أسئلة المحاضرة العاشرة فسيو (قبل التعديل)
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أسئلة المحاضرة العاشرة فسيو (قبل التعديل)

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Questions and Answers

What is the primary effect of sympathetic mass discharge?

  • Initiation of digestion
  • Generalized excitement across the body (correct)
  • Enhanced urinary function
  • Localized skin temperature reduction

    • Which of the following conditions could trigger sympathetic stimulation?

  • Relaxation techniques
  • Hypoglycemia (correct)
  • Seated rest
  • Meditation

    • How do parasympathetic cardiovascular reflexes primarily function?

  • They act exclusively on the heart. (correct)
  • They regulate sweating in the skin.
  • They affect whole body muscles.
  • They stimulate digestive enzyme production.

    • What is a consequence of parasympathetic mass stimulation?

    <p>Simultaneous emptying of bladder and rectum</p> Signup and view all the answers

    Which scenario would most likely cause prolonged GIT atony?

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

    What effect does the sympathetic nervous system have on muscle activity during stress?

    <p>It enhances capacity for vigorous muscular activity.</p> Signup and view all the answers

    What initiates the bladder emptying reflex?

    <p>Parasympathetic GIT reflex activation</p> Signup and view all the answers

    Which of the following is NOT associated with sympathetic stimulation?

    <p>Calm and relaxation</p> Signup and view all the answers

    What is the role of sympathetic tone at rest?

    <p>It causes a continuous basal discharge of sympathetic impulses.</p> Signup and view all the answers

    What happens to the heart rate when parasympathetic activity is increased?

    <p>It decreases to 70 beats per minute.</p> Signup and view all the answers

    What effect does cutting sympathetic nerves (sympathectomy) have on blood vessels?

    <p>It causes maximal vasodilatation initially.</p> Signup and view all the answers

    Which of the following statements about parasympathetic tone is correct?

    <p>It is responsible for maintaining normal motility in the GIT.</p> Signup and view all the answers

    During which state does sympathetic tone maintain arterial blood pressure?

    <p>At rest.</p> Signup and view all the answers

    What is a consequence of vagotomy in the heart?

    <p>The heart rate increases to 120 beats per minute.</p> Signup and view all the answers

    What influences gastrointestinal motility when sympathetic activity is heightened?

    <p>It decreases motility.</p> Signup and view all the answers

    How does cutting the parasympathetic nerve affect gastrointestinal activity?

    <p>It reduces gastrointestinal motility.</p> Signup and view all the answers

    What effect does sympathetic mass stimulation have on the pupils during stress?

    <p>Pupillary dilatation</p> Signup and view all the answers

    How does sympathetic stimulation affect heart function?

    <p>Accelerates heart rate and increases myocardial contraction</p> Signup and view all the answers

    What physiological change occurs in the bronchioles during sympathetic activation?

    <p>Dilation of bronchioles</p> Signup and view all the answers

    Which effect relates to the blood vessels during sympathetic mass stimulation?

    <p>Vasoconstriction in skin and vasodilation in skeletal muscles</p> Signup and view all the answers

    What is the effect of sympathetic stimulation on skeletal muscle contraction?

    <p>Increased strength of contraction and delayed fatigue</p> Signup and view all the answers

    What role does the spleen play during sympathetic mass stimulation?

    <p>Ejects red blood cells into circulation</p> Signup and view all the answers

    What effect does adrenaline have on blood glucose levels during stress?

    <p>Elevates blood glucose levels</p> Signup and view all the answers

    During sympathetic activation, what happens to sweat secretion?

    <p>Increases evaporation leading to increased heat loss</p> Signup and view all the answers

    What is a defining characteristic of sympathetic stimulation in isolated portions of the system?

    <p>It can be localized to specific organs like skin blood vessels.</p> Signup and view all the answers

    Which reflex serves as an example of parasympathetic influence on gastrointestinal functions?

    <p>Salivary secretion initiating gastric activity.</p> Signup and view all the answers

    In which scenario would a state of sympathetic mass discharge most likely occur?

    <p>In response to severe exercise or pain.</p> Signup and view all the answers

    What is the primary consequence of parasympathetic mass stimulation?

    <p>Facilitation of bladder and rectal emptying.</p> Signup and view all the answers

    What is a result of sympathetic mass stimulation during stress responses?

    <p>Enhanced ability to perform vigorous muscular activity.</p> Signup and view all the answers

    Which statement accurately describes the association between parasympathetic functions?

    <p>One reflex can trigger another closely related reflex.</p> Signup and view all the answers

    How does the body react to the sympathetic response during emergency situations?

    <p>Experiencing generalized sympathetic excitement.</p> Signup and view all the answers

    What physiological change takes place in the sweat glands due to sympathetic stimulation during stress?

    <p>Increased secretion to enhance grip.</p> Signup and view all the answers

    What is the primary physiological role of sympathetic tone at rest?

    <p>It maintains mild activity in supplied organs.</p> Signup and view all the answers

    What happens to the heart rate when parasympathetic activity decreases?

    <p>It increases heart rate to 120 beats/min.</p> Signup and view all the answers

    What is the initial effect of symapathectomy on blood vessels?

