Autonomics of the head Flashcards

1
Q

The following structures of the head require autonomic innervation

A
  1. Blood vessels, sweat glands, arrector pili
  2. Mucous-secreting glands of head
  3. Lacrimal gland
  4. Parotid gland
  5. Submandibular gland
  6. Sublingual gland
  7. Intraocular eye muscles (sphincter and dilator pupillae; ciliary muscle)
  8. Superior tarsal muscle of eye
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2
Q

general sympathetic innervation

A

B. Sympathetic innervation arises from the upper thoracic spinal cord and ascends the sympathetic chain to the superior cervical ganglion. From here, postganglionic fibers travel with the external carotid artery (external carotid nerve) to get to superficial structures and the internal carotid artery (internal carotid nerve) to get to deeper structures of the head.

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3
Q

general parasympathetic innervationa.

A

Parasympathetic innervation arises from 4 cranial nerves and 4 cranial ganglia.

  1. Cranial Nerves
    a. Oculomotor nerve
    b. Facial nerve
    c. Glossopharyngeal nerve
    d. Vagus nerve
4 ganglia:
Ciliary
Pterygopalatine
Submandibular
Otic
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4
Q

Ciliary ganglion

A
  1. Location – orbit; between optic nerve and lateral rectus.
  2. Sensory root – from nasociliary branch of V1
  3. GVE-P root – from oculomotor nerve
  4. GVE-S root – from internal carotid nerve (via cavernous branch)
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5
Q

Pterygopalatine ganglion

A
  1. Location – pterygopalatine fossa
  2. Sensory root – from pterygopalatine branches of V2
  3. GVE-P root – from greater petrosal nerve of pterygoid canal (CN VII).
  4. GVE-S root – from deep petrosal nerve of nerve of pterygoid canal.
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6
Q

Submandibular ganglion

A
  1. Location – oral cavity
  2. Sensory root – from lingual nerve of V3
  3. GVE-P root – from chorda tympani nerve of CN VII.
  4. GVE-S root – from external carotid nerve.
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7
Q

Otic ganglion

A
  1. Location – infratemporal fossa
  2. Sensory root – from V3
  3. GVE-P root – from lesser petrosal branch of CN IX.
  4. GVE-S root – from external carotid nerve.
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8
Q

The trigeminal nerve is associated with all 4 parasympathetic ganglia of the head.

A

CN V does not carry parasympathetic fibers of its own, but suspends each ganglion and distributes parasympathetic, sympathetic, and sensory fibers to their target structures.

a. V1 suspends the ciliary ganglion and distributes fibers to the eye.
b. V2 suspends the pterygopalatine ganglion and distributes fibers to the lacrimal gland, nasal cavities, paranasal sinuses, and palate.
c. V3 suspends the submandibular ganglion and distributes fibers to the submandibular and sublingual glands.
d. V3 suspends the otic ganglion and distributes fibers to the parotid gland.

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9
Q

II. Parasympathetic innervation of head

A. Oculomotor nerve (CN III)

A
  1. Pathway of innevation to intraocular muscles.
    a. Preganglionic parasympathetic cell bodies – Edinger Westphal nucleus
    b. Preganglionic parasympathetic fibers – CN III (inferior division)
    c. Postganglionic parasympathetic cell bodies – ciliary ganglion
    d. Postganglionic parasympathetic fibers – short ciliary branches of V1
  2. Distribution and Function
    a. Sphincter pupillae muscle – miosis (constriction of pupil)
    b. Ciliary muscle – accommodation
  3. Dysfunction
    a. Sphincter pupillae muscle – loss of pupillary light response; dilated pupil
    b. Ciliary muscle – loss of accommodation
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10
Q

