CH14: Cranial nerves 2 Flashcards
Which reflexes involve the optic and oculomotor nerves?
- pupillary
- consensual
- accommodation
What is the pupillary reflex?
Pupil constricts when light is shined in the eye
What is the consensual reflex?
Pupil of eye constricts when light shined into opposite eye
What is the accommodation reflex?
- Lens adjusts to focus light on the retina
- Pupil constricts
- Pupils move medially
(when viewing object at close range)
What is the stimulus for the pupillary and consensual reflexes?
light shined in the eye
How are the eyes innervated by the ANS?
- parasympathetic (CN III, constricts pupil)
- sympathetic (dilates pupil)
3 branches of the trigeminal nerve
- ophthalmic (somatosensory)
- maxillary (somatosensory)
- mandibular (somatosensory/motor)
trigeminal nerve sensory nerve fibers transmit info from
- face
- TMJ
trigeminal nerve motor fibers transmit info to
muscles of mastication
Which reflexes are mediated by the trigeminal nerve?
- masseter
- corneal
What is the masseter reflex?
Masseter contracts when tapped with reflex hammer
masseter reflex
- afferents
- efferents
trigeminal (both)
What is the corneal reflex?
- “blink”
- Eyelids close when cornea is touched
corneal reflex
- afferents
- efferents
- trigeminal
- facial
Which muscles are innervated by the facial nerve?
- muscles of facial expression
- most glands in the head (salivary, nasal, lacrimal)
- eye closure
- lip movements
Aside from facial expression and glandular info, what other sensory info does the facial nerve convey?
- info from posterior ear canal
- taste from anterior tongue (to solitary nucleus)
- touch, pain, and pressure info from the tongue, pharynx, and skin near the ear canal to the trigeminal spinal nucleus
Where are signals to and from CN VII processed?
- pons
- medulla
- upper spinal cord
What are the branches of the vestibulocochlear nerve?
- vestibular branch
- cochlear branch
function of vestibular branch of CN VIII
Transmits information about head position and head movement
function of cochlear branch of CN VIII
transmits info related to hearing
Where are peripheral receptors for CN VIII functions?
in the inner ear (labyrinth)
labyrinth consists of
- vestibular apparatus
- cochlea
What does auditory information do in the CNS?
- orients head and eyes toward sounds
- increases activity level throughout the CNS
- provides conscious awareness and recognition of sounds
cochlea
Snail shell–shaped organ formed by a spiraling, fluid-filled tube.
