Trigeminal Reflexes and Cardiovascular Function
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Questions and Answers

Which reflex is NOT mentioned as being studied in relation to the trigeminal nerve?

  • Trigeminal reflex
  • Diving reflex
  • Trigeminocardiac reflex
  • Facial reflex (correct)

    • The heart is solely innervated by the sympathetic nervous system.

    False

    What type of nervous reflexes are induced by the trigeminal nerve affecting cardiovascular function?

    Somato-autonomic nervous reflexes

    The heart's function during trigeminal reflexes is regulated by an increased __________ response.

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

    Match the following reflexes with their characteristics:

    <p>Diving reflex = Causes bradycardia and decreased heart rate Trigemino-Cardiac reflex = Involves facial nerve stimulation and cardiovascular response Trigeminal reflex = Rapid changes in cardiovascular function due to somato-autonomic response</p> Signup and view all the answers

    What is the main role of the trigeminal nerve in cardiovascular responses?

    <p>It induces rapid cardiovascular changes through somato-autonomic reflexes.</p> Signup and view all the answers

    The sympathetic activity during trigeminal reflexes can be increased, decreased, or remain unchanged.

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

    The combination of increased parasympathetic and __________ activity regulates cardiac function during trigeminal reflexes.

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

    What is the primary function of the diving response in humans?

    <p>To protect against hypoxic damage</p> Signup and view all the answers

    The trigeminocardiac reflex can occur during surgery in the cerebellopontine angle.

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

    What nerve is essential for initiating the nasopharyngeal response in rats?

    <p>anterior ethmoidal nerve</p> Signup and view all the answers

    The diving bradycardia mechanism is part of the __________ reflex.

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

    Match the authors with their contributions related to trigeminocardiac reflexes:

    <p>Lang S = Defense against hypoxic damage Rybka EJ = Initiation of nasopharyngeal response Schaller B = Surgery in the cerebellopontine angle Gooden BA = Mechanisms of the human diving response</p> Signup and view all the answers

    What does the research by Hollandsworth et al. focus on?

    <p>Activation of the medullary dorsal horn by nasal stimulation</p> Signup and view all the answers

    Coronary vasospasm can occur during percutaneous trigeminal rhizotomy.

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

    What effect does intense vasoconstriction have during the diving reflex?

    <p>Stops blood flow to peripheral capillary beds</p> Signup and view all the answers

    The diving reflex is equally effective in humans as it is in natural diving animals.

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

    What is the role of the ethmoidal nerve in the nasopharyngeal reflex?

    <p>Innervates the nasal passages and external nares</p> Signup and view all the answers

    The diving reflex is one of the most powerful ________ reflexes of the organism.

    <p>somato-autonomic</p> Signup and view all the answers

    Match the following components of the diving reflex with their effects:

    <p>Vasoconstriction = Reduces blood flow to peripheral capillaries Increased sympathetic tone = Preserves blood pressure Reduced heart rate = Decreases cardiac output Nasal irritation = Activates the nasopharyngeal reflex</p> Signup and view all the answers

    What potential risks do patients undergoing surgical interventions in the trigeminal territory face?

    <p>Cardiovascular depression</p> Signup and view all the answers

    The sympathetic response of the diving reflex in humans may significantly increase blood pressure.

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

    What substances can activate the nasopharyngeal reflex?

    <p>Irritating gases, water, or electrical stimulation</p> Signup and view all the answers

    The ________ reflex is activated by stimulating the nasal mucosa.

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

    In diving animals like seals, what is a primary effect of the diving reflex?

    <p>Increased sympathetic tone</p> Signup and view all the answers

    What is the trigeminocardiac reflex associated with?

    <p>Reduction in heart rate</p> Signup and view all the answers

    The trigeminocardiac reflex was first described in the year 1988.

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

    What physiological response is produced by the stimulation of the trigeminal branches?

    <p>Reflex cardiovascular symptoms, including hypotension and bradycardia</p> Signup and view all the answers

    In 1975, Kumada et al. observed a reflex that induced gastrointestinal symptoms including gastric __________.

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

    Match the researchers with their contributions regarding trigeminal reflexes:

    <p>Aschner = Described heart rate reduction due to eyeball compression Shelly and Church = Suggested the term trigeminocardiac reflex Lang et al. = Described intense reflex bradycardia Kumada et al. = Studied respiratory effects</p> Signup and view all the answers

    What did Shelly and Church propose in relation to the trigeminal reflex?

    <p>The term 'trigeminocardiac reflex'</p> Signup and view all the answers

    The trigeminovagal reflex is characterized by a decrease in vagal tone.

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

    What type of response occurs with low frequency stimulation in the trigeminal reflex?

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

    The central occurrence of the trigeminovagal reflex was first published by __________ and colleagues.

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

    Which of these symptoms is NOT associated with the trigeminal reflex?

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

    What effect does the nasopharyngeal reflex have on sympathetic tone?

