cranial nerves

Question 1

how many pairs of cranial nerves are there?

Answer 1

12

Question 2

what different types of fibres can cranial nerves contain?

Answer 2

somatic motor fibres
visceral motor fibres
visceral sensory fibres
general sensory fibres
special sensory fibres

Question 3

what do somatic motor fibres supply?

Answer 3

striated muscle

Question 4

what do visceral motor fibres supply?

Answer 4

smooth muscle and glands

Question 5

what do visceral sensory fibres receive input from?

Answer 5

pharynx
larynx
heart
lung 
gut

Question 6

what do general sensory fibres receive afferent inputs from?

Answer 6

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

Question 7

where are the cell bodies for sensory fibres located?

Answer 7

outwith the CNS

Question 8

where are the cell bodies for somatic motor fibres located?

Answer 8

inside the CNS

Question 9

where are the cell bodies for autonomic motor fibres located?

Answer 9

within the CNS and outwith the CNS at synapses

Question 10

what is cranial nerve 1 and what is its function?

Answer 10

olfactory - sensory (smell)

Question 11

what is cranial nerve 2 and what is its function?

Answer 11

optic - sensory (vision)

Question 12

what is cranial nerve 3 and what is its function?

Answer 12

oculomotor - motor (eye movement)

Question 13

what is cranial nerve 4 and what is its function?

Answer 13

trochlear - motor (eye movement)

Question 14

what is cranial nerve 5 and what is its function?

Answer 14

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

Question 15

what is cranial nerve 6 and what is its function?

Answer 15

motor (eye movement)

Question 16

what is cranial nerve 7 and what is its function?

Answer 16

mixed (muscles of facial expression, parasympathetic, taste)

Question 17

what is cranial nerve 8 and what is its function?

Answer 17

vestibulocochlear - sensory (hearing and balance)

Question 18

what is cranial nerve 9 and what is its function?

Answer 18

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

Question 19

what is cranial nerve 10 and what is its function?

Answer 19

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

Question 20

what is cranial nerve 11 and what is its function?

Answer 20

motor - (soft palate, throat and neck)

Question 21

what is cranial nerve 12 and what is its function?

Answer 21

motor- tongue

Question 22

what is the pathway of the olfactory nerve?

Answer 22

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

Question 23

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

Answer 23

tear in olfactory nerve resulting in anosmia

Question 24

what is the pathway of the optic nerve?

Answer 24

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

Question 25

what is the pathway of the oculomotor nerve?

Answer 25

emerges from midbrain and exits via superior orbital fissure

Question 26

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

Answer 26

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

Question 27

what is the pathway of the trochlear nerve?

Answer 27

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

Question 28

what is the pathway of the abducent nerve?

Answer 28

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

Question 29

what are some clinical signs of trochlear nerve damage?

Answer 29

diplopia when looking down

Question 30

what are some clinical signs of abducent nerve damage?

Answer 30

medial deviation of the affected eye causing diplopia

Question 31

what is the pathway of the opthalmic nerve (V1)

Answer 31

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

Question 32

what is the pathway of the maxillary nerve (V2)

Answer 32

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

Question 33

what is the pathway of the mandibular nerve (V3)

Answer 33

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

Question 34

what are some clinical signs of trigeminal nerve damage?

Answer 34

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

Question 35

what is the pathway of the facial nerve?

Answer 35

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

Question 36

what are some signs of facial nerve damage?

Answer 36

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

Question 37

what is the pathway of the vestibulocochlear nerve?

Answer 37

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

Question 38

what are some signs of vestibulocochlear nerve damage?

Answer 38

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

Question 39

what is the pathway of the glossopharyngeal nerve?

Answer 39

emerges from medulla and exits via jugular foramen

Question 40

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

Answer 40

loss of gag reflex and taste from back of tongue | associated with injuries to CNs X and XI - jugular foramen syndrome

Question 41

what is the pathway of the vagus nerve?

Answer 41

emerges from medulla and exits via jugular foramen, then everywhere

Question 42

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

Answer 42

emerges from medulla and exits via jugular foramen, then everywhere

Question 43

what is the pathway of the accessory nerve?

Answer 43

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

Question 44

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

Answer 44

weakness in turning head and shrugging shoulder

Question 45

what is the pathway of the hypoglossal nerve?

Answer 45

emerges from medulla and exits through the hypoglossal canal

Question 46

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

Answer 46

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