cranial nerves

parasympathetic

“rest and digest”

* relaxation, heart rate slows, low breathing rate, tears to keep eyes lubricated…
* some cranial nerves have this function

olfactory nerve

CN I - sensory

origination: olfactory receptor cells → primary olfactory cortex

passageway: cribiform foramina

func: special sensation (CHEMORECEPTION → smell)

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optic nerve

CN II - sensory

o: retina → occipital lobe (visual cortex)

p: optic canal

f: special sense (vision; photoreception)

binocular vision

“crossing over” of medial aspect, lateral stays on same side.

* allows us to have depth perception, stereoscopic vision (3D)

oculomotor nerve

CN III - motor

o: midbrain

p: superior orbital fissure

f: 4/6 eye movement mm → superior rectus, inferior rectus, medial rectus, inferior oblique

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\*parasympathetic innervation

trochlear nerve

CN IV - Motor

o: midbrain

p: superior orbital fissure

f: innervating superior oblique m. only

trigemial nerve

CN V - both

3 divisions:

* V1: opthalmic
* sensory; top of face
* V2: maxillary
* sensory; middle face + upper teeth
* V3: mandibular
* sensory; lower face + teeth
* and motor to muscles of mastication

if dentist works on UPPER molar, where do they target / numb?

maxillary

(middle face/UPPER teeth)

trigeminal nerve: V1, V2, V3 origin to passageway

V1: pons → superior orbital fissure → supraorbital foramen

V2: pons → Foramen rotundum → infraorbital foramen

V3: pons → foramen ovale → mental foramen

abducens nerve

CN VI - Motor

o: pons → muscle

p: superior orbital fissure → CN III, CN IV, V1, VI

f: lateral rectus m. only

Facial nerve

CN VII - both

o: pons (both ways)

p: internal acoustic meatus

f:

* motor → m. facial expression + parasympathetic
* sensory → taste; anterior 2/3 of tongue (chemoreception)

facial nerve pathway/branch

chorda tympani branches off, passes through middle ear, goes to ant. 2/3 of tongue

facial nerve (CN VII) 5 branches that innervate muscle of facial expression

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facial nerve dysfunction is called

bells palsy

* facial paralysis
* possible taste disturbance
* dry eye/mouth

vestibulocochlear nerve

CN VIII - sensory

o: pons + medulla

p: internal acoustic meatus

f: special sense: hearing + equilibrium

glossopharyngeal nerve

CN IX - both

o: medulla

p: jugular foramen

f:

* motor: stylopharyngeous m. + parasympathetic
* sensory: taste; posterior 1/3 of tongue + general sensation - post 1/3 tongue of pharynx

vagus nerve

CN X - both

o: medulla

p: jugular foramen

f:

* motor: muscles of pharynx + larynx + parasympathetic → thorax + abdomen
* sensory: general sense - epiglottis + lower pharynx

accessory nerve

CN XI - motor

o: medulla

p: jugular foramen (CN IX, X, XI)

f: sternocleidomastoid m. + trapezius m.

hypoglossal nerve

CN XII - Motor

o: medulla

p: hypoglossal canal

f: tongue m.

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damage to this nerve → push tongue towards damaged side of tongue