    <p>Increases sympathetic tone</p> Signup and view all the answers

    The trigeminal reflex is known to decrease blood pressure in patients with cardiovascular diseases.

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

    What are two significant hemodynamic changes induced by trigeminal reflexes?

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

    The nasopharyngeal reflex is considered a powerful oxygen-preserving __________.

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

    Match the following complications with their related factors:

    <p>Coronary spasms = Key factor in pathophysiology of complications Asystole = Severe arrhythmia induced by trigeminocardiac reflex Ventricular fibrillation = Complication observed during neurosurgeries Bradycardia = Common cardiovascular response elicited by reflexes</p> Signup and view all the answers

    What physiological process is primarily affected by the sympathetic/parasympathetic interaction during trigeminal reflexes?

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

    The diving reflex and the nasopharyngeal reflex have no common characteristics.

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

    How might cholinergic discharge affect coronary arteries in patients with atherosclerosis?

    <p>It could trigger paradoxical vasoconstriction.</p> Signup and view all the answers

    The changes in vascular flow at the carotid level suggest blood flow redistribution to the __________.

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

    What potential complication might arise as a consequence of the trigeminocardiac reflex during neurosurgeries?

    <p>Severe arrhythmias</p> Signup and view all the answers

    Study Notes

    Trigeminal Reflexes and Cardiovascular Function

    • Trigeminal nerve and heart are strongly connected through somato-autonomic reflexes, inducing rapid cardiovascular changes.
    • Diving and trigeminocardiac reflexes are the most studied trigeminal reflexes.
    • The heart receives dual innervation (sympathetic and parasympathetic), influencing how cardiovascular function is regulated during trigeminal reflexes.
    • These reflexes involve a combination of increased parasympathetic response and varying sympathetic activity.
    • Hemodynamic changes (e.g., heart rate, blood pressure) result from these autonomic alterations.
    • In oxygen-conserving reflexes (e.g., diving reflex), co-activation of sympathetic and parasympathetic systems reduces heart rate and maintains/increases blood pressure.
    • Trigeminocardiac reflex often involves bradycardia and hypotension due to parasympathetic activation and sympathetic inhibition.
    • Sudden cardiac innervation disturbances can cause arrhythmias or myocardial ischemia, especially during surgeries in the trigeminal territory.

    Diving Reflex

    • Oxygen deprivation (even brief) can be harmful, but many species (birds, mammals, humans) have adapted to withstand hypoxia/anoxia.
    • Diving reflex is a key adaptation, triggering heart rate reduction (via vagal activation), increased blood pressure (via sympathetic response), and apnea.
    • Apnea can be voluntary (breath-holding) or reflexive (cold receptor stimulation on face, eyes, and nasal cavity).
    • Facial submersion rapidly triggers these responses.

    Trigeminocardiac Reflex

    • Clinically and experimentally proven brainstem reflex.
    • Characterized by hypotension (20% drop in mean arterial blood pressure), bradycardia (<60 bpm) and response to trigeminal manipulation/disturbances.
    • May lead to asystole in severe cases.
    • Classified into central (ganglion to nucleus) and peripheral (peripheral divisions to ganglion) subtypes.
    • Peripheral reflex can be further divided into ophthalmocardiac and maxillomandibulocardiac reflexes.

    Other Reflexes

    • Nasopharyngeal reflex: activated by irritating stimuli, water, or electrical stimulation.
    • Oculocardiac reflex: triggered by physical stimulation of eyes or adnexa.
    • Nasopharyngeal reflex involves increased parasympathetic tone (reduces heart rate and cardiac output) and increased sympathetic tone (greater peripheral vascular resistance), maintaining stable blood pressure.
    • Trigeminal reflex responses vary based on stimulus type, intensity, frequency, duration, involved nerve fibers, and analgesic/anesthetic use.

    Hemodynamic Changes During Trigeminal Reflexes

    • Bradycardia and blood pressure modifications are prominent.
    • Sudden changes can affect patients with cardiovascular issues.
    • Potential for arrhythmias, asystole, and ventricular fibrillation during neuro-surgeries.
    • Coronary spasm a potential factor in complications.
    • Co-activation of sympathetic systems may reduce blood flow in damaged areas of the heart.

    Conclusion

    • Trigeminal nerve stimulation triggers hemodynamic changes through somato-autonomic reflexes (e.g., diving, trigeminocardiac)
    • Hemodynamic changes are influenced by sympathetic/parasympathetic balance, stimulus factors, and other variables (e.g. anesthesia).
    • These reflexes and resulting disturbances are clinically relevant, requiring proper management during surgeries in the trigeminal territory.

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    Description

    Explore the intricate relationship between trigeminal reflexes and cardiovascular function. This quiz covers the mechanisms of somato-autonomic reflexes, including the diving reflex and trigeminocardiac reflex. Understand how these reflexes impact heart rate and blood pressure through dual innervation.

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