Cranial Nerves Flashcards

1
Q
\_\_ pairs of spinal nerves.
\_\_ Cervical
\_\_ thoracic 
\_\_ lumbar 
\_\_ sacral
\_\_ coccygeal
A
31 pairs
8 cervical
12 thoracic
5 lumbar
5 sacral 
1 coccygeal
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2
Q

Which cranial nerves have CNS characteristics?

Which have PNS characteristics?

A

CNS- CN I and CN II (has meninges coverings) Strictly sensory. Soma of those neurons are in the CNS.
PNS- CN III to CN XII

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3
Q

Where do CN I and Cn II originate

A

In the prosencephalon (forebrain, contains diencephalon and telencephalon)

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4
Q

Where do CN 3-12 originate?

A

Originate in the mesencephalon (midbrain) and the rhombencephalon (hindbrain, contains metencephalon- pons and cerebellum)

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5
Q

Mnemonics for name and function

A

Name- On occasion our trusty truck acts funny. Very good vehicle any how.
Function- Some say money matters, but my brother says big brains matter more.

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6
Q

Mesencephalon

A

Midbrain

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7
Q

Rhombencephlon

A

Hindbrain. Contains metencephalon (pons and cerebellum) and the myelencephalon (medulla)

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8
Q

Metencephalon

A

Pons and cerebellum. Within the rhombencephalon (hindbrain)

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9
Q

Myelencephalon contains

A

Medulla. Within the rhombencephalon (hindbrain)

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10
Q

Typically, nerves that emerge from the medial brainstem are __
Typically, nerves that emerge from the lateral brainstem are __
Typically, nerves that emerge between them are ___

A

medial- Motor, efferent, outbound (exiting CNS)
lateral-Sensory, afferent, inbound (arriving at CNS)
middle- Mixed

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11
Q

2 categories of somatic afferent components

A
  1. General (GSA)
    -Typical touch/pain sensations (true somatic afferent)
    -Fibers convey impulses from the skin and skeletal muscle spindles.
    -CN V1, V2, V3, VII, IX, X
    2 .Special (SA)
    -Involved with CN II and VIII (hearing and balance)
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12
Q

General somatic efferent (GSE)

A

Somatomotor function (true somatic efferent)
-Skeletal muscles whose origins are not derived from the branchial/pharyngeal arches. This includes extra ocular muscles, tongue muscle.
CNIII, IV, VI, and XII

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13
Q

2 Categories of visceral efferent

A
  1. General (GVE)- Innervate smooth muscles, cardiac muscles. Spinal nerves can carry GVE fibers. CN 7, 9, and 10
  2. Special (SVE)- Goofy one. Not autonomic. Innervate skeletal muscles deep in the neck and face. (deep muscles are usually smooth). Branch of CN V, 7, 9, 10th and part of the 11th (called the cranial root)
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14
Q

2 Categories of the visceral afferent

A
  1. General (GVA)- Fibers convey impulses from the sensory receptors in the viscera and blood vessel walls (true autonomic efferent)
    CN 9 and 10.
  2. Special (SVA)- Olfactory and gustatory (taste) senses. Cn 1, 7, 9, and 10.
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15
Q

What cranial nerves are located in the telencephalon (within the proencephalon)

A

CN I (olfactory)

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16
Q

What cranial nerves are located in the Diencephalon (within the proencephalon)

A

CN II (optic)

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17
Q

Proencephalon

A

Contains the diencephalon and the telencephalon

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18
Q

What cranial nerves are located in the mesencephalon

A

CN III (oculomotor) and CN IV (trochlear)

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19
Q

What cranial nerves are located in the metencephalon (pons)?

***Division of the rhombencephalon (hindbrain)

A
CN V (trigeminal) 
CN VI (Abducens)
CN VII (facial)
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20
Q

What cranial nerves are located in the myelencephalon (medulla) ?

***Division of the rhombencephalon (hindbrain)

A
CN VIII (Vestibulocochlear) 
CN IX (Glossopharyngeal) 
CN X (Vagus) 
CN XI (Accessory spinal)
CN XII (Hypoglossal)
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21
Q

CN I

A

olfactory

sensory

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22
Q

Olfactory cranial nerve

A

CN I

sensory

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23
Q

CN II

A

Optic nerve

Sensory

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24
Q

CN III

A

Oculomotor nerve

motor

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25
Q

Oculomotor nerve

A

CN III

motor

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26
Q

CN IV

A

Trochlear nerve

motor

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27
Q

Trochlear nerve is CN #

A

IV

motor

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28
Q

CN V

A

Trigeminal

both

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29
Q

CN VI

A

Abducens

motor

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30
Q

Abducens nerve is CN #

A

VI

motor

31
Q

CN VII

A

Facial

both

32
Q

The facial nerve is CN #?

A

VII

both

33
Q

CN VIII

A

vestibulocochlear

sensory

34
Q

The vestibulocochlear nerve is CN #

A
CN VIII (8) 
sensory
35
Q

CN IX

A

Glossopharyngeal

both

36
Q

The glossopharyngeal nerve is CN #?

A

IX

both

37
Q

CN X

A

Vagus

both

38
Q

Vagus nerve is CN #?

A

X

both

39
Q

CN XI

A

Accessory/spinal accessory

motor

40
Q

The accessory nerve is CN #?

A

XI

motor

41
Q

CN XII

A

Hypoglossal

motor

42
Q

The hypoglossal nerve is CN #

A

XII

motor

43
Q

Branchial pharyngeal arches

A

6 total, only 4 are externally visible on a developing fetus.

Arch 1- Mandibular. Innervates temporalis, masseter, and anteiror belly of digastric. Important muscles in chewing.
Arch 2- Hyaloid
Arch 3-6: No special name

The 5th arch doesn’t really develop into anything.
6th arch fibers merge with 4th arch fibers.

44
Q

Brachial arch one (called the mandibular arch). CN derived and skeletal muscles it innervates?

A

CN: Madibiluar nerve, which is a branch of trigeminal nerve

Skeletal muscles: Muscles involved with chewing. Temporalis, master, and digastric.

45
Q

Brachial arch two (called the hyaloid arch) CN derived and skeletal muscles it innervates?

A

CN: Facial, CN VII
Skeletal: Innervates muscles of facial expression.

46
Q

Brachial arch 3. CN derived and skeletal muscles it innervates?

A

CN: Glossopharyngeal (CN IX)
Skeletal: muscles of the pharynx. Swallowing. Neck muscles.

47
Q

Brachial arch 4. CN derived and skeletal muscles it innervates?

A

CN: Vagus, CN X. Tends to merge with arch 6.
Skeletal: cricothyroid

48
Q

Brachial arch 6. CN derived and skeletal muscles it innervates?

A

CN: Vagus (CN X) and possibly spinal accessory (CN XI). Tends to merge with arch 4.
Skeletal: Intrinsic laryngeal muscles

49
Q

Sensory ganglia in the head and which CN do they associate with

A

CN V- Trigeminal and geniculate
CN VIII- spiral and vestibular
CN IX- superior ganglion, and inferior petrosal
CN X- Superior (jugular) and inferior (nodose) ganglia.

Analagous to dorsal root ganglia adjacent to the spinal cord
Pseudounipolar neurons.

50
Q

Sensory ganglia in the head are associated with which cranial nerves

A

5, 7, 8, 9, and 10

51
Q

Autonomic ganglia in the head is exclusively ___

A

Parasympathetic

52
Q

Parasympathetic autonomic ganglia in the head and which CN do they associate with

A

CN III- Ciliary ganglion involved in pupillary constriction (miosis) and stimulates ciliary muscle to increase accommodation.

CN VII- Pterygopalatine ganglion found in the pterygopalatine fossa by ear. Stimulates lacrimal gland to increase tear production
Also the submandibular ganglion that stimulates the submandibular and sublingual gland

CN IX- Otic ganglion innervates parotid gland.

53
Q

TEST- What components are found in an autonomic ganglia?

A

CONTAINS CELL BODIES OF POSTSYNAPTIC (POSTGANGLIONIC) NEURONS

54
Q

Location and role of CN I- Olfactory Nerve (Sensory)

A
  • Considered to be a CNS nerve
  • Located through cribriform plate of the ethmoid bone. Nerves pass through the olfactory foramina (roots extending from the olfactory bulb)
  • SVA fibers only
  • If damaged, these fibers can sometimes grow back and person can regain sense of smell.
55
Q

Location and role of CN II- Optic nerve (sensory)

A

Retinal ganglion cells (RGC’s) originate in the retina and terminate in the lateral geniculate body (LGN) and some non-visual centers of the brain suchh as the pineal gland, pulvinar, superior colliculus.

  • Within common tendinous ring
  • Exits thru Optic canal
  • Present in the Middle cranial fossa as optic chiasm (which is superior to the cavernous sinus)

-SSA nerve fibers

56
Q

SVA. Think-

A

Smell and taste

57
Q

Naegleria

A

Ameoba in warm waters that enter through nasal cavity and infect CN I (olfactory) and then can enter the brain. Progressive. Death.

58
Q

Location and role of CN III- Oculomotor (Motor)

A

-As it enters the orbit through the common tendinous ring, it divides in the to superior division and the inferior division (3 branches)

Superior division- Innervates SR
Inferior division- 
Medial branch: MR
Central branch: IR
Lateral branch: IO and ciliary ganglion which is parasympathetic innervation 

-Travels through middle cranial fossa (within cavernous sinus) through the superior orbital fissure/annulus of Zinn.

GSE fibers- EOMs and levator
GVE fibers- Parasympathetic innervation to iris and ciliary muscles. Allows for miosis and accommodation.

59
Q

SSA think

A

Vision, hearing, balance

60
Q

Location and role of CN IV- Trochlear (Motor)

A
  • Enter the orbit through superior orbital fissure and passes ABOVE common tendinous ring
  • Exits middle cranial fossa within cavernous sinus DORSALLY (all other cranial nerves exit ventrally)
  • Long course makes it more susceptible to injury. Ex: trochlear nerve palsy (head tilt)
  • Innervates SO
  • GSE nerve fibers
61
Q

Typically, cranial nerves exit

A

Ventrally. Except CN IV (trochlear), it exits dorsally. This causes IV to be super long, and easily damaged.

62
Q

Location and role of CN V- Trigeminal (mostly sensory, but also has motor. So both)

A
  • Trigeminal (Semilunar or gasserian) ganglion in the hindbrain/pons. Houses soma of afferent (sensory) neurons.
  • GSA fibers are THE sensory nerves of the head.
  • SVE fibers ride along with sensory fibers in the mandibular division to innervate muscles of mastication.

V1- ophthalmic is sensory (GSA)
V2- maxillary is sensory (GSA)
V3- Mandibular is sensory AND motor (GSA and SVE)

63
Q

Which CNs enter through superior orbital fissure

A

3, 4, and 6

64
Q

CN 5b (maxillary) enters cavernous sinus how

A

Rotundum

65
Q

Which divisions of the trigeminal innervate

  1. Facial skin
  2. Nasal and pharyngeal mucosa
  3. Anterior 2/3 of tongue
  4. Muscles of mastication
A
  1. GSA fibers- ophthalmic, maxillary and mandibular
  2. GSA fibers- Ophthalmic and maxillary
  3. GSA fibers- mandibular
  4. SVE fibers (think brachial arches)- Mandibular
66
Q

3 divisions of CNV ophthalmic (GSA)

A
  • **Nasocilliary
  • Anterior and posterior ethmoid, infratrochlear, sensory root of ciliary ganglion, and long ciliary
  • **Frontal
  • Supraorbital and supratrochlear

***Lacrimal

67
Q

Dermatomes - what are they are where aren’t they located

A

Sensory/afferent innervation. Not present on face bc Cranial nerves innervate face sensory

68
Q

Ciliary ganglion

A
Sensory root (GSA) 
CNV- ophthalmic- nasocilliary - ciliary ganglion
69
Q

Maxillary division of CN V

A

GSA nerve fibers.

  • Sensory input is via zygomatic and infraorbial nerves at the inferior orbital fissure.
  • Within the pterygopalatine fossa, it travels posterior. Hits bone and then drills a hole (rotundum) and enters cavernous sinus. Sends branches to the pterygopalatine ganglion.
70
Q

Mandibular division of CN V

A

-enters/exit middle cranial fossa via foramen ovale. Does not travel through cavernous sinus

Branches:

  • Masseteric (M)
  • Medial pterygoid (M)
  • lateral pterygoid (M)
  • Auriculotemporal (S)
  • Lingual (S)
  • Inferior alveolar (B) innervates lower teeth. Long brach that terminates at mental nerve of mandible.
71
Q

Which divisions of CN V travel thru cavernous sinus

A

ophthalmic and maxillary

72
Q

Motor muscles of mastication

A

Lateral and medial pterygoids, masseter and temporals.

73
Q

Clinical assessment of CN V (sensory)

A

CN V1- forehead region
CN V2- cheek region
CN V3- chin

74
Q

Herpres Zoster Ophthalmic (HZO) can be also called

A

Ocular shingles. Portion of face with symptoms lets Dr know which portion of CN 5 is housing the virus.

Hutchinsons sign- If tip of nose is blistered, it is an indication that the eye is also involved since CN V1 innervates eyes and nasal portion.