    <p>It causes immediate maximal vasodilatation.</p> Signup and view all the answers

    What physiological change occurs in the gastrointestinal tract with increased parasympathetic activity?

    <p>Increased motility and digestive secretions.</p> Signup and view all the answers

    What effect does cutting parasympathetic nerves (vagotomy) have on heart rate?

    <p>Increases heart rate from 70 to 120 beats/min.</p> Signup and view all the answers

    What long-term effect does cutting the sympathetic nerve have on arterial blood pressure?

    <p>It results in intrinsic restoration of vasoconstriction.</p> Signup and view all the answers

    What physiological response is most associated with the constriction of blood vessels in the skin during sympathetic mass stimulation?

    <p>Reduction of blood loss</p> Signup and view all the answers

    Which process is increased in the liver during sympathetic mass stimulation to provide more energy?

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

    How does sympathetic activity affect the diameter of blood vessels?

    <p>It decreases their maximal diameter by half.</p> Signup and view all the answers

    What is the primary effect of adrenaline secretion on metabolism during stress?

    <p>Elevates blood glucose levels</p> Signup and view all the answers

    What is a key factor involved in the regulation of sympathetic tone?

    <p>Continuous afferent impulses from baroreceptors.</p> Signup and view all the answers

    During sympathetic activation, what happens to the strength of skeletal muscle contraction?

    <p>It strengthens and delays fatigue</p> Signup and view all the answers

    What effect does sympathetic mass stimulation have on bronchioles to enhance respiratory function?

    <p>Dilates bronchioles</p> Signup and view all the answers

    How does the contraction of the splenic capsule during sympathetic activation affect blood volume?

    <p>Ejects blood into general circulation</p> Signup and view all the answers

    In the context of sympathetic stimulation, what is the role of exophthalmos?

    <p>Increases field of vision</p> Signup and view all the answers

    What is the overall effect of sympathetic mass stimulation on the cardiovascular system during stress?

    <p>Increases heart rate and myocardial contraction force</p> Signup and view all the answers

    Study Notes

    Sympathetic and Parasympathetic Tone at Rest

    • Sympathetic Tone
      • Continuous discharge of impulses to organs, leading to mild activity
      • Causes:
        • Continuous basal discharge of sympathetic impulses
        • Continuous basal secretion of adrenaline and noradrenaline from the adrenal medulla
        • Sympathetic supply to blood vessels causes partial vasoconstriction, maintaining normal arterial blood pressure
    • Parasympathetic Tone
      • Continuous discharge of impulses to organs, leading to mild activity
      • Causes:
        • Continuous basal discharge of parasympathetic impulses
        • Continuous afferent impulses from baroreceptors in the carotid sinus and aortic arch along sinus and aortic nerves to the cardioinhibitory center in the medulla oblongata
      • Effects:
        • Decreases heart rate from 120 to 70 beats per minute
        • Maintains normal gastrointestinal motility

    Cutting Nerves

    • Sympathectomy (Cutting Sympathetic Nerves)
      • Leads to immediate maximal vasodilatation
      • After some time, intrinsic tone of smooth muscle in blood vessels increases, restoring vasoconstriction and returning normal arterial blood pressure
    • Vagotomy (Cutting Parasympathetic Nerves)
      • Effects:
        • Increases heart rate from 70 to 120 beats per minute
        • Leads to prolonged gastrointestinal atony

    Sympathetic and Parasympathetic Stimulation in Specific Organs

    • Sympathetic Stimulation
      • Affects isolated portions of the body, like skin blood vessels during hot weather or hand sweating during writing
    • Parasympathetic Stimulation
      • Cardiovascular Reflexes: Act only on the heart
      • Gastrointestinal Reflexes: Act only on the gastrointestinal tract

    Sympathetic Mass Discharge (Stress Response)

    • Causes:
      • Emergency or stress conditions like hemorrhage, hypoglycemia, severe cold, pain, severe exercise, fear, fight, flight, and emotions
    • Effects:
      • Enables the body to face stressful situations
      • Increases the body's capacity for vigorous muscular activity
    • Specific Effects:
      • Eyes: Pupillary dilatation, exophthalmos, widening of the palpebral fissure
      • Heart: Increased heart rate, force of contraction, and blood pressure, supplying blood to vital organs and muscles
      • Thorax: Bronchodilation for increased lung ventilation and oxygen supply
      • Somatic: Vasoconstriction in the skin to limit bleeding, vasodilation of skeletal and cardiac muscle blood vessels, increased muscle contraction strength, delayed fatigue
      • Spleen: Contraction of the splenic capsule, ejecting red blood cells into circulation, increasing blood volume and oxygen carrying capacity
      • Adrenal Medulla: Secretion of adrenaline and noradrenaline potentiates sympathetic stimulation
      • Liver: Increases glycogenolysis and glycolysis
      • Other: Increased sweat secretion for heat loss

