Cranial Nerves Flashcards
what are the cranial nerves responsible for?
all innervation of the head except for the back of the head and posterior to the ears
what are the three types of motor fibers?
somatic, branchial, and visceral motor
what are the three types of sensory fibers?
visceral, general, and special sense
what are somatic motor fibers?
efferent fibers, which are typically voluntary skeletal muscles
what are branchial motor fibers?
voluntary muscles, but are derived from embryological structures on the ventral half of the body; the branchial arches
what are visceral motor fibers?
the effector fibers of the parasympathetic system
what are visceral sensory fibers?
these are the rarest fibers. they are fibers that monitor sensations in hollow tubes such as blood vessels, digestive tract organs etc which we are not normally aware of
what are general sensory fibers?
afferent fibers such as touch, temperature, pain
what are special sense fibers?
fibers of smell, vision, taste, hearing, and balance
what is cranial nerve one?
olfactory nerve
where does olfactory nerve emerge from?
from the CNS from under the inferior surface of the cerebral cortex, at the olfactory trigone
where does the olfactory nerve exit the cranium?
via the foramina in the cribriform plate of the ethmoid bone
what is the target of the olfactory nerve?
the primary olfactory area which includes the uncus of the temporal lobe and part of the hippocampus and terminates in the olfactory muscosa of the nose
T/F this nerve contains the only afferent fibers reaching the cortex that do not relay through the thalamus
True
what type of fibers does the olfactory nerve carry?
special sensory fibers for he special sense of smell
what is cranial nerve 2?
optic nerve
where does the optic nerve enter?
into the CNS in the forebrain and diencephalon
where do the fibers of the optic nerve arise from?
ganglion cells in the retina
where do the fibers of the optic nerve exit?
they exit the posterior orbit through an opening in the lesser wing of the sphenoid bone called the optic canal to then enter the middle cranial fossa
what do the optic nerve fibers cross through to continue posteriorly as the optic tracts?
optic chiasm
what is the destination of the optic nerve?
the geniculate bodies of the thalamus and the occipital cortex of the occipital lobe
what type of fibers does the optic nerve carry?
special sensory fibers for the special sense of vision
what is the third cranial nerve?
oculomotor nerve
where does the oculomotor nerve emerge?
from the CNS the midline between the midbrain and pons
where does the oculomotor nerve exit the cranium?
through the superior orbital fissure which lies between the greater and lesser wings of the sphenoid bone into the orbit
what is the destinations of the oculomotor nerve?
the intracoular muscles (constrictor pupillae and cilliary muscles) and 4 of the 6 extraocular muscles ( superior rectus, medial rectus, and inferior rectus, and inferior oblique muscle)
what type of fibers does the oculomotor nerve carry?
somatic motor fibers (general somatic efferent fibers) and visceral motor fibers (general visceral efferent fibers)
what is the fourth cranial nerve?
trochlear nerve
where does the trochlear nerve emerge from?
the CNS on the posterior aspect of the midline of the midbrain
Does the trochlear nerve emerge from dorsal or ventral side?
dorsal
where does the trochlear nerve exit?
through the superior orbital fissure to reach the orbit
what is the destination of the trochlear nerve?
superior oblique muscle of the eye
what type of fibers does the trochlear nerve carry?
somatic motor fibers (general somatic efferent fibers)
what is the fifth cranial nerve?
trigeminal
where does the trigeminal nerve emerge from?
the lateral aspect of the pons within the cavernous sinus
what are the three divisions of the trigeminal nerve?
ophthalmic V1, maxillary V2, and mandibular V3
where does the ophthalmic division exit the cranium?
superior orbital fissue
what does the ophthalmic division supply?
the skin on the front of the head and the nose
what type of fibers does the ophthalmic division carry?
general sensory fibers (general sensory afferent fibers)
where does the maxillary division exit the cranium?
through the foramen rotundum
what does the maxillary division supply?
the skin of the upper jaw upper teeth/gums, and the palate and some meninges
what type of fibers does the maxillary division carry?
general sensory fibers (general sensory afferent fibers)
where does the mandibular division exit the cranium?
through foramen ovale
what does the mandibular division supply and with what fibers?
the muscles of mastication (mylohyoid, anterior digastric) muscles of the eardrum, the soft palate, and muscles under the mandible with branchial motor fibers (especially visceral efferent fibers) and then sensory information from the lower face, anterior 2/3 of the tongue, lower teeth/gums, some meninges and a small bit of the skin around the external auditory meatus via general sensory fibers (general sensory afferent fibers)
what is the sixth cranial nerve?
abducens nerve
where does the abducens nerve emerge from?
the CNS at the inferior border of the pons on the ventral side
where does the abducens nerve exit?
through the superior orbital fissure
what is the destination of the abducens nerve?
lateral rectus muscle of the eye
what type of fibers does the abducens nerve carry?
