Podcast
Questions and Answers
What is the primary function of the sympathetic nervous system in relation to the pupil?
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?
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?
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?
Which sign is characteristic of disruption in sympathetic innervation to the head and neck?
The sympathetic nervous system leads to the contraction of which muscle to cause the elevation of the upper eyelid?
The sympathetic nervous system leads to the contraction of which muscle to cause the elevation of the upper eyelid?
What effect does sympathetic innervation have on blood vessels in the skin?
What effect does sympathetic innervation have on blood vessels in the skin?
What anatomical structures are affected by lesions in T1 and T2 segments of the spinal cord?
What anatomical structures are affected by lesions in T1 and T2 segments of the spinal cord?
Which of the following is NOT a function of the sympathetic nervous system concerning the eye?
Which of the following is NOT a function of the sympathetic nervous system concerning the eye?
Which of the following is a result of sympathetic innervation in the head and neck region?
Which of the following is a result of sympathetic innervation in the head and neck region?
What indicates a possible lesion in the sympathetic nerves to the head and neck?
What indicates a possible lesion in the sympathetic nerves to the head and neck?
Which muscle's contraction is primarily responsible for exophthalmos due to sympathetic innervation?
Which muscle's contraction is primarily responsible for exophthalmos due to sympathetic innervation?
Which of the following effects does sympathetic nervous system activation NOT produce in the salivary glands?
Which of the following effects does sympathetic nervous system activation NOT produce in the salivary glands?
What is the primary ganglia involved in relaying sympathetic signals to the head and neck?
What is the primary ganglia involved in relaying sympathetic signals to the head and neck?
What mechanism leads to accommodation for far vision under sympathetic activation?
What mechanism leads to accommodation for far vision under sympathetic activation?
Which best describes the effect of sympathetic nervous activity on blood vessels in the skin?
Which best describes the effect of sympathetic nervous activity on blood vessels in the skin?
Which symptom does NOT result from sympathetic nervous system disruption in the head and neck?
Which symptom does NOT result from sympathetic nervous system disruption in the head and neck?
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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