Cranial Nerves Flashcards
What is the function of CN I?
If CN I is damaged, what can a patient experience?
OLFACTORY NERVE
FUNCTION: SENSORY
Carry afferent impulses for sense of smell.
If damaged: Patient may lose partial or total loss of smell, a condition known as anosmia
What is the function of CN II?
If damaged, what can a patient experience?
OPTIC NERVE
Function: SENSORY
carry afferent impulses for vision
If damaged: Damage to optic nerve results in blindness in eye served by nerve; damage to visual pathway beyond the optic chiasma results in partial visual losses.
What is the function of CN III?
If damaged, what can a patient experience?
OCCULOMOTOR
FUNCTION: SENSORY, MOTOR & PARASYMPATHETHIC
- Proprioceptive afferents from 4 extrinsic eye muscles to midbrain.
- efferents to 4 of 6 extrinsic eye muscles (inferior oblique, superior rectus, inferior rectus & medial rectus)
- pupil constriction & lens thickening
If damaged: eye cannot be moved up, down or inward. At rest, eye rotates laterally, upper eyelid droops, double vision & trouble focusing on close objects.
What is the function of CN V?
If damaged, what can a patient experience?
TROCHLEAR NERVE
FUNCTION: SENSORY & MOTOR
- Proprioceptive afferents from superior oblique.
- innervates superior oblique muscles of eye.
If damaged: Double vision & reduced ability to rotate eye inferolaterally.
What is the function of CN V?
If damaged, what can a patient experience?
TRIGEMINAL NERVE
- OPHTHALMIC BRANCH V1: SENSORY
Impulses from upper eyelid, eye surface, tear glands, nose, scalp & forehead.
- MAXILLARY BRANCH V2: SENSORY
Impulses from upper teeth, upper gum & lip, palate & skin of face.
- MANDIBULAR BRANCH V3: SENSORY & MOTOR
Impulses from lower teeth, lower gum & lip, skin of jaw & part of scalp.
fibers to muscles of mastication.
If damaged: Trigeminal neuralgia
What is the function of CN VI?
If damaged what can the patient experience?
ABDUCENS NERVE
FUNCTION: SENSORY & MOTOR
- Proprioceptive afferents from lateral rectus muscle to brain.
- fibers innervating lateral rectus muscle of eyes.
If damaged: eye cannot be moved laterally
What is the function of CN VII?
If damaged what can the patient experience?
FACIAL NERVE
FUNCTION: SENSORY, MOTOR, PARASYMPATHETIC
- taste impulses from anterior 2/3 of tongue
- impulses to muscles of facial expression
- innervation of salivary glands (submandibular & sublingual)
If damaged: Bell’s Palsy
What is the function of CN VIII?
If damaged what can the patient experience?
VESTIBULOCOCHLEAR NERVE
FUNCTION: SENSORY
- COCHLEAR BRANCH: transmit afferent impulses for sense of hearing
- VESTIBULAR BRANCH: transmit afferent impulses for sense of equilibrium
If damaged to cochlear branch: loss of hearing
If damaged to vestibular branch: dizziness, rapid involuntary eye movements, loss of balance, nausea & vomiting.
What is the function of CN IX?
If damaged what can the patient experience?
GLOSSOPHARYNGEAL NERVE
FUNCTIONS: SENSORY, MOTOR & PARASYMPATHETIC
- conduct taste from posterior 1/3 of tongue, general sensory impulses (touch, pain & temperature) from tongue, tonsils & Eustachian tube to medulla
- innervates muscles of pharynx for swallowing & some motor to tongue
- innervation to parotid salivary gland
If damaged: impairs swallowing & taste
What is the function of CN X?
If damaged what can the patient experience?
VAGUS NERVE
FUNCTIONS: SENSORY, MOTOR & PARASYMPATHETIC
- general sensory from tongue & pharynx; sensory back from abdominal viscera
- carry fibers to muscles of pharynx & larynx
- innervation of heart, lungs & abdominal viscera
If damaged: hoarseness or loss of voice, difficulty swallowing, impaired digestive motility. If both vagus nerves are damaged = DEATH!
What is the function of CN XI?
If damaged, what can a patient experience?
SPINAL ACCESSORY NERVE
FUNCTION: SENSORY & MOTOR
- proprioceptive afferents from sternocleidomastoid & trapezius
- innervation of muscles in the shoulder & neck (sternocleidomastoid & trapezius), pharynx & larynx
If damaged: shrugging of shoulder becomes difficult
What is the function of CN XII?
If damaged, what can a patient experience?
HYPOGLOSSAL NERVE
FUNCTION: SENSORY & MOTOR
- proprioceptive afferents back from muscles of tongue
- innervation to muscles involved in tongue movement
If damaged: difficulties in speech & swallowing