    Parasympathetic Mass Stimulation

    • Fatal
    • Causes: Association between closely related parasympathetic functions, where one reflex can initiate another
    • Effects:
      • Rectal Emptying Reflex: Initiates bladder emptying reflex, leading to simultaneous emptying of the bladder and rectum
      • Salivary Secretion: Activates gastric secretion
      • Gastric Secretion: Activates pancreatic secretions

    Sympathetic Mass Stimulation Effects During Stress

    • Increased Mental Activity and Cellular Metabolism
    • Orbelli Phenomenon: Delay in the onset of muscle fatigue during stress
    • Sympatho-Adrenal System: Adrenaline and noradrenaline secretion potentiates sympathetic stimulation
    • Energy Supply: Increased blood glucose and free fatty acid levels
    • Glycogenolysis & Glycolysis: Increased glycogenolysis in the liver and glycolysis in the muscle
    • Heat Loss: Increased sweat secretion for heat loss

    Sympathetic & Parasympathetic Tone

    • At rest, both the sympathetic and parasympathetic nervous systems have a continuous basal discharge, known as tone.
    • Sympathetic tone:
      • Leads to mild activity in organs due to continuous sympathetic nerve discharge.
      • Causes:
        • Continuous basal secretion of adrenaline & noradrenaline from the adrenal medulla.
        • Vasoconstriction in blood vessels, maintaining normal arterial blood pressure.
    • Parasympathetic tone:
      • Leads to mild activity in organs due to continuous parasympathetic nerve discharge.
      • Causes:
        • Continuous afferent impulses from baroreceptors in the carotid sinus and aortic arch, transmitted via the sinus & aortic nerves to the cardioinhibitory center in the medulla oblongata.
      • Effects:
        • Heart: Decreases heart rate from 120 beats/min to 70 beats/min.
        • Gastrointestinal tract (GIT): Maintains normal motility.

    Cutting of Nerves

    • Sympathectomy (Cutting sympathetic nerves):
      • Leads to immediate maximal vasodilatation.
      • After some time, intrinsic tone of smooth muscles in blood vessels increases, restoring vasoconstriction and returning arterial blood pressure to normal.
    • Vagotomy (Cutting parasympathetic nerves):
      • Heart: Increases heart rate from 70 to 120 beats/min.
      • GIT: Leads to prolonged GIT atony (loss of muscle tone).

    Localized Effects

    • Sympathetic stimulation can occur in isolated portions of the body.
      • Examples:
        • Hot weather: Affects only skin blood vessels and sweat glands, without affecting other organs.
        • Handwriting: Sweat secretion occurs only in the hand for a better grip.
    • Parasympathetic stimulation often acts on specific organ systems.
      • Examples:
        • Cardiovascular reflexes: Act only on the heart.
        • GIT reflexes: Act only on the gastrointestinal tract.

    Mass Actions (Generalized Effects)

    • Sympathetic mass discharge (stress response):
      • Occurs in emergency or stress conditions such as hemorrhage, hypoglycemia, severe cold, pain, severe exercise, fear, fight, flight, and emotions.
      • Effects:
        • Pupillary dilatation (widening of pupils)
        • Exophthalmos (bulging eyes)
        • Increased heart rate
        • Increased force of myocardial contraction
        • Increased blood pressure
        • Bronchodilation (widening of airways)
        • Vasoconstriction in the skin
        • Vasodilation in skeletal muscles and cardiac muscle
        • Increased skeletal muscle strength
        • Splenic contraction, releasing red blood cells into circulation
        • Secretion of adrenaline and noradrenaline, potentiating sympathetic system stimulation (sympatho-adrenal system)
        • Increased blood glucose and free fatty acid levels
        • Increased glycogenolysis in the liver
        • Increased glycolysis in muscles
        • Increased mental activity
        • Increased cellular metabolism
        • Increased sweat secretion
    • Parasympathetic mass stimulation:
      • Fatal
      • Associated with closely related functions: One parasympathetic reflex can initiate another.
      • Examples:
        • Rectal emptying reflex initiates bladder emptying reflex, leading to simultaneous emptying of both.
        • Salivary stimulation activates gastric secretion, which then activates pancreatic secretions.

    Sympathetic Mass Stimulation During Stress

    • Eye: Pupillary dilatation, exophthalmos, and widening of the palpebral fissure (eyelid opening) for an increased field of vision.
    • Heart: Increased heart rate, increased force of myocardial contraction, and elevated blood pressure, directing increased blood flow to vital organs and active muscles.
    • Thorax: Bronchodilation for better lung ventilation and oxygen supply.
    • Somatic System: Vasoconstriction in the skin to limit bleeding, vasodilation in skeletal and cardiac muscles, shifting blood flow to active areas. Increased skeletal muscle strength and delayed fatigue (Orbelli Phenomenon).
    • Spleen: Contraction of the splenic capsule, releasing red blood cells into circulation to increase blood volume and oxygen-carrying capacity.
    • Adrenal Medulla: Secretion of adrenaline and noradrenaline, potentiating the stimulation of the sympathetic system (sympatho-adrenal system).
    • Liver: Increased glycogenolysis and glycolysis, providing energy for active muscles.
    • Other: Increased sweat secretion for heat loss through evaporation, increased mental activity and cellular metabolism throughout the body.

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