Cranial Nerves Flashcards
cranial nerves overview
- 12 pairs
- attached to brain
- can be sensory, motor, or mixed
- control head/neck/ face (except vagus nerve)
sensory nerves
long dendrites of only sensory neurons
motor nerves
long axons of only motor neurons
mixed nerves
long dendrites and long axons
special sensory nerves
carry information for sight, smell, hearing, or balance
CN I
olfactory nerve
- special sensory nerve –> sense of smell
- originates in olfactory epithelium
- terminates in olfactory bulbs
- attached to cerebrum (unlike all others, which are attached to brain stem)
CN II
optic nerve
- special sensory nerve –> sense of sight
- originates in retina of each eye, crosses at optic chiasm
- synapses in thalamus, which sends info to visual cortex of occipital lobe
CN III
oculomotor nerve
- motor nerve –> eye movement + pupil dilation
- somatic motor movement (muscles)
- visceral motor movement (pupils)
purpose of pupil dilation
controls the amount of light let into the eye
CN IV
trochlear nerve
- motor nerve: innervates superior oblique muscle –> eye movement
- somatic motor movement (muscles)
CN V
trigeminal nerve
- mixed nerve –> mastication, sensation of face/nose/mouth
- 3 branches
opthalmic branch of trigeminal nerve
- entirely sensory
- receives info from skin around forehead, eyebrows, upper part of nose
maxillary branch of trigeminal nerve
- entirely sensory
- receives info from lower eyelids, upper lip/gums, part of pharynx
mandibulary branch of trigeminal nerve
- sensory –> receives info from lower lip/gums, teeth, tongue (except taste)
- motor –> innervates muscles of mastication
CN VI
abducens nerve
- motor nerve –> abduction of eye (outward/lateral mvmt)
- innervates lateral rectus muscles
CN VII
facial nerve
- mixed nerve
- responsible for facial expressions, sensation of tongue, taste (anterior tongue)
- visceral motor functions –> controls tear glands, nasal mucous glands
CN VIII
vestibulocochlear nerve
- special sensory nerve –> hearing + balance
- 2 branches
- travels via internal acoustic meatus in temporal bone
vestibular branch of vestibulocochlear nerve
responsible for balance and equilibrium
cochlear branch of vestibulocochlear nerve
responsible for sense of hearing
CN IX
glossopharyngeal nerve
- mixed nerve
- motor –> innervates swallowing muscles
- sensory –> taste (posterior tongue)
- visceral motor functions –> controls parotid salivary glands
CN X
vagus nerve
- mixed nerve
- responsible for digestion, heart rt regulation, sensation of digestive tract
- spreads out widely in abdomen
CN XI
accessory nerve
- motor nerve
- controls muscles involved in head rotation, mvmt of upper shoulders
CN XII
hypoglossal nerve
- motor nerve
- responsible for voluntary tongue movements
