PNS 5 Flashcards

1
Q

Where does CN VII, the Facial Nerve, arise from?

A

The BRAINSTEM at the Inferior Pontine Sulcus, in line with the Postolivary Sulcus of the Medulla.

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2
Q

What are the 4 functional components (Nerve fiber types) that CN VII carries?

A
  1. SVE
  2. GVE
  3. SVA
  4. GSA
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3
Q

What CN lies next to CN VIII in the Cerebellopontine Angle (the angle between the lateral pons and the inferior aspect of the cerebellum)?

A

CN VII

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4
Q

CN VII consists of 2 Primary Roots. What are they and what Fiber Type(s) does each carry?

A
  1. The Larger division, or MOTOR ROOT, carries
    - Branchial Motor Fibers (SVE).
  2. The Smaller division, or NERVUS INTERMEDIUS, carries
    - Preganglionic Parasympathetics (GVE)
    - Special Sensory Fibers (SVA - Taste)
    - General Sensory Fibers (GSA)
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5
Q

CN VII fibers either arise from (Efferents) or project to (Afferents) a number of PONTINE Nuclei. Give the Nuclei associated w/ each of the following fibers

  1. Branchial Efferent (SVE) fibers
  2. GVE fibers
  3. SVA (taste) fibers
  4. GSA
A
  1. Facial (MOTOR) Nucleus
  2. SALIVATORY Nucleus
  3. Nucleus of the SOLITARY TRACT
  4. Spinal Nucleus of CN V
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6
Q

From what Ganglion do the Afferents (SVA & GVA) of CN VII arise from primary cell bodies in? Note: Ganglion is found w/in the temporal bone

A

GENICULATE GANGLION

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7
Q

Through what hole does CN VII enter the temporal bone through? What other CNs pass through this opening?

A

INTERNAL ACOUSTIC MEATUS

-Along w/ the COCHLEAR & VESTIBULAR Nerves of CN VIII

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8
Q

The Geniculate Ganglion, which gives rise to the afferent facial nerves, is located in what Canal?

A

It is located at a bend (hence geniculate) in the FACIAL CANAL.

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9
Q

CN VII branches extensively in what Canal that is located in the petrous portion of the temporal bone?

A

The FACIAL CANAL

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10
Q

What are the 3 motor branches of CN VII to leave while in the Facial Canal? List in order of departure

A
  1. GREATER PETROSAL Nerve
  2. Nerve to STAPEDIUS
  3. CHORDA TYMPANI
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11
Q

The Greater Petrosal nerve leaves the facial canal at the level of the Geniculum through what opening? The greater petrosal nerve then enters the middle cranial fossa and eventually exits the skull through what opening?

A
  1. The Greater Petrosal Nerve leaves the facial canal through the HIATUS OF THE GREATER PETROSAL NERVE into the Middle cranial fossa.
  2. The Greater Petrosal Nerve Leaves the skull through the FORAMEN LACERUM.
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12
Q

After exiting the skull the Greater Petrosal Nerve passes through the Pterygoid Canal to reach what Ganglion?

A

The PTERYGOPALATINE GANGLION

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13
Q

The STAPEDIAL Nerve is second to branch from CN VII. What muscle is it responsible for innervating?

A

The STAPEDIUS MUSCLE in the Middle Ear Cavity.

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14
Q

Chorda Tympani is the last branch to leave CN VII w/in the facial nerve. It courses along the lateral wall of the Tympanic cavity until leaving the cranium how? This complex course leaves Chorda Tympani vulnerable to what?

A

Chorda Tympani exits the cranium through the ITER CHORDAE ANTERIUS at the Medial End of the PETROTYMPANIC FISSURE.
-Chorda Tympani is vulnerable to Middle Ear Infections and the swelling that results

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15
Q

After exiting the Iter Chordae Anterius from the petrotympanic fissure where does Chorda Tympani end up?

A

INFRATEMPORAL FOSSA

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16
Q

Through what opening does the Trunk of the FACIAL NERVE exit the skull?

A

STYLOMASTOID FORAMEN

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17
Q

Fibers in the trunk of the facial nerve are primarily concerned with innervating what group of muscles?

