المحاضرة السادسة فسيو (بعد التعديل)
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Questions and Answers

What is the primary function of the sympathetic nervous system in relation to the pupil?

  • Regulating tear production
  • Constriction of the pupil
  • Elevation of the upper eyelid
  • Dilating the pupil (correct)
  • Which type of secretion is primarily associated with sympathetic control in salivary glands?

  • Viscous and rich in electrolytes
  • Viscous and concentrated with enzymes (correct)
  • Aqueous and poor in enzymes
  • Thin and rich in water
  • What is the primary relay station for sympathetic nervous system fibers to the head and neck?

  • Superior cervical ganglia (correct)
  • Lateral horn of the lumbar spinal cord
  • Inferior cervical ganglia
  • Cervical spinal cord
  • Which sign is characteristic of disruption in sympathetic innervation to the head and neck?

    <p>Drooping of the upper eyelid</p> Signup and view all the answers

    The sympathetic nervous system leads to the contraction of which muscle to cause the elevation of the upper eyelid?

    <p>Superior tarsal muscle</p> Signup and view all the answers

    What effect does sympathetic innervation have on blood vessels in the skin?

    <p>Mild vasoconstriction</p> Signup and view all the answers

    What anatomical structures are affected by lesions in T1 and T2 segments of the spinal cord?

    <p>Sympathetic pathways to the head and neck</p> Signup and view all the answers

    Which of the following is NOT a function of the sympathetic nervous system concerning the eye?

    <p>Constriction of pupils</p> Signup and view all the answers

    Which of the following is a result of sympathetic innervation in the head and neck region?

    <p>Contraction of the dilator pupillae muscle</p> Signup and view all the answers

    What indicates a possible lesion in the sympathetic nerves to the head and neck?

    <p>Drooping of the upper eyelids</p> Signup and view all the answers

    Which muscle's contraction is primarily responsible for exophthalmos due to sympathetic innervation?

    <p>Muller's muscle</p> Signup and view all the answers

    Which of the following effects does sympathetic nervous system activation NOT produce in the salivary glands?

    <p>Rich secretion of electrolytes</p> Signup and view all the answers

    What is the primary ganglia involved in relaying sympathetic signals to the head and neck?

    <p>Superior cervical ganglia</p> Signup and view all the answers

    What mechanism leads to accommodation for far vision under sympathetic activation?

    <p>Relaxation of the ciliary muscle</p> Signup and view all the answers

    Which best describes the effect of sympathetic nervous activity on blood vessels in the skin?

    <p>Mainly vasoconstriction</p> Signup and view all the answers

    Which symptom does NOT result from sympathetic nervous system disruption in the head and neck?

    <p>Secretions from lacrimal glands</p> Signup and view all the answers

    Study Notes

    Sympathetic Innervation to Head & Neck

    • Origin: Lateral horn cells of the first and second thoracic segments of the spinal cord
    • Relay (Ganglia): Superior Cervical Ganglia (SCG)

    Functions

    • Eye
      • Mydriasis (pupil dilatation): Contraction of the dilator pupillae muscle (radial muscle)
      • Elevation of upper eyelid: Contraction of the superior tarsal muscle, widening the palpebral fissure
      • Exophthalmos: Contraction of Muller's muscle (behind the eyeball)
      • Accommodate far vision: Relaxation of the ciliary muscle, decreasing the convexity of the lens
      • Vasoconstriction (VC) and trophic secretion of lacrimal glands
    • Salivary Glands
      • Vasoconstriction (VC) of salivary gland blood vessels
      • Trophic secretions:
        • Little
        • Viscous and concentrated
        • Poor in water and electrolytes
        • Rich in enzymes
      • Contraction of myoepithelial cells: Squeezing of salivary secretion to the outside.
    • Skin
      • Vasoconstriction (VC) or Vasodilation (VD) of skin blood vessels, but mainly VC
      • Erection of Hair due to contraction of the pilo-erector muscle
      • Sweat secretion
    • Cerebral Vessels: Mild vasoconstriction (VC)

    Horner's Syndrome

    • Definition: A group of signs resulting from interruption of the sympathetic nerve supply to the head and neck.
    • Location: Occurs on the same side of the lesion.
    • Causes:
      • Lesion in T1 and T2 segments
      • Lesion in the Superior Cervical Ganglion
    • Signs:
      • Ptosis: Dropping of the upper eyelids due to paralysis of the superior tarsal muscles.
      • Miosis: Constriction of the pupils due to paralysis of the dilator pupillae muscle.

    Sympathetic Nervous System to Head and Neck

    • Origin: Lateral horn cells of the first and second thoracic segments of the spinal cord.
    • Relay (Ganglia): Superior cervical ganglia (SCG).

    Functions

    • Eye
      • Mydriasis (pupil dilatation): Contraction of the dilator pupillae muscle (radial muscle).
      • Elevation of upper eyelid: Contraction of the superior tarsal muscle, widening the palpebral fissure.
      • Exophthalmos: Contraction of Muller's muscle (behind the eyeball).
      • Accommodation for far vision: Relaxation of the ciliary muscle, decreasing the convexity of the lens.
      • Vasoconstriction (VC) and trophic secretion of lacrimal glands.
    • Salivary Glands
      • VC of salivary gland blood vessels.
      • Trophic secretions: Little, viscous, concentrated secretion, poor in water and electrolytes, rich in enzymes.
      • Contraction of myoepithelial cells: Squeezing of salivary secretion to the outside.
    • Skin
      • VC or VD of skin blood vessels, but mainly VC.
      • Erection of hair: Contraction of pilo-erector muscle.
      • Sweat secretion.
    • Cerebral vessels: Mild vasoconstriction

    Horner Syndrome

    • Definition: A group of signs resulting from interruption of sympathetic innervation to the head and neck.
    • Occurs on the same side as the lesion.
    • Causes:
      • Lesion in T1 and T2 spinal segments.
      • Lesion in the Superior cervical ganglia.
    • Signs:
      • Ptosis: Dropping of upper eyelids due to paralysis of superior tarsal muscles.
      • Miosis: Constriction of pupils due to paralysis of the dilator pupillae muscle.

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