Cranial Nerves (Quiz 2) Flashcards
Which cranial nerves are attached to the brainstem?
CN III-XII
What are the 4 axonal categories (same for spinal cord and cranial nerves)?
1) somatic sensory (pain, temp, mechanical, tactile)
2) visceral sensory (sensory input from organs and blood vessels)
3) visceral motor (preganglionic ANS axons)
4) skeletal motor (goes out to skeletal muscles with alpha and gamma motor neurons)
What 2 additional axonal categories do cranial nerves have?
1) special sensory (special anatomy or have their own pathway , ex: photoreceptor, olfactory receptor, or gustatory receptor)
2) pharyngeal motor (also called brachial motor, these are the muscles of larynx, pharynx, jaw, and face)
note: anything that moves the eyes or tongue is skeletal motor, but if its any other muscle of the face then it is pharyngeal motor
During development, the arrangement of the afferent and efferent spinal cord column is formed. The sulcus limitans is the border between the dorsal and ventral horns. _____________ function is always closest to the sulcus limitans. This pattern is seen in the brainstem
Visceral
The sulcus limitans runs along the floor of the ventricle. Sensory is ____________, motor is _________. Visceral is closest to the sulcus limitans as seen in the spinal cord.
lateral, medial
note: cell columns for the categories of fiber are NOT continuous in the brainstem- separate nuclei
T/F: nuclei correspond to the level of the attachment of the nerve
true
T/F: all types of axonal fibers are present at each brainstem level
false
T/F: no cranial nerve has axons from all 6 categories
true
Generally speaking, what are the 3 types of cranial nerves?
1) motor CNs (CN 3, 4, 6, 11, and 12)
2) special sensory CNs (CN 1, 2, and 8)
3) mixed CNs (CN 5, 7, 9 and 10)
What is A?
CN III
What is B?
CN IV
What is C?
CN V
What is D?
CN VI
What is E?
CN VII
What is F?
CN VIII
What is G?
CN IX
What is H?
CN X
What is I?
CN XII
What are the motor cranial nerves that originate in the brainstem?
CN 3, 4, 11, and 12
The oculomotor nerve (CN 3) is a motor nerve with efferent to….
-levator palpebrae superioris
-medial, superior, and inferior rectus, and inferior oblique (4/6 extraocular eye muscles)
The nuclei for CN III is in the rostral midbrain. What is the nucleus called?
oculomotor nucleus
The oculomotor nucleus is a wedge shaped nucleus located at the anterior edge of the _________________
periaqueductal gray
The accessory oculomotor or __________________ nucleus sits in the midline and is the ANS output to the ciliary ganglion and pupillary sphincter and ciliary muscle
Edinger Westphal
The oculomotor nucleus to the levator palpebrae superioris innervates ________________
bilaterally
The oculomotor nucleus to the superior rectus projects _______________
contralaterally
The oculomotor nucleus to the medial, inferior rectus, and inferior oblique projects ____________
ipsilaterally
What does the superior branch of the oculomotor nerve innervate?
superior rectus and levator palpabrae superioris
What does the inferior branch of the oculomotor nerve innervate?
inferior rectus, medial rectus, and inferior oblique
Which muscle elevates the eyeball?
superior rectus
Which muscle raises the upper eyelid?
levator palpabrae superioris
Which muscle depresses the eyeball?
inferior rectus
Which muscle adducts the eyeball?
medial rectus
Which muscle elevates, abducts, and laterally rotates the eyeball?
inferior oblique
The trochlear nerve is a motor nerve and it innervates 1 extraocular muscle. Which muscle is it?
superior oblique
Cells bodies for CN IV are located in the _____________ nucleus. It is located at the caudal midbrain at the level of the inferior colliculus
contralateral
Which CN axons leave the nucleus, turn caudally in the periaqueductal gray and project posteriorly? This is the ONLY CN that leaves posterior brainstem
CN IV
What is the only CN to originate entirely from a contralateral nucleus?
CN IV
Which cranial nerve gets its name as it innervates the lateral rectus and abducts the eye?
CN VI
What are the somatic CNs?
CN 3, 4, 6, and 12
What is the nucleus called for CN IV?
trochlear nucleus
Abducens fibers originate from the ___________ abducens nucleus
ipsilateral
The abducens nucleus is located in the caudal ______ beneath the floor of the ____________. Adjacent to the abducens nucleus is the medial longitudinal fasciculus (MLF) and the motor axons of the facial nerve (CN VII). CN VII fibers wrap around the abducens nucleus forming the internal genu of the facial nerve. The abducens nucleus and the internal genu form the facial colliculus in the floor of the 4th ventricle
pons, 4th ventricle
What is the nucleus for the accessory nerve?
ambiguous nucleus
What does the accessory nerve innervate?
traps and SCM
The hypoglossal nerve originates in the __________ nucleus which extends from the caudal to rostral medulla. This nucleus is directly adjacent to the midline of the medulla. On the floor of the 4th ventricle. It is also just medial to the large dorsal motor nucleus of the vagus
hypoglossal
CN XII enters the tongue inferiorly innervating….
intrinsic and extrinsic tongue muscles
The hypoglossal nerve fibers originate in the _____________ hypoglossal nucleus, axons project anteriorly and emerge as rootlets in a groove between the pyramid and olive
ipsilateral
