neuro1- chpt 14 C.Ns

brain & cranial nerves pt 2

CN I

• origin

• exit

• components

• function

OLFACTORY NERVE

• olfactory epithelium

• foramina in cribriform plate ethmoid bone

• special sensory

• smell

CN II

• origin

• exit

• components

• function

OPTIC NERVE

• retina

• optic foramina → optic chiasm → optic tracts → thalamus → occipital cortex (exit = optic canal)

• special sensory

• sight

CN III

• origin

• exit

• components

• function

OCULOMOTOR NERVE

• midbrain

• superior orbital fissure → orbit → split into superior/inferior branches

• motor: somatic & autonomic (visceral)

• movement of eye

somatic vs autonomic motor branches of CN III

somatic motor branches:

• 3 rectus mm

• 1 oblique

• levator palpebrae superioris

autonomic motor branches to ciliary ganglion:

• pupil (constiction)

• ciliary mm (lens accomo; seeing close/far)

CN IV

• origin

• exit

• components

• function

TROCHLEAR NERVE

• midbrain (only one that arises from post. aspect brain stem)

• superior orbital fissure

• somatic motor (to superior oblique mm)

• moves eye downwards / inward

CN VI

• origin

• exit

• components

• function

ABDUCENS NERVE

• pons

• superior orbital fissure

• somatic (to lateral rectus mm)

• abducts eye

CN V

• origin

• exit

• components

• function

TRIGEMINAL NERVE (largest cn)

• pons

• 3 branches:

  • ophthalmic = superior orbital fissure

  • maxillary = foramen rotundum

  • mandibular = foramen ovale

• mixed

  • sensory: touch, pain, temp

    • skin of face (only cn w/ dermatome)

    • tongue (not taste!)

    • mucosa, nose, mouth, nasopharynx, teeth, cornea

    : proprioception

    • mm of mastication & TMJ

  • motor (branchial motor nerves travel w/ mandibular division)

    • mm of mastication: masseter, temporalis, med/lat pterygoids

    • tensor veli palatine

    • mylohyoid, ant belly diagastric

    • tensor tympani mm (drowns sounds)

CN VII

• origin

• exit

• components

• function

FACIAL NERVE

• pons

• internal acoustic meatus → winding thru temporal bone (facial canal) → stylomastoid foramen to exit cranial base

  • once out of skull → passes parotid gland → innervates facial expression

• mixed (bronchial & visceral)

  • sensory: geniculate ganglion w/in temporal bone

  • taste (ant. 2/3 tongue)

  • brachial motor: mm of facial expression, stapedius, stylohyoid, posterior belly of digastric, platysma

  • autonomic (visceral) motor: all face glands EXEPT PAROTID

what nerve can be impacted during middle ear/inner ear infection

CN VII - facial nerve 7

(_) reflex: protects eyes from foreign bodies

corneal reflex

sensory arc of cornea

CN V (5: touch to surface of cornea)

motor arc of cornea

CN VII (7: orbicularis oculi)

CN VIII

• origin

• exit

• components

• function

VESTIBULOCOCHLEAR NERVE

• inner ear to pons

• passes thru internal acoustic meatus

• sensory

  • vestibular branch: equilibrium (balance)

  • cochlear branch: hearing

CN IX

• origin

• exit

• components

• function

GLOSSOPHARYNGEAL NERVE

• medulla oblongata

• jugular foramen

• mixed

  • sensory: superior & inferior ganglion

  • taste/general tongue sense (post. 1/3)

  • swallowing proprioception

  • carotid sinus (baroreceptors)

  • carotid body (chemoreceptors)

  • branchial motor: stylopharyngeus m

  • autonomic (visercal) motor: parotid gland thru otic ganglion

CN X

• origin

• exit

• components

• function

VAGUS NERVE

head, neck, thorax, abdomen (wide distribution thru body)

• medulla oblongata

• jugular foramen → passes neck & thoracic cavity → pierces diaphragm w/ esophagus → over viscerae of abdominal cavity → up to transverse colon

• mixed

  • sensory: aortic body, sensation from all viscerae (hungy/full)

  • branchial motor: mm of pharynx, larynx, soft palate

  • motor autonomic (visceral): heart lungs, GI tract motility, GI gland secretion, constriction of airways

sensory arc for gag reflex

CN IX (9: touch base of throat)

motor arc for gag reflex

CN X (10: response of pharynx)

CN XI

• origin

• exit

• components

• function

SPINAL ACCESSORY NERVE

• medulla oblongata

• jugular foramen

• somatic motor:

  • traps, scm

CN XII

• origin

• exit

• components

• function

HYPOGLOSSAL NERVE

• medulla oblongata

• hypoglossal canal (innervates tongue from underneath)

• somatic motor

  • mm of tongue for speech/swallow

** NO TASTE SENSATION