A

MUSCLES OF FACIAL EXPRESSION

Note: Also Stylohyoid and Posterior Digastric Muscles

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18
Q

Give a short description of the 5 distinct segments of CN VII w/in the Facial Canal

  1. LABYRINTHE
  2. EXTERNAL GENU
  3. TYMPANIC
  4. MASTOID
  5. TRUNK
A
  1. Labyrinth: Enters facial canal and passes above the labyrinth housing the Vestibular System
  2. Ext. Genu: Includes the Geniculate Ganglion
  3. Tympanic: Travels posteriorly & laterally along the medial wall of the middle ear cavity
  4. Mastoid: Gives rise to the nerve to stapedius and Chorda Tympani
  5. Trunk: Exits the facial canal
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19
Q

SVE fibers (Branchial Motor) of CN VII innervate second arch derivatives, which can be summarized into what 3 categories?

A
  1. Muscles of facial expression
  2. Stylohyoid & Posterior Digastric Muscles
  3. Stapedius Muscle
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20
Q

Most SVE fibers in the TRUNK of CN VII ramify within what plexus? What is the exception?

A

PAROTID PLEXUS

-The POSTERIOR AURICULAR Nerve brings some SVE fibers to more Posterior muscles of facial expression

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21
Q

Where is the Parotid Plexus located?

A

PAROTID Gland

22
Q

What is a pneumonic to help remember the branches of the CN VII trunk? What are they?

A

(PAinfully) Two Zebras Bit My Cock

  • Posterior Auricular (Note: doesn’t ramify in parotid gland)
  • Temporal
  • Zygomatic
  • Buccal
  • Marginal mandibular
  • Cervical
23
Q

What facial contortions would you ask a patient to perform to test each of the 5 CN VII branches from the parotid plexus?

A
  1. Temporal: Raise eyebrows
  2. Zygomatic: Shut eyes tightly
  3. Buccal: Bare upper teeth or whistle
  4. Marginal Mandibular: Bare lower teeth
  5. Cervical: Flare skin of the neck by tensing Platysma
24
Q

What is a danger faced for CN VII branches that pass through the Parotid Gland?

A

Tumors of the Parotid Gland may compress or destroy facial nerve fibers leading to partial facial paralysis. Cancer may also follow facial nerve back into cranial cavity! Very Bad.

25
Q

After leaving the Geniculate Ganglion, the GREATER PETROSAL NERVE, of CN VII, travels to what other Ganglion?

A

PTERYGOPALATINE GANGLION

26
Q

The Greater Petrosal Nerve of CN VII carries what fiber type? Give 3 descriptive terms.

A

GVE fibers - Parasympathetics - SECRETOMOTOR Fibers.

27
Q

The greater petrosal nerve innervates what? 4 things

A
  1. LACRIMAL GLAND
  2. NASAL MUCOSA
  3. PARANASAL MUCOSA
  4. PALATINE GLANDS
28
Q

What fiber type does Chorda Tympani (branch of CN VII) convey?

A

GVE - parasympathetic - Secretomotor Fibers

29
Q

After leaving the Geniculate Ganglion what ganglion do the secretomotor fibers of Chorda Tympani synapse in next? What do the fibers that synapsed in this ganglion innervate?

A

SUBMANDIBULAR GLAND.
-After leaving the submandibular gland these postganglionic, parasympathetic, secretomotor fibers innervate SUBMANDIBULAR & SUBLINGUAL SALIVARY GLANDS.

30
Q

Entering the Pterygoid Canal, the Greater Petrosal Nerve joins with the Deep Petrosal Nerve to form what nerve?

A

The NERVE OF THE PTERYGOID CANAL or VIDIAN NERVE.

31
Q

What are the two fiber types of the Nerve of the Pterygoid Canal (Vidian)? What nerve contributed each fiber type?

A

The Nerve of the Pterygoid Canal carries GVE parasympathetic nerves from the Greater Petrosal and Postganglionic Sympathetics from the Deep Petrosal Nerve.

32
Q

The Lacrimal gland is innervated by what?

A

The lacrimal gland is innervated by the Zygomatic branch of V2 and the postganglionic autonomics (symp & parasymp) from the Pterygopalatine Ganglion.

33
Q

What is the Nasal Mucosa innervated by?

A
  1. Postganglionic Autonomics from the Pterygopalatine Ganglion, which accompany…
  2. Posterior Lateral Nasal & Nasopalatine branches of V2 (Nasal branches of the maxillary nerve)
34
Q

What are the Palatine Glands innervated by?