Parasympathetics: Facial nerve – greater petrosal branch

A
  1. Pathway for innervation to mucous-secreting glands of head and lacrimal gland.
    a. Preganglionic parasympathetic cell bodies – salivatory nucleus
    b. Preganglionic parasympathetic fibers – CN VII (greater petrosal n)
    c. Postganglionic parasympathetic cell bodies – pterygopalatine ganglion
    d. Postganglionic parasympathetic fibers – various branches of V2 to mucous-secreting glands of nasal cavity, paranasal sinuses, and palate.
    e. Postganglionic parasympathetic fibers – zygomatic branch of V2 and lacrimal branch of V1 to lacrimal gland.
  2. Distribution and Function
    a. Lacrimal gland – increases lacrimation
    b. Mucous-secreting glands – increase mucous secretion to lubricate mucosa.
  3. Dysfunction
    a. Lacrimal gland – dry, red eye due to deceased lacrimal fluid production
    b. Mucous-secreting glands – dry, irritated mucous-membranes
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11
Q

Parasympathetics: C. Facial nerve – chorda tympani branch

A
  1. Pathway for innervation to submandibular and sublingual glands.
    a. Preganglionic parasympathetic cell bodies – salivatory nucleus
    b. Preganglionic parasympathetic fibers – CN VII (chorda tympani n)
    c. Postganglionic parasympathetic cell bodies – submandibular ganglion
    d. Postganglionic parasympathetic fibers – lingual branch of V3 to submandibular and sublingual glands.
  2. Distribution and Function
    a. Submandibular gland – increases gland secretion
    b. Sublingual gland – increases gland secretion
    c. NOTE: also carries SVA (taste to anterior 2/3 of tongue)
  3. Dysfunction
    a. Submandibular gland - xerostomia (dry mouth) due to decreased salivation.
    b. Sublingual gland - xerostomia (dry mouth) due to decreased salivation.
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12
Q

Parasympathetics: glossopharyngeal nerve

A
  1. Pathway for innervation to parotid gland.
    a. Preganglionic parasympathetic cell bodies – salivatory nucleus
    b. Preganglionic parasympathetic fibers – CN IX (lesser petrosal n)
    c. Postganglionic parasympathetic cell bodies – otic ganglion
    d. Postganglionic parasympathetic fibers – auriculotemporal branch of V3 to parotid sublingual gland.
  2. Distribution and Function
    a. Parotid gland – increases gland secretion
  3. Dysfunction
    a. Parotid gland - xerostomia (dry mouth) due to decreased salivation.
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13
Q

Parasympathetics: Vagus

A
  1. This is the pathway for innervation of smooth muscle, glands, blood vessels of the neck, thorax, and most of the abdomen.
  2. Specific named branches involved: Pharyngeal branches, laryngeal branches, cardiac and pulmonary branches, visceral branches to gut.
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14
Q

Sympathetic innervation of head

A

A. Preganglionic sympathetic neurons

  1. Cell bodies for the entire head originate in the IMLCC at T1-T4
  2. Preganglionic fibers enter sympathetic chain via white rami and ascend to the superior cervical ganglion (SCG).

B. Postganglionic sympathetic neurons
1. Cell bodies for the entire head originate in the SCG.
2. Postganglionic fibers follow two primary routes to the head:
Internal carotidd nerve
Deep petrosal nerve

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15
Q

Pathway of sympathetics: internal carotid

A

a. Internal carotid nerve
1. Distribute via branches of the internal carotid artery to deep structures of head.
2. Provides the following specific nerves:
a. Cavernous sinus nerve
1. Follows internal carotid artery through the cavernous sinus.
2. Forms sympathetic root to ciliary ganglion.
3. Provides innervation to superior tarsal and dilator pupillae muscles.
4. Superior tarsal muscle
a. Assists (CN III) with elevation of the upper eyelid.
b. Dysfunction – ptosis
5. Dilator pupillae muscle
a. Dilates pupil to allow more light to enter eye.
b. Dysfunction – constricted pupil; loss of pupillary dilation

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16
Q

Pathways of sympathetics: deep petrosal nerve

A
  1. Merges with greater petrosal nerve to form n of pterygoid canal.
  2. Forms sympathetic root to pterygopalatine ganglion.
  3. Provides innervation to the glands and blood vessels of the nasal cavity, paranasal sinuses, palate, and lacrimal gland.
17
Q

what sympathetic innervation to glands does

A

Sympathetic innervation to glands (mucous-secreting; salivary; lacrimal) (exception – sweat glands) is complicated. In general, sympathetic innervation modifies the composition of secretion; making it more watery in most cases. Sympathetic innervation is typically less dense to these structures than parasympathetic. Thus, loss of sympathetic innervation to these glands will typically not cause any noticeable symptoms.

