أسئلة الثامنة فسيو (بعد التعديل)
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Questions and Answers

Which cranial nerve is responsible for controlling pupillary constriction?

  • Vagus Nerve
  • Glossopharyngeal Nerve
  • Occulomotor Nerve (correct)
  • Facial Nerve

    • What is the primary function of the ciliary muscle?

  • Pupillary dilation
  • Salivation
  • Respiration regulation
  • Accommodation for near vision (correct)

    • Which branch of the Facial Nerve is responsible for salivary secretion?

  • Chorda Tympani (correct)
  • Vagus Nerve
  • Greater Superficial Petrosal
  • Glossopharyngeal Nerve

    • Which nucleus in the pons is associated with the Greater Superficial Petrosal Nerve?

    <p>Superior Salivary Nucleus</p> Signup and view all the answers

    Which of the following is NOT a function of the parasympathetic nervous system?

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

    What ganglion is associated with the Glossopharyngeal Nerve?

    <p>Otic Ganglion</p> Signup and view all the answers

    Where is the pelvic component of the parasympathetic nervous system primarily located?

    <p>Sacral segments 2, 3, 4</p> Signup and view all the answers

    Which of the following glands is innervated by the Facial Nerve?

    <p>Lacrimal Gland</p> Signup and view all the answers

    What is the primary effect of parasympathetic stimulation on the pupils during near vision tasks, such as reading?

    <p>Decreases pupil size</p> Signup and view all the answers

    What is one of the functions of the parasympathetic nervous system related to the gastrointestinal tract?

    <p>Stimulation of pancreatic secretion</p> Signup and view all the answers

    What effect does parasympathetic stimulation have on the heart?

    <p>Decreases heart effectiveness as a pump</p> Signup and view all the answers

    Which of the following correctly describes a unique function of the parasympathetic nervous system?

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

    How does parasympathetic stimulation affect bronchial muscles?

    <p>Causes broncho-constriction</p> Signup and view all the answers

    Which nerve is named the nervous erigenus and is related to sexual functions?

    <p>Pelvic nerve</p> Signup and view all the answers

    What is an indirect effect of parasympathetic stimulation on the coronary vessels?

    <p>Vasoconstriction due to less cardiac work</p> Signup and view all the answers

    Which of the following organs is solely supplied by the sympathetic nervous system?

    <p>Dilator pupillae muscle</p> Signup and view all the answers

    Which of the following is true regarding mucous secretion in the bronchial mucus glands due to parasympathetic stimulation?

    <p>Mucous secretion increases</p> Signup and view all the answers

    What occurs when the parasympathetic nervous system is activated in relation to the internal anal and urethral sphincters?

    <p>Relaxation of the internal sphincter</p> Signup and view all the answers

    Which property of the heart is NOT affected by parasympathetic stimulation?

    <p>Contraction of ventricles</p> Signup and view all the answers

    What is the primary cause of vasoconstriction in coronary vessels as indirect effect of parasympathetic stimulation?

    <p>Inhibition of cardiac work</p> Signup and view all the answers

    How does the sympathetic nervous system generally affect heart rate compared to the parasympathetic nervous system?

    <p>Sympathetic increases heart rate while parasympathetic decreases</p> Signup and view all the answers

    Which of the following glands is stimulated by the parasympathetic nervous system?

    <p>Glands of the stomach</p> Signup and view all the answers

    Which statement is true regarding the supply of most organs by the autonomic nervous system?

    <p>Most organs receive dual supply from both systems</p> Signup and view all the answers

    What is the primary role of the occulomotor nerve in the function of the parasympathetic nervous system?

    <p>Facilitates pupillary constriction and accommodation for near vision</p> Signup and view all the answers

    Which components are associated with the facial nerve in the parasympathetic nervous system?

    <p>Lacrimal gland and submandibular gland</p> Signup and view all the answers

    What is the origin of the greater superficial petrosal nerve in the brain?

    <p>Superior salivary nucleus</p> Signup and view all the answers

    Which statement accurately describes the composition of the salivary secretion from the submandibular gland?

    <p>It is large, watery, rich in electrolytes, and poor in enzymes.</p> Signup and view all the answers

    What type of fibers primarily supply the terminal ganglion associated with the pelvic component of the parasympathetic nervous system?

    <p>Parasympathetic fibers from sacral segments 2, 3, and 4</p> Signup and view all the answers

    Which cranial nerve is primarily responsible for mucous secretion in the nasal and pharyngeal regions?

    <p>Facial nerve</p> Signup and view all the answers

    Which nucleus is associated with the parasympathetic functions of the vagus nerve?

    <p>Dorsal motor nucleus of vagus</p> Signup and view all the answers

    What physiological effect does parasympathetic stimulation have on the ciliary muscle?