A
  1. Postganglionic Autonomics from the Pterygopalatine Ganglion
  2. Greater & Lesser Palatine branches of V2
35
Q

What three glandular structures do the POSTGANGLIONIC AUTONOMICS from the PTERIGOPALATINE GANGLION innervate as they accompany branches of V2?

A
  1. LACRIMAL GLANDS
  2. NASAL MUCOSA
  3. PALATINE GLANDS
36
Q
  1. What two nerves feed into the Vidian Nerve?
  2. What fiber type does each carry?
  3. From there what Ganglion does the Vidian Nerve travel to?
  4. What fiber type synapses there?
A

1 & 2. Greater Petrosal Nerve (GVE - parasympathetics) and the Deep Petrosal Nerve (GVE - Sympathetics) combine in the Pterygopalatine Fossa to form the Vidian Nerve
3 & 4. The Vidian nerve travels to the Pterygopalatine Ganglion where the GVE - parasympathetics from the Greater Petrosal Nerve synapse.

37
Q

In addition to its GVE - parasympathetic fibers, what other fiber type does Chorda Tympani Posses?

A

SVA - Taste receptors

38
Q

What 3 Cranial Nerves have Gustatory Nerve endings that surround taste buds? What do these nerves mainly detect?

A

CNs VII, IX, X detect primarily water-soluble molecules called TASTANTS.

39
Q

What are the 2 types of sensory innervation of the tongue?

A
  1. TASTE (SVA)

2. General Sensory (GSA) - Somatic sensation

40
Q

Filiform Papillae of the anterior 2/3 contain what type of sensory nerve endings ONLY?

A

GSA - General Sensory. NO taste

41
Q

What is the only part of the tongue that has dual innervation?

A

The anterior 2/3 is innervated by the Chorda Tympani (CN VII - SVA) & the Lingual Nerve (CN V3 - GSA).

42
Q

What nerve provides Taste sensation (SVA - Gustatory Receptors) to the anterior 2/3 of the tongue? What is the path along which taste sensation is conveyed?

A

The Gustatory Receptors of the anterior 2/3 of the tongue convey information via the CHORDA TYMPANI to the GENICULATE GANGLION and on to the NUCLEUS SOLITARUS.

43
Q

What nerve conveys General Sensory Inputs from the Filiform Papillae of the anterior 2/3 of the tongue?

A

The LINGUAL NERVE of V3.

44
Q

GUSTATORY PATHWAYS in general consist of Central projections (to CNS) of taste afferents in peripheral ganglia that project to what point in the MEDULLA?

A

SVA - Gustatory Sensory nerves - convey sensation to the NUCLEUS SOLITARIS (or Nucleus of the Solitary Tract) in the MEDULLA (CNS).

45
Q

What are AQUESIA HYPOGEUSIA and DYSGUESIA? What causes these conditions?

A

Aquesia Hypoguesia = diminished taste
Dysgeusia = Interruption in taste
-Both are cause by Gustatory Dysfunction.

46
Q

The Greater Petrosal Nerve (which is not usually considered to have SVA fibers) may carry some taste fibers from what area?

A

The SOFT PALATE.

47
Q

What is the 1 branch of the facial nerve that contains GSA fibers?

A

The POSTERIOR AURICULAR NERVE

48
Q

The POSTERIOR AURICULAR NERVE contains what 2 nerve fiber types?

A
  1. GSE - Branchial motor nerves

2. GSA - General Sensation

49
Q

What 2 muscles do the GSE - branchial motor nerves - of the Posterior Auricular Nerve innervate?

A
  1. AURICULARES Muscle

2. OCCIPITALES Muscel

50
Q

What 3 structures of and around the AURICLE are the GSA fibers of the Posterior Auricular Branch of CN VII responsible for innervating?

A
  1. Skin of the CONCHA of the External Ear
  2. A small patch of skin behind the ear
  3. A portion of the superficial aspect of the TYMPANIC MEMBRANE
    Note: For 1 & 2, think of class slide of ear w/ blue dots!
51
Q

BELL’S PALSY will result from a peripheral (Infranuclear) lesion of what cranial nerve at or distal to the Stylomastoid Foramen?

A

Facial Nerve - CN VII