Cranial Nerves Flashcards
(28 cards)
Which cranial nerves are not true nerves?
CN 1 & 11
they are fiber tracts
CN 1
olfactory (smell)
- odor –> sensory receptors –> detected by olfactory bulb –> travel through olfactory tract –> terminate in anterior perforated substance –> intimate connections with entorhinal cortex, amygdala, hippocampus, and other parts of the limbic system
What parts of the brain are stimulated when you smell something?
- entorhinal cortex (memory, navigation, perception of time)
- amygdala (emotions; fear)
- hippocampus (memories)
- other parts of the limbic system
anosmia
partial or full loss of smell
- colds, rhinitis, tumors
hyperosmia
overwhelming sensitivity to smells
- hysterics, cocaine addicts
parosmia
distorted sense of smell
- olfactory hallucinations, hysterics, seizures, schizophrenia, uncinate gyrus lesions
cacosmia
unpleasant odors
- decomposition of tissue
CN II
optic
- visual acuity, visual fields, fundi exam
How does light get processed in the eyes?
eyeball focuses light –> stimulates retina –> signals transmitted via optic nerve, chiasm, and tract to lateral geniculate nucleus (thalamus) –> impulses travel via optic radiations –> termination in the primary visual cortex (calcarine)
Lesion at the right optic nerve
anopsia of the right eye
- full right sided blindness
Lesion at the optic chiasm
bitemporal hemianopia
- temporal fields affected –> can’t cross chiasm
Lesion at right optic tract (lateral geniculate)
right homonymous hemianopia
- temporal retina of L eye + nasal visual field of R eye affected
Name all 12 cranial nerves
I - Olfactory
II - Optic
III - Oculomotor
IV - Trochlear
V - Trigeminal
VI - Abducens
VII - Facial
VIII - Vestibulocochlear
IX - Glossopharyngeal
X - Vagus
XI - Accessory
XII - Hypoglossal
Three branches of the trigeminal nerve
V1 = ophthalmic
V2 = maxillary
V3 = mandibular
CN III
oculomotor
- pupil diameter/response, accommodation
- “all the rest are 3”
- injury - dilated pupil + ptosis (fixed and dilated)
CN IV
trochlear
- SO4
CN V
trigeminal
- masseter muscle
- corneal reflex
CN VI
abducens
- LR6
CN VII
facial
- asymmetry of the face
- CVA or Bell’s Palsy
- injury = facial droop, dry eyes, dry mouth
Bell’s Palsy vs. CVA
Bell’s Palsy = unilateral facial paralysis
CVA = forehead can still wrinkle, the rest paralyzed
CN VIII
auditory
- whisper test, Weber, Rinne
- 256 Hz tuning fork
CN IX
glossopharyngeal
- voice, gag reflex, UVULA DEVIATION, sensory posterior 1/3 tongue, auditory tube, pharynx
CN X
vagus
- termed “wanderer” because it is the LONGEST cranial nerve
- gag reflex, voice, uvula deviation, sensory/motor for larynx/pharynx
- palatoglossus (tongue control)
CN XI
accessory
- muscles of larynx + pharynx
- muscles of traps + SCM
- shrug shoulders, push head laterally against hand
