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Flashcards in cranial nerves Deck (46)
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1
Q

how many pairs of cranial nerves are there?

A

12

2
Q

what different types of fibres can cranial nerves contain?

A
somatic motor fibres
visceral motor fibres
visceral sensory fibres
general sensory fibres
special sensory fibres
3
Q

what do somatic motor fibres supply?

A

striated muscle

4
Q

what do visceral motor fibres supply?

A

smooth muscle and glands

5
Q

what do visceral sensory fibres receive input from?

A
pharynx
larynx
heart
lung 
gut
6
Q

what do general sensory fibres receive afferent inputs from?

A
afferent inputs (touch, temperature, pain)
from skin and mucous membranes
7
Q

where are the cell bodies for sensory fibres located?

A

outwith the CNS

8
Q

where are the cell bodies for somatic motor fibres located?

A

inside the CNS

9
Q

where are the cell bodies for autonomic motor fibres located?

A

within the CNS and outwith the CNS at synapses

10
Q

what is cranial nerve 1 and what is its function?

A

olfactory - sensory (smell)

11
Q

what is cranial nerve 2 and what is its function?

A

optic - sensory (vision)

12
Q

what is cranial nerve 3 and what is its function?

A

oculomotor - motor (eye movement)

13
Q

what is cranial nerve 4 and what is its function?

A

trochlear - motor (eye movement)

14
Q

what is cranial nerve 5 and what is its function?

A

mixed - (sensation from face & mouth, muscles of mastication)

15
Q

what is cranial nerve 6 and what is its function?

A

motor (eye movement)

16
Q

what is cranial nerve 7 and what is its function?

A

mixed (muscles of facial expression, parasympathetic, taste)

17
Q

what is cranial nerve 8 and what is its function?

A

vestibulocochlear - sensory (hearing and balance)

18
Q

what is cranial nerve 9 and what is its function?

A

glossopharyngeal - mixed (swallowing, sensation from tongue, parasymp.)

19
Q

what is cranial nerve 10 and what is its function?

A

vagus nerve - motor (soft palate, throat and neck)

20
Q

what is cranial nerve 11 and what is its function?

A

motor - (soft palate, throat and neck)

21
Q

what is cranial nerve 12 and what is its function?

A

motor- tongue

22
Q

what is the pathway of the olfactory nerve?

A

olfactory nerve fibres pass through foraminifera in cribriform plate of ethmoid bone and enter olfactory bulb in the anterior cranial fossa

23
Q

what can a fractured cribiform plate result in with regards to the olfactory nerve?

A

tear in olfactory nerve resulting in anosmia

24
Q

what is the pathway of the optic nerve?

A

enters via optic canal, nerves join to form optic chiasm, fibres from medial (nasal) half of each retina cross to form optic tract

25
Q

what is the pathway of the oculomotor nerve?

A

emerges from midbrain and exits via superior orbital fissure

26
Q

what are some clinical signs that the oculomotor nerve may be damaged?

A

ptosis
eyeball abducted and pointing down
no pupillary reflex
no accomodation of the lens

27
Q

what is the pathway of the trochlear nerve?

A

emerges from dorsal surface of the mid brain and exits via the superior orbital fissure

28
Q

what is the pathway of the abducent nerve?

A

emerges between pons and medulla and exits exits via the superior orbital fissure

29
Q

what are some clinical signs of trochlear nerve damage?

A

diplopia when looking down

30
Q

what are some clinical signs of abducent nerve damage?

A

medial deviation of the affected eye causing diplopia

31
Q

what is the pathway of the opthalmic nerve (V1)

A

emerges from the pons, travels through the trigeminal ganglion and exits via the superior orbital fissure

32
Q

what is the pathway of the maxillary nerve (V2)

A

emerges from the pons, travels through the trigeminal ganglion and exits via the foramen rotundum

33
Q

what is the pathway of the mandibular nerve (V3)

A

emerges from the pons, travels through the trigeminal ganglion and exits via the foramen ovale

34
Q

what are some clinical signs of trigeminal nerve damage?

A

paralysis of muscles of mastication
loss of corneal or sneezing reflex
loss of sensation in the face
trigeminal neuralgia

35
Q

what is the pathway of the facial nerve?

A

emerges between pons and medulla and exits via internal acoustic meatus, facial canal and stylomastoid foramen

36
Q

what are some signs of facial nerve damage?

A

Bell’s palsy - cannot frown, close eyelid, or bare teeth

37
Q

what is the pathway of the vestibulocochlear nerve?

A

emerges from between pons and medulla and exits via internal acoustic meatus, dividing into vestibular & cochlear nerves

38
Q

what are some signs of vestibulocochlear nerve damage?

A

tinnitus (ringing in the ears)
deafness (conductive vs sensorineural)
vertigo (loss of balance)
nystagmus (involuntary rapid eye movements)

39
Q

what is the pathway of the glossopharyngeal nerve?

A

emerges from medulla and exits via jugular foramen

40
Q

what are some signs that the glossopharyngeal nerve has been damaged?

A

loss of gag reflex and taste from back of tongue

associated with injuries to CNs X and XI - jugular foramen syndrome

41
Q

what is the pathway of the vagus nerve?

A

emerges from medulla and exits via jugular foramen, then everywhere

42
Q

what are some signs that the vagus nerve has been damaged?

A

emerges from medulla and exits via jugular foramen, then everywhere

43
Q

what is the pathway of the accessory nerve?

A

small cranial (medulla) and large spinal roots exit via jugular foramen

44
Q

what are some signs that the accessory nerve has been damaged?

A

weakness in turning head and shrugging shoulder

45
Q

what is the pathway of the hypoglossal nerve?

A

emerges from medulla and exits through the hypoglossal canal

46
Q

what are some signs that the hypoglossal nerve has been damaged?

A

causes paralysis & atrophy of ipsilateral half of tongue. Tip deviates towards affected side