20.7 NS: Cranial nerves 2 Flashcards
Where do CN I and II exit the skull?
I: Cribiform plate
II: Optic canal (within sphenoid)
After axons of CN II cross within the optic chiasm, where do they travel?
To lateral geniculate nucleus within thalamus (then to visual cortex)
Where do the nerves to the extraocular muscles exit the skull?
Superior orbital fissure (between greater and lesser wings of sphenoid)
Which muscles are controlled by CN III? What is the action? What is its visceral motor action?
CN III:
Extraocular muscles: MR, SR, IR, IO
elevates eyelid (levator palpebrae superioris)
PS to eye, pupils and ciliary muscle
Which cranial nerves exit the auditory canal?
CNVII, VIII
Which cranial nerves (and vein) exit the jugular foramen?
CNIX, X, XI and internal jugular vein
Where does CNXII exit?
Hypoglossal foramenh
Which CNs exit the superior orbital fissure?
CNIII, IV, VI, V1
What CN innervates Sphincter Pupillae? Which nucleus do these PS fibres come from?
CNII
PS fibres from Edinger Westfal nucleus
What does the trigeminal nerve do?
Sensory face
Motor: muscles of mastication and tensor tympani
Where do the trigeminal nuclei run?
What nuclei do they consist of?
Midbrain to upper spinal cord
Mesencephalic, chief sensory, spinal trigeminal nucleus (STN), motor nucleus
What are the divisions of the trigeminal nerve and where do they exit?
V1: Ophthalmic (SOF)
V2: Maxillary (foramen rotundum)
V3: Mandibular (foramenb ovale)
What can we use to test midbrain function?
What can we use to test pontine function?
Medulla function?
Pupillary light reflex
Corneal blink reflex
Gag reflex
What innervates the stapedius muscle? What does this muscle do?
VII, protects ear from loud noises
What PS, taste and sensation innervation does CN VII provide?
PS: lacrimal, sublingual, submandibular salivary glands
Taste: anterior 2/3rds tongue, soft palate
Sensation: small region next to external auditory meatus
What are the terminal branches of the facial nerve?
Temporal Zygomatic Buccal Mandibular Cervical
What are the order from the brainstem onwards of the divisions of the facial nerve
Greater petrosal
Branch to stapedius
Chorda tympani
Posterior auricular
Terminal branches (TZBMC)
Where does VIII exit the skull?
Internal acousitc meatus
What are the nuclei at the brainstem for the vestibulocochlear nerve?
Dorsal, ventral cochlear nuclei
Four vestibular nuclei
Where does CNIX exit the skull?
What does it do? (Sensory, taste, motor)
Jugular foramen
Sensory from tongue (post 1/3), pharynx, middle ear, carotid body
Taste: post 1/3 tongue
Motor: stylopharyngeus
What are the sensory/motor inputs and outputs for the gag reflex?
Sensory: IX to pharynx
Motor: X to pharynx
What does XI do?
Where is the nucleus? Where does it enter and exit
Shrugs shoulders, turns head
Nucleus in upper 5-6 of C
Enters: via foramen magnum
Exits: jugular foramen
What does hypoglossal innervate?
Muscles of tongue (except palatoglossus-CNX)
What are the exceptions of nuclei that receive input or provide output to one CN?
Solitarius
Ambiguus
Trigeminal