18
Q

External carotid nerve

A
  1. These fibers will distribute via branches of the external carotid artery to the superficial structures of the head.
  2. Provides sympathetic innervation to:
    a. All salivary glands (parotid, submandibular, sublingual)
    b. Sweat glands, blood vessels of face
  3. Sweat glands
    a. Sympathetic innervation stimulates sweating
    b. Dysfunction – loss of facial sweating (anhidrosis)
19
Q

Most common causes of horner syndrome in adults: central

A

Hypothalamus (stroke, tumor)

brainstem (stroke– lateral medullary infarction, demyelination, tumor)

20
Q

Most common causes of horner syndrome in adults: preganglionic

A

cervical spine disease
brachial plexus injury

pulmonary apical lesions (apical lung tumor, mediastinal tumors, cervical rib, trauma, iatrogenic- jugular cannulation, chest tube, thoracic surgery)
subclavian artery anerysm

21
Q

Most common causes of horner syndrome in adults: postganglionic

A

superior cervical ganglion (trauma, jugular venous ectasia, iatrogenic - surgical neck dissection)

internal carotid artery (dissection, aneurysm, trauma, arteritis, tumor)

22
Q

CLINICAL CORRELATION – Horner’s Syndrome

A
  1. Loss of sympathetic innervation to head.
  2. Causes: lesion within brain affecting descending sympathetic pathway from hypothalamus (dorsal longitudinal fasciculus; stroke/tumor/lateral medullary syndrome); lesion of sympathetic chain in root of neck (Pancoast tumor); lesion of superior cervical ganglion.
  3. Classic triad of presentation of Horner’s Syndrome:
    a. Miosis – constriction of pupil due to loss of dilator pupillae muscle
    b. Ptosis – drooping of eyelid due to loss of superior tarsal muscle
    c. Anhydrosis – loss of sweating due to loss of innervation to sweat glands.
  4. Less common features:
    a. Enophthalamos – (?)
    b. Lack of facial flushing on affected side (most often noted by increased flushing in response to heat on contralateral side). Due to loss of sympathetic innervation to blood vessels. Note: Sympathetic innervation to many blood vessels of cheeks is epinephrine via beta adrenergic receptors; thus causing vasodilation (blushing).
23
Q

IV. Summary of Autonomic Innervation to Intraocular Eye Muscles : parasympathetics

A

A. Parasympathetics to sphincter pupillae and ciliary muscle

  1. Preganglionic cells bodies – Edinger-Westphal nucleus
  2. Preganglionic – oculomotor nerve
  3. Postganglionic cells bodies – ciliary ganglion.
  4. Postganglionic fibers distribute via the short ciliary nn to the sphincter pupillae muscle and ciliary muscle.
  5. Function – pupillary constriction; accommodation
  6. Dysfunction – pupil dilated; loss of pupillary light reflex; loss of accommodation
24
Q

Sympathetics for dilator pupillae and superior tarsal muscle

A
  1. Preganglionic cell bodies – IMLCC at T1-T4
  2. Preganglionic fibers ascend sympathetic chain
  3. Postganglionic cell bodies – superior cervical sympathetic ganglion
  4. Postganglionic fibers – internal carotid nerve (cavernous branch)
  5. Postganglionic fibers distribute via long and short ciliary nn to the dilator pupillae muscle and superior tarsal muscle (of LPS).
  6. Function – pupillary dilation; assist with elevation of upper eyelid
  7. Dysfunction – pupil constricted; ptosis of upper eyelid
25
Q

