CNS-FA17-Occulomotor & Trochlear & Abducens nerve Nerves Flashcards
The nucleus of the oculomotor nerve is located where?
At the level of the superior colliculus of the midbrain
On the ventral side of periaqueductal gray
Where do the neurons of the oculomotor nerve exit ?
Interpeduncular fossa
Where does the oculomotor nerve exit the crainium?
Supraorbital fissure
Which eye muscles does the oculomotor nerve innervate?
All except the Superior oblique(trochlear) and lateral rectus (Abducens)
What is the function of the lavator palpebrae superioris that separates it from the other eye muscles?
Lifts eyelid
*no action on the eye
T/F: Oculomotor nerve has general somatic efferent and General visceral efferent
True
What is nucleus that contains the preganglionic fibers of the oculomotor nerve?
Edinger-Westphal nucleus/ Accessory oculomotor
The the fibers of the parasympathetic component of the oculomotor nerve come from the edinger-westphal/accessory oculomotor go to?
Ciliary ganglion (synapse) —> postganglionic come out as short ciliary nerves —> constrictor papillae muscles of the iris and ciliary muscle
What are the ciliary muscles connected to that have a function of focusing the lens?
Zonular fibers
What are the functions of the parasympathetic component of the oculomotor nerve?
Control light that enters
Focus the lens
The oculomotor nerve splits into what two divisions?
Superior
Inferior
Which muscles are innervated by the superior division of the oculomotor nerve?
Levator palpebrae superioris
Superior rectus
Medial rectus
The inferior division of the oculomotor nerve innervates which muscles?
Inferior rectus
Inferior oblique
What are the two reflexes associated with the parasympathetic component of the oculomotor nerve?
Pupillary light
Accommodation (focus)
Pupillary light reflex:
T/F: Shining light into one eye, both pupils constrict.
True
Pathway for pupillary reflex?
Fibers from optic tract —> synapse in pretectal area in midbrain —> fibers split bilaterally passing into the edinger-weshphal nucleus —> ciliary ganglion —> constrictor pupillae muscles of iris
Pathway of accommodation reflex?
Contraction of both ciliary muscles to bend lens –> Stimulus goes to visual cortex —> midbrain (edinger-westphal) —> ciliary ganglion —> ciliary muscle
what does “Corticobulbar” mean
Tract travels from cortex to medulla (aka bulbar region)
Tract does not make it to spinal cord
Nerve with nucleus at the level of inferior colliculus, ventrally located at the periacqueductal gray?
Trochlear nerve
Where do the fibers of the trochlear nerve enter the orbit and innervates what muscles?
Superior orbital fissure
Superior oblique
What is the only cranial nerve that exits dorsal and ALL fibers cross to CL side?
Trochlear
T/F: Trochlear nerve has GSE and GSA
False: GSE only
Cranial nerve with nucleus at the level of the midpons at facial colliculus ?
Abducens
Fibers of the Abducens nerve exit where?
Pontomedullary junction
fairly medial at the level of pyramids
The abducens nerve enters the orbit via which opening and innervates which muscles?
Supraorbital fissure
Lateral rectus-abducts eye
T/F: Abducens nerve contains the parasympathetic component GSE
True
With the exception of this muscle all recti muscle have their origin on the medial side of the disc
Lateral rectus
Fully coordinated eye movement of:
Inferior oblique
Up and in
Fully coordinated eye movement of:
Medial rectus
Medially
Fully coordinated eye movement of:
Superior oblique
Down and In
Fully coordinated eye movement of:
Superior rectus
Up and out
Fully coordinated eye movement of:
Inferior rectus
Down and out
Fully coordinated eye movement of:
LAteral rectus
Laterally
Eye muscle action individually:
Inferior oblique
Up and out
Eye muscle action individually:
Superior oblique
Down and out
Eye muscle action individually:
Superior rectus
Up and in
Eye muscle action individually:
Inferior rectus
Down and in