    <p>Stimulates contraction for accommodation to near vision</p> Signup and view all the answers

    What is the primary role of parasympathetic stimulation during near vision tasks?

    <p>To decrease pupil size and enhance lens power</p> Signup and view all the answers

    What effect does parasympathetic stimulation have on the heart?

    <p>Decreases the heart's effectiveness as a pump</p> Signup and view all the answers

    What is the indirect effect of parasympathetic stimulation on coronary vessels?

    <p>Vasoconstriction resulting from reduced cardiac work</p> Signup and view all the answers

    How does the parasympathetic nervous system affect bronchial mucus glands?

    <p>Increases mucus secretion</p> Signup and view all the answers

    During which type of vision is parasympathetic stimulation particularly important?

    <p>Near vision</p> Signup and view all the answers

    Which of the following best describes the vagus nerve's supply to the heart?

    <p>Supplies only the atria</p> Signup and view all the answers

    What is the effect of parasympathetic stimulation on bronchial muscle tone?

    <p>Induces bronchoconstriction</p> Signup and view all the answers

    What effect does the parasympathetic nervous system have on sphincter muscles?

    <p>Relaxation of both internal anal and urethral sphincters</p> Signup and view all the answers

    Which statement accurately describes a unique function of the parasympathetic nervous system?

    <p>Enhances secretion from digestive glands</p> Signup and view all the answers

    What is the role of the pelvic nerve in relation to the parasympathetic nervous system?

    <p>It is associated with erectile function and stimulation of secretion</p> Signup and view all the answers

    Which organs are solely supplied by the parasympathetic nervous system?

    <p>Constrictor pupillae muscle and upper esophagus</p> Signup and view all the answers

    How does the parasympathetic nervous system affect bile flow in the digestive process?

    <p>Stimulates increased bile flow and relaxation of the sphincter of Oddi</p> Signup and view all the answers

    What is the impact of parasympathetic stimulation on the micturition process?

    <p>Stimulates detrusor contraction and internal sphincter relaxation</p> Signup and view all the answers

    Which of the following describes a contrast between the sympathetic and parasympathetic nervous systems?

    <p>Sympathetic system elevates heart rate while parasympathetic decreases it</p> Signup and view all the answers

    What is the relationship between the autonomic nervous system and its dual supply to most organs?

    <p>One system usually promotes function while the other inhibits it</p> Signup and view all the answers

    Study Notes

    Parasympathetic Nervous System Functions

    • The parasympathetic nervous system (PSNS) is one of the two main divisions of the autonomic nervous system, responsible for regulating bodily functions that conserve energy and promote digestion.
    • It is composed of nerves originating from the brain stem and the sacral region of the spinal cord.
    • These nerves travel to various organs and tissues throughout the body, influencing several key functions.

    Parasympathetic Nerve Pathways

    • Oculomotor nerve (III):

      • Edinger-Westphal nucleus in the midbrain.
      • Relays to the ciliary ganglion.
      • Controls pupillary constriction (miosis) via the constrictor pupillae muscle and accommodation to near vision by controlling the ciliary muscle.

    • Facial nerve (VII):

      • Greater superficial petrosal nerve:
        • Originates from the superior salivary nucleus in the pons.
        • Relays to the sphenopalatine ganglion.
        • Responsible for lacrimal gland (tear) secretion and mucous membrane secretion in the nose, pharynx, and soft palate.
      • Chorda tympani nerve:
        • Originates from the superior salivary nucleus in the pons.
        • Relays to the submandibular ganglion.
        • Involved in true salivary secretion (large, watery saliva rich in electrolytes) from the sublingual and submandibular glands and mucous membrane secretion in the anterior 2/3 of the tongue.

    • Glossopharyngeal nerve (IX):

      • Originates from the inferior salivary nucleus in the medulla.
      • Relays to the otic ganglion.
      • Controls true salivary secretion from the parotid gland and mucous membrane secretion in the posterior 1/3 of the tongue.

    • Vagus nerve (X):

      • Originates from the dorsal motor nucleus of the vagus in the medulla.
      • Relays to terminal ganglia.
      • Controls various functions in the heart, lungs, gastrointestinal system, and other visceral organs.

    • Pelvic nerve:

      • Originates from the sacral spinal segments 2, 3, and 4.
      • Relays to terminal ganglia.
      • Controls functions related to urination, defecation, and sexual arousal.

    Parasympathetic Effects on Specific Organs

    • Eye:

      • Pupillary constriction (miosis) to reduce light entering the eye, essential for near vision.
      • Accommodation to near vision by increasing the lens power to focus on nearby objects.

    • Heart:

      • Decreases heart rate and contractility, reducing the effectiveness of the heart as a pump.
      • Causes vasodilation of coronary vessels directly, but indirectly promotes vasoconstriction due to reduced cardiac workload and metabolite accumulation.

