ca2+.
      • Activation of α2 inhibits cAMP in target cells.

    Effect of ANS on Various Organs

    Organ Sympathetic Parasympathetic
    Heart + (increase heart rate and contractility) - (decrease heart rate)
    Blood Vessels Constrict (most organs) Dilate (penis and clitoris)
    Blood Vessels (Skeletal Muscles) Dilate
    Bronchioles Dilate Constrict
    Pupil Dilate Constrict
    Digestion Inhibit Enhance

    Norepinephrine and Epinephrine

    • Norepinephrine is secreted by:
      • Adrenal medulla (80% of its secretion).
      • Sympathetic postganglionic nerve endings.
    • Epinephrine is secreted by:
      • Adrenal medulla (20% of its secretion).
    • Norepinephrine acts on both α and β receptors.
    • Epinephrine mainly acts on α receptors.
    • Salbutamol is a β2 agonist (bronchodilator).
    • Antagonists bind to the receptor and prevent the neurotransmitter from binding and causing a response.

    Studying That Suits You

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

    Quiz Team

    Related Documents

    Autonomic Nervous System-I PDF
    Autonomic Nervous System-II L15 PDF

    Description

    Test your knowledge of the autonomic nervous system, focusing on the sympathetic and parasympathetic divisions. This quiz covers the origin of fibers, neurotransmitters, and physiological functions. Perfect for students of neurology or physiology!

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser