Flashcards in head: cranial nerves Deck (48)
where do these cranial nerves originate? CNI , CN II, CN XI
XI- spinal cord
olfactory nerve: where are the receptors, cell bodies, central processes and synapse ?
Receptors in roof of nasal cavity
Cell bodies in nasal mucosa
Central processes enter cranium via cribriform plate
Synapse in olfactory bulb
only CN to enter cerebrum
CN I- olfactory
Olfactory tracts project to where?
Olfactory tracts project to ipsilateral & contralateral anterior temporal lobes
CN II: Optic “nerves” are ___ order neurons
Extensions of ________
3rd, extensions of diencephalon
Medial (nasal) retinal fibers cross & join lateral (temporal) retinal fibers of contralateral eye
Form optic tracts
R carries fibers from R half of each retina=left visual field
L carries fibers from L half of each retina=right visual field
where do the optic tracts project?
to thalamus then to occipital lobes
oculomotor: CN III - what does it do?
Somatic motor-eye/eyelid movement
Visceral motor-constricts pupil, rounds lens (accommodation)
Efferent limb of light reflex
CN III originates from two midbrain nuclei
2. Accessory/parasympathetic (Edinger-Westphal)-visceral
To ciliary ganglion
oculomotor nerve + CN IV + CN VI course
Courses lateral to diaphragm sella, crosses internal carotid
Enters orbit via superior orbital fissure
Short ciliary nerves (V1) go where?
to sphincter pupillae & ciliary body
what is the largest true cranial nerve?
CN V (trigeminal)
trigeminal nerve: made of how many brainstem nuclei? - how many are sensory and how many motor? which are larger? where does it emerge from?
4 brainstem nuclei-3 sensory, 1 motor
sensory (large) & motor (small) roots
*Sensory root has central processes from trigeminal (semilunar) ganglion
trigeminal ganglion is ____ to cavernous sinuses
do all trigeminal nerve fibers go through the trigem ganglion?
NO! sensory do, but Motor root fibers bypass ganglion
--> Blend with V3 in foramen ovale
three branches of opthalmic V1 and their subdivisions
Frontal: Supraorbital/supra trochlear
Nasociliary: Long/short ciliary, Infratrochlear
afferent limb of sneeze reflex
while V2 has 5 branches, which 2 do we care about? what are their subdivisions?
Zygomatic: Zygomaticofacial, Zygomaticotemporal
Infraorbital: Anterior superior alveolar
what are the 4 ganglia in the head? what nerve carries ALL postgang PSNS?
- Postganglionic parasympathetic from all ganglia carried by CN V branches
where does CN VI (abducens) enter to orbit?
comes from posterior cranial fossa
Enters at clivus
- enters orbit via SOF
which nerve has the longest intradural course?
which CN has the longest interosseus course?
where does the facial nerve enter and exit
enter: IAM (facial canal)
exit: stylomastoid foramen
where does the facial nerve take a sharp bend?
at the geniculate ganglion
three interosseus branches of CN VII (facial)
Nerve to stapedius
Chorda tympani (of facial nerve) enters infratemporal fossa via ______ _______ to meet with lingual V3
what innervates the stapedius (muscle that stabilizes the stapes)?
Branch to stapedius from facial nerve CN VII
Facial nerve CN VII- exits cranium via what? to become what 5 extracranial branches?
temporal, zygomatic, buccal, marginal mandibular, cervical