somatic motor fibers (general somatic efferent fibers)
what is the name of the seventh cranial nerve?
facial nerve
where does the fascial nerve emerge from?
the CNS on the junction between the pons and the medulla on the brainstem
where does the fascial nerve exit?
the internal acoustic meatus
which cranial nerve passes through the parotid gland (NOT INNERVATED BY IT)
fascial known as the parotid plexus
what are the four types of fibers of the fascial nerve?
branchial motor (special visceral efferent fibers), visceral motor fibers (general visceral efferent fibers), general sensory fibers (general somatic afferent fibers), and special sensory fibers (special afferent fibers)
what do the branchial motor fibers of the fascial nerve supply?
the muscles of fascial expression, auricular muscles, the posterior bellies of the digastric muscles, stylohyoid muscles and the stapedius muscles
what do the visceral motor fibers of the fascial nerve supply?
lacrimal gland, submandibular and sublingual glands
what do the general sensory fibers of the fascial nerve supply?
general sensory information to very few areas of the skin
what do the special sensory fibers of the fascial nerve supply?
the special sense of taste for the anterior 2/3 of the tongue, the hard and soft palates, which are provided by the chorda tympani nerve
what is the eighth cranial nerve?
vestibulocochlear nerve
where does the vestibulocochlear nerve emerge from?
the junction between the pons and the medulla
where does the vestibulocochlear nerve exit the cranium?
the internal auditory meatus
when does the vestibulocochlear nerve separate and into what?
in the internal auditory meatus into the vestibular and the cochlear nerve
what type of fibers does the vestibulocochlear nerve carry?
special sensory fibers (special afferent fibers) to contribute to the special sense of hearing and balance
what is the ninth cranial nerve?
glossopharyngeal
where does the glossopharyngeal nerve emerge from?
the rostral medulla, more specifically the postolivary sulcus
where does the glossopharyngeal nerve exit the cranium?
the jugular foramen
what are the 5 different fibers the glossopharyngeal nerve carries?
branchial motor fibers (special visceral efferent fibers)
visceral motor fibers (general visceral efferent fibers)
visceral sensory fibers (general visceral afferent fibers)
general sensory fibers (general somatic afferent fibers)
special sensory fibers (special afferent fibers)
what does the branchial motor fibers of the glossopharyngeal nerve supply?
the striated muscle, the stylopharyngeus muscle (longitudinal muscle of the pharynx)
what does the visceral motor fibers of the glossopharyngeal nerve supply?
the otic ganglion which sends nerve fibers to stimulate the parotid gland
what does the visceral sensory fibers of the glossopharyngeal nerve supply?
carries sensory information from the carotid body and the carotid sinus
what does the general sensory fibers of the glossopharyngeal nerve supply?
provides general sensation to the posterior 1/3 of the tongue, the skin of the external ear, and the internal surface of the tympanic membrane
what does the special sensory fibers of the glossopharyngeal nerve supply?
provides the special sense of taste for the posterior 1/3 of the tongue
what is the name of the tenth cranial nerve?
vagus
where does the vagus nerve emerge from?
a medullary level in the postolivary sulcus as a series of rootlets just inferior to CN IX
where does the vagus nerve exit the cranium?
jugular foramen
what are the four types of fibers the vagus nerve carries?
branchial motor fibers (special visceral efferent fibers)
visceral motor fibers (general visceral efferent fibers)
visceral sensory fibers (general visceral afferent fibers)
general sensory fibers (general somatic afferent fibers)
what does the branchial motor fibers of the vagus nerve supply?
the constrictor muscles of the pharynx and the palatoglossus muscle of the tongue
what does the visceral motor fibers of the vagus nerve supply?
smooth muscles and glands of the pharynx and larynx, bronchi, aorta, heart, esophagus, and the abdominal visera
what does the visceral senosry fibers of the vagus nerve supply?
relay sensory information from the larynx, trachea, esophagus, thoracic and abdominal viscera
what does the general sensory fibers of the vagus nerve supply?
sensory information to the skin at the back of the ear and in the external auditory meatus
what is the eleventh cranial nerve?
accessory nerve
where does the accessory nerve emerge from?
postolivary sulcus of the medulla and it contains several cervical spinal roots through the foramen magnum
where does the accessory nerve exit the cranium?
jugular foramen
what are the targets of the accessory nerve?
the trapezius and sternocleidomastoid with motor innervation
what type of fibers does the accessory nerve carry?
branchial motor fibers (special efferent fibers)
what is the twelfth cranial nerve?
hypoglossal
where does the hypoglossal nerve emerge from?
between the pyramids and the olives of the medulla
where does the hypoglossal nerve exit the cranium?
the hypoglossal canal
what does the hypoglossal nerve innervate?
the intrinsic and extrinsic muscles of the tongue except for the palatoglossus muscle
what type of fibers does the hypoglossal nerve carry?
somatic motor fibers (general somatic efferent fibers)
