Cranial nerves 2

Question 1

what neurons are in V trigeminal nerve ?

Answer 1

.mainly sensory with some motor
. sensory because it is the principal somatic sensory ( touch , pain , temperature/thermal ) nerve for face and head

. motor just supplies muscle of mastication ( chewing )

Question 2

why it called trigeminal nerve ?

Answer 2

. because there are 3 major nerves that come together to form the trigeminal nerve
. 3 separate nerve divisions
ophthalmic divison - goes through superior orbital fissure( V1)
maxillary ( V2 )
mandibular ( V3 )
-each of these 3 branches of trigmenial either enter or exit through 3 separate holes in the skull.
. 3 separate foramens 1 for each division : superior orbital fissure(ophthalmic) , foramen rotundum (maxillary) , foramen ovale respectively (mandibular)

Question 3

what are the 3 trigeminal divisions location and function ?

Answer 3

1. ophthalmic : somatic sensation skin of forehead , upper eyelid + cornea surface and inside the eye
2. maxillary : from skin of the lower eyelid , cheek + upper teeth and nasal mucosa
3. mandibular : from skin and teeth of lower jaw + tongue and also contains motor output to the chewing muscles

Question 4

what is test of ophthalmic nerve function ?

Answer 4

corneal - eyeblink reflex

Question 5

what neurons innervate facial nerve VII?

Answer 5

-Has 3 compositions a nerve could have
- mixed sensory , motor and autonomic
.sensory : from taste buds on anterior 2/3 of tongue ( sweet , sour , salt )
. parasympathetic : supplies the lacrimal gland ( tear production ) via pterygopalatine ganglion + submandibular and sublingual salivary glands via the geniculate ganglion
foramen : internal auditory / acoustic meatus

Question 6

what is main function of facial nerve VII ?

Answer 6

runs form main motor nucleus which supplies to muscles of facial expression including some near the eye
e.g. orbicularis oculi and frontalis

Question 7

what does facial nerve pass through ?

Answer 7

internal auditory meatus

Question 8

what is the functions of orbicularis oculi ?

Answer 8

it closes the eyelids when you blink spreading the tear film over the cornea to keep it hydrated , thus preventing cornea dehydration and prevents cornea cracking which can cause cornea to go opaque and cause blindness

Question 9

what happens when you damage in VII facial nerve ?

Answer 9

causes a conditions called bell’s palsy

Question 10

how to test if someone has a bell’s palsy ?

Answer 10

ask them to look up and show teeth
if there is a dropping eyelid along with weakness or total paralysis on one side of the face and can’t close eyes that means that they may have bell’s palsy along

Question 11

how to treat upper eyelid palsy ?

Answer 11

insert gold weight
. eye kept open by voluntary contraction of LPS muscle
. relax LPS , eye closes by force of gravity

Question 12

how to treat eveted lower eyelid ?

Answer 12

tighten surgically
. creates a lateral pool of tears
. reduce lower lid length and prevents drooping

Question 13

how to treat dry eye ?

Answer 13

lubricating drops or ointments

. moisture chamber shields attached to spectacle frames , lessens tear evaporation

Question 14

what nerves innervate VII vestibulo-cochlear ?

Answer 14

pure sensory , originates from ear

Question 15

what are two different components of VII vestibulo - cochlear ?

Answer 15

. cochlear nerve : carries hearing / auditory information

. vestibular nerve : carries information regarding the position and movement of the head

Question 16

what is the foramen for VII vestibulo - cochlear ?

Answer 16

nerves leave via internal auditory / acoustic meatus

Question 17

what is example of vestibular dysfunctions ?

Answer 17

loss of VOR and oscillopsia

Question 18

what is the function of outer and middle ears ?

Answer 18

convert and amplify air pressure ( sound ) waves at ear drum and via the ossicles into mechanical movement of auditory receptors ( hair cells ) in the cochlea ( inner ear ) innervated by spiral ( cochlea ) ganglion cells

-cochlea sits close to a bone outside your head- called mastoid process

Question 19

What are the simple tests of auditory function ?

Answer 19

• using an Otoscope/auriscope

- Audiometry: detecting different sound frequencies

Question 20

What are the 3 different results fo the tests for auditory function?

Answer 20

-Normal Audible Frequency Range: 20Hz (bone vibration) to 20kHz
Amplitudes: 30dB (whisper); 60dB (normal conversation); 120 dB (aircraft)
-(1) Conductive hearing loss: affects outer or middle ear
common, mild/moderate (5-30dB), usually reversible (ear wax, ‘glue ear’)
sound detection via mastoid bone conduction will be unaffected
-(2) Sensory-neural hearing, hair cell damage: severe & irreversible
excess noise exposure; antibiotics (-cillins); age-related (presbycusis)
sound detection via mastoid bone conduction will also be absent

Question 21

What happens if you activate the bone of the mastoid process?