Summary of Autonomic Innervation to the Lacrimal Gland: parasympathetics

A
  1. Preganglionic cell bodies – salivatory nucleus
  2. Preganglionic fibers – CN VII (greater petrosal branch)
  3. Postganglionic cell bodies – pterygopalatine ganglia.
  4. Postganglionic fibers distribute with the zygomatic (V2) and lacrimal (V1) nerves.
  5. Function – increase lacrimal gland secretion
  6. Dysfunction – dry, irritated eye due to decreased lacrimal gland secretion
26
Q

Summary of Autonomic Innervation to the Lacrimal Gland: sympathetics

A
  1. Preganglionic cell bodies – IMLCC at T1-T4
  2. Preganglionic fibers ascend sympathetic chain
  3. Postganglionic cells bodies – superior cervical sympathetic ganglia
  4. Postganglionic fibers – internal carotid nerve (deep petrosal branch)
  5. Postganglionic fibers distribute with the zygomatic (V2) and lacrimal (V1) nerves.
  6. Function – vasomotor; modify lacrimal secretion
  7. Dysfunction – minimal effect
27
Q

Summary of Autonomic Innervation to Mucous-secreting Glands of Head : parasympathetics

A
  1. Preganglionic cell bodies – salivatory nucleus
  2. Preganglionic fibers – CN VII (via greater petrosal n)
  3. Postganglionic cell bodies – pterygopalatine ganglion
  4. Postganglionic fibers distribute via multiple branches of V2
  5. Function – secretomotor; increase mucous secretion
  6. Dysfunction – dry mucus membranes
28
Q

Summary of Autonomic Innervation to Mucous-secreting Glands of Head

A
  1. Preganglionic cell bodies – IMLCC at T1-T4
  2. Preganglionic fibers ascend sympathetic chain
  3. Postganglionic cells bodies – superior cervical sympathetic ganglia
  4. Postganglionic fibers – internal carotid nerve (via deep petrosal branch)
  5. Function – vasomotor; modify secretion (increase water secretion)
  6. Dysfunction – minimal
29
Q

VII. Summary of Autonomic Innervation to the Submandibular and Sublingual Glands : parasympathetic

A
  1. Preganglionic cell bodies – salivatory nucleus
  2. Preganglionic fibers – CN VII (via chorda tympani)
  3. Postganglionic cell bodies – submandibular ganglion
  4. Postganglionic fibers distribute with the lingual n (V3)
  5. Function – secretomotor; increase salivation
  6. Dysfunction – dry mouth (xerostomia)
30
Q

VII. Summary of Autonomic Innervation to the Submandibular and Sublingual Glands : sympathetic

A
  1. Preganglionic cell bodies – IMLCC at T1-T4
  2. Preganglionic fibers ascend sympathetic chain
  3. Postganglionic cells bodies – superior cervical sympathetic ganglia
  4. Postganglionic fibers – external carotid nerve
  5. Function – vasomotor; modify secretion (increase water secretion)
  6. Dysfunction – minimal
31
Q

Summary of Autonomic Innervation to the Parotid Gland : parasympathetics

A
  1. Preganglionic cell bodies – salivatory nucleus
  2. Preganglionic fibers – CN IX (via tympanic and lesser petrosal pathway)
  3. Postganglionic cell bodies – otic ganglion
  4. Postganglionic fibers distribute with the auriculotemporal n (V3)
  5. Function – secretomotor; increase salivation
  6. Dysfunction – dry mouth (xerostomia)
32
Q

sympathetics to the parotid gland

A
  1. Preganglionic cell bodies – IMLCC at T1-T4
  2. Preganglionic fibers ascend sympathetic chain
  3. Postganglionic cells bodies – superior cervical sympathetic ganglia
  4. Postganglionic fibers – external carotid nerve
  5. Function – vasomotor; modify parotid secretion (increase water secretion)
  6. Dysfunction – minimal