Cranial Nerves Flashcards
What is the only cranial nerve that does not originate within the cranial cavity?
CN XI (Accessory)
It originates from the upper spinal cord, inferior to the occipital bone, enters the foramen magnum, then exits through the jugular foramen to reach its targets
Which cranial nerves are sensory only?
(3 total) The SA nerves for special sensees:
I (olfactory)
II (optic)
VIII (vestibulocochlear)
Which cranial nerves are motor only?
(5 total) III (occulomotor) IV (trochlear) VI (abducent) XI (accessory) XII (hypoglossal)
Which cranial nerves have mixed sensory and motor fibers?
V (trigeminal)
VII (facial)
IX (glossopharyngeal)
X (vagus)
Which cranial nerves carry parasympathetic fibers?
III (occulomotor)
VII (facial)
IX (glossopharyngeal)
X (vagus)
Where does sympathetic innervation in the head and upper neck originate?
preganglionic cell bodies reside in T1-T2 lateral horn gray matter and travel superiorly to the superior cervical ganglia, where they synapse with postganglionics, which follow the carotid arteries and branches in a plexus.
What are the divisions of the CN V?
the trigeminal nerve has 3 divisions:
V1 (opthalmic)
V2 (maxillary)
V3 (mandibular)
What is the name of CN IV?
trochlear
What is the name of CN IX?
glossopharyngeal
What is the name of CN XII?
hypoglossal
What is the name of CN VI?
abducent
Where is CN XI derived?
a. caudal brainstem
b. cranial brainstem
c. cranial spinal cord
d. caudal spinal cord
c. cranial spinal cord
caudal = tail end of body, so caudal brainstem would be the most inferior region of the brainstem (right around the foramen magnum)
cranial = close to the cranium so superior. The spinal cord ends superiorly near the foramen magnum as it meets the caudal brainstem.
T or F: Cranial nerves form by fusion of dorsal and ventral roots.
F. Spinal nerves do this. Cranial nerves are already mixed by the time they originate from the brainstem.
What type of fiber (GSA, GVA or SA) provides sensory innervation to the mucosal lining of the oral and nasal cavities?
GSA (the mucosal lining is derived from somatic mesoderm)
What type of fiber provides sensory innervation to the mucosal lining of the esophagus, larynx and trachea?
GSA (these mucosal linings are derived from somatic mesoderm)
Where would the cell body of a GSA fiber in a spinal nerve be found?
Dorsal Root Ganglia
Where would the cell body of a GSA fiber in a cranial nerve be found?
various sensory ganglia
Where would the cell body of a GVA fiber in a spinal nerve be found?
Dorsal Root ganglia
Where would the cell body of a GSE fiber in a spinal nerve be found?
Ventral horn of spinal cord gray matter
Where would the cell body of a GSE fiber in a cranial nerve be found?
brainstem motor nuclei
Where would preganglionic sympathetic fibers in a cranial nerve be found
nowhere. They follow the carotid plexus
Where would the cell bodies of parasympathetic fibers be found in a spinal nerve?
Gray matter of S2-S4
Name the type of fibers found in CN I
SA
Name the type of fibers found in CN II
SA
Name the type of fibers found in CN III
GSE and GVE
Name the type of fibers found in CN IV
GSE
Name the type of fibers found in CN V
GSA and BE
Name the type of fibers found in CN VI
GSE
Name the type of fibers found in CN VII
GSA, SA, BE, GVE
Name the type of fibers found in CN VIII
SA
Name the type of fibers found in CN IX
GSA, GVA, SA, BE, GVE
Name the type of fibers found in CN X
GSA, GVA, SA, BE, GVE
Name the type of fibers found in CN XI
GSE
Name the type of fibers found in CN XII
GSE
Which nerve is associated with the first branchiomeric arch?
CN V3 (mandibular branch of trigeminal)
Which nerve is associated with the second arch?
CN VII (facial)
Which nerve is associated with the third arch?
CN IX (glossopharyngeal)
Which nerve is associated with the fourth and sixth arches?
CN X (vagus)
What do muscles of the tongue and eye develop from?
somite mesoderm
What function do parasympathetics in the head serve?
constrict pupils
contract ciliary muscles
stimulate gland secretion (excluding sweat glands)
What function do sympathetics serve in the head?
sweat gland function
dilator pili muscle (if sympathetics fail, eyes will constrict. Think about fight or flight mode; when threatened, you will want to have the widest range of peripheral and distance vision possible so eyes will dilate)
Also arrector pili muscle and superior tarsal muscle but we haven’t learned these
Where are postganglionic sympathetic cell bodies of the head and neck located?
superior cervical ganglia