    • Lungs:

      • Bronchoconstriction by stimulating bronchial muscles.
      • Increase mucous secretion by stimulating bronchial glands.

    • Gastrointestinal System:

      • Increases bile flow and relaxes the sphincter of Oddi, facilitating bile release into the duodenum.
      • Stimulates secretion from the pancreas, gastric glands, and Brunner's glands in the duodenum.
      • Increases contraction of gastrointestinal walls and relaxes sphincters, promoting digestion and movement of food through the gut.
      • Causes vasodilation of gastrointestinal blood vessels.

    • Urinary System:

      • Increases contraction of the bladder wall and relaxes the internal urethral sphincter, promoting urination.

    • Reproductive System:

      • Causes vasodilation leading to erection of the penis and clitoris.
      • Stimulates glandular secretions.

    Other Important Points:

    • The parasympathetic nervous system generally promotes energy conservation, digestion, and rest.
    • The external anal and urethral sphincters are controlled by somatic spinal pudendal nerves, allowing voluntary control of urination and defecation.
    • The majority of organs receive dual innervation from both the sympathetic and parasympathetic nervous systems, allowing fine-tuned control of organ function.
    • Certain organs are exclusively innervated by either the sympathetic or parasympathetic nervous system.
    • The relationship between the sympathetic and parasympathetic nervous systems is often antagonistic, with one system counteracting the effects of the other.

    Examples of Antagonistic Effects:

    • Sympathetic nervous system increases heart rate, while the parasympathetic nervous system decreases it.
    • Sympathetic nervous system promotes pupillary dilation, while the parasympathetic nervous system promotes constriction.

    Parasympathetic Nervous System Functions

    • The parasympathetic nervous system is responsible for "rest and digest" functions.
    • It helps relax the body and conserve energy.
    • It acts primarily through the vagus nerve and pelvic nerves.
    • It helps control pupillary constriction (miosis) and accommodation to near vision.
    • Oculomotor nerve (cranial nerve 3): controls constrictor pupillae muscle and ciliary muscle for near vision.
      • It originates from the Edinger-Westphal nucleus in the midbrain.
    • Facial nerve (cranial nerve 7): stimulates lacrimal glands, mucous membranes of the nose, pharynx, and anterior 1/3 of tongue, and salivary glands (sublingual and submandibular).
      • Greater superficial petrosal nerve: responsible for lacrimal and mucous glands.
      • Chorda tympani: stimulates sublingual and submandibular salivary glands.
    • Glossopharyngeal nerve (cranial nerve 9): stimulates parotid salivary gland.
      • Originates from the inferior salivary nucleus in the medulla.
    • Vagus nerve (cranial nerve 10): controls heart, lungs, digestive system, and some glands.
      • Originates from the dorsal motor nucleus of vagus in the medulla.
    • Pelvic nerves (S2-S4): control lower digestive system, urinary bladder, and reproductive organs.

    Cardiac function

    • Decreases heart rate, rhythmicity, excitability, conductivity, and contractility.
    • Vagus nerve only supplies the atria (not ventricles).
    • Coronary vasodilatation via direct effect.
    • Indirect vasoconstriction due to inhibition of cardiac work and less metabolites accumulation.

    Respiratory function

    • Bronchoconstriction by stimulating bronchial muscles.
    • Increases mucus secretion by stimulating bronchial glands.

    Digestive function

    • Increases bile flow and relaxes sphincter of Oddi for bile emptying.
    • Stimulates pancreatic secretion.
    • Stimulates gastric glands and Brunner's glands in the duodenum.
    • Contraction of digestive tract walls and relaxation of sphincters.
    • Vasodilatation and stimulation of emptying of the digestive tract.

    Urinary/Reproductive function

    • Contraction of bladder walls and relaxation of internal urethral sphincter facilitating micturition.
    • Contraction of rectal walls and relaxation of internal anal sphincter for defecation.
    • Vasodilatation and stimulation of glands leading to erection of the penis and clitoris.

    Other functions

    • External anal and urethral sphincters are voluntary muscles controlled by the somatic spinal pudendal nerve.
    • Most organs are dual innervated by sympathetic and parasympathetic nervous systems.
    • Some organs are only innervated by one division of the autonomic nervous system:
      • Sympathetic only: dilator pupillae muscle, Muller's muscle, upper esophagus, cutaneous effectors, ventricles of the heart, spleen, adrenal medulla.
      • Parasympathetic only: constrictor pupillae muscle, glands of the stomach.
    • Sympathetic and parasympathetic nervous systems act antagonistically in many cases:
      • For example, heart rate increased by sympathetic NS, decreased by parasympathetic NS.

    Pelvic nerve

    • Also known as the nervus erigenus.

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