Answer 21

• it will vibrate and the stimuli through bone vibration will travels directly to cochlear, by passing the outer and middle ear
• and cause hair cells to be distorted and pick up sound.

Question 22

What are the 2 components related to the 8the nerve ?

Answer 22

-1. Vestibule (a.k.a. 2 Otolithic organs)
Utricle & Saccule
Hair cells monitor head position with respect to gravity

Test of function; Eye-righting reflex
Eyes rotate with head tilt

-2. 3 Semi-circular Canals
Horizontal, posterior, anterior
- have Hair cells which monitor angular head acceleration & deceleration in 3D space
Test of function; Vestibular-Ocular Reflex (VOR)
Eyes move opposite to head turn

Question 23

What is the IX Glossopharyngeal (9) nerve?

Answer 23

-Mixed sensory, motor & autonomic
-Sensory: somatic sensation from pharynx & posterior 1/3 of tongue + taste buds (bitter)
Parasympathetic: to Otic ganglion which supplies the parotid salivary gland

Question 24

What is the main function of IX Glossopharyngeal (9) nerve?

Answer 24

-Main function is voluntary motor( bit which arrises from a nucleus in your medulla of your brainstem),called = Nucleus Ambiguous send out axons to innervate stylopharyngeal muscles which elevate larynx to allow swallowing when contracted.

Question 25

What is the foramen for the IX Glossopharyngeal (9) nerve?

Answer 25

jugular foramen

Question 26

What is the test for the motor function of the IX Glossopharyngeal (9) nerve?

Answer 26

Test of motor function: ‘gag’ reflex

Question 27

What is the X vagus nerve?

Answer 27

• Mixed sensory, motor & autonomic
• Sensory: somatic (pain, thermal,pressure,temp) from these same regions & from (all the organs inside your body) thoracic + abdominal organs

Question 28

What is the X vagus nerve main function?

Answer 28

Main function, from Nucleus Ambiguous to muscles of pharynx, soft palate & larynx controlling swallowing & speech (recurrent laryngeal nerve to vocal cords)
-Important in controlling the movements of your vocal apparatus allowing you to talk.

Question 29

What is another main function of the X vagus nerve?

Answer 29

Another Main Function= Parasympathetic component which is massive, widespread to all thoracic + abdominal organs (for resting, digesting)
nucelus in medulla send axons out to a bunch of different ganglia in thorax and abdomen - resting and digestion

Question 30

What is the foramen for the vagus nerve?

Answer 30

Foramen: jugular foramen

Question 31

What are the tests for the motor function of the X Vagus nerve?

Answer 31

lesions of recurrent laryngeal nerve results in hoarse speech

Question 32

What does the vagus nerve pass through?

Answer 32

jugular foramen

Question 33

What is X| accessory nerve?

Answer 33

-Pure motor, 2 Divisions
-Innervates 2 voluntary muscles (sternocleidomastoid and trapezius )
-Larger = mainly supplies sternocleidomastoid (rotates head away) & trapezius (lifts shoulders) muscles
Smaller = some input to internal laryngeal & soft palate for speech production

Question 34

What is the foramen for the accessory nerve?

Answer 34

jugular foramen & foramen magnum

Question 35

What do the lesions in the accessory nerve cause?

Answer 35

difficulty in rotating the head towards the opposite side (sternocleidomastoid) & in elevating the shoulder on the affected side (trapezius

Question 36

What is the X|| hypoglossal nerve?

Answer 36

• Pure motor
• Hypoglossal Nucleus supplies intrinsic and extrinsic muscles of the tongue, movement for eating & speech production

Question 37

What is the foramen for the X|| hypoglossal nerve?

Answer 37

hypoglossal canal

Question 38

What are the lesions characterised by in the X|| hypoglossal nerve?

Answer 38

-by ‘fasciculation’ of intrinsic muscles (spasms, twitching) on the affected side & deviation towards the affected side on tongue extension due to paralysis/ weakness of extrinsic muscles

Question 39

What is the difference between intrinsic and extrinsic muscle?

Answer 39

rolling your tongue- contracting muscle inside tongue.
-poking tongue out- id contracting muscles underneath tongue and protruding it out of your mouth

-Different motor neurons in the hypoglossal nucleus will innervate intinstic or extrinsic muscles.

Question 40

Where does the hypoglossal nerve pass through?

Answer 40

hypoglossal canals ( near foramen magnum)

Question 41

What are the effects of someone having their right hypoglossal nerve lesion (damaged)?

Answer 41

-When poking tongue out it can’t protrude to the right side - moves to weakened side/ protrudes to direction of where the nerve is damaged and left side is good.

Question 42

What ganglia cells directly innervate the lacrimal gland?

Answer 42

pterygopalatine- hearing