Ch. 14: Cranial Nerves Flashcards
(44 cards)
cranial nerves involved in speaking
V, VII, X, XII
- X (larynx, soft palate)
- VII (lips)
- V (Jaw)
- XII (tongue)
Stages of Swallowing
- Oral (V, VII, XII)
- Laryngeal/Pharyngeal (IX, X)
- Esophageal (X)
CN X dysfunction
- hard to speak
- hoarse voice
- asymmetric elevation of soft palate
- loss efferent gag
- loss efferent swallow
- poor digestion
CN I Function
- Olfactory
- Sensory=smell
(olfactory nerves and olfactory tract)
CN II Function
- Optic
- Sensory=vision
conscious vision/reflex (orient head–sup colliculi)
3 Functions of CN
- motor innervation
- somatosensory and special sensory innervation
- parasympathetic innervation
CN I Dysfunction
- unable to smell
- linked with parkinson’s and alzheimers (neurodegeneration)
CN II Dysfunction
- blindness
- loss of visual field
-Disrupted pupillary light reflex
CN IV function
- Trochlear
- (midbrain)
- move eye medially and down toward tip of nose
Medial Longitudinal Fissure
- interconnects CN III, IV, VI, vestiular nuclei and CN XI in brainstem
- wiring bundle connect eye CN to each side to allow conjugate eye movement
3 Eye Reflexes
- Pupillary Light Reflex
- Consensual Light Reflex
- Accommodation Reflex
CN VI Function
- Abducens
- (border of pons/medulla)
- move eye toward ipsilateral ear
Parasympathetic Innervation to pupil and lens
- CN III
- innervates pupillary sphincter and ciliary Mm
- constricts pupil for (near vision)
- increases curvature of lens (for near vision)
Pupillary Light Reflex
- unconscious
- Stimulus: light in one eye (CN II)
- Response: constrict pupil (CN III)
Consensual Light Reflex
- reflex only
- Stimulus: light in one eye (CN II)
- Response: constriction of both pupils (CN III)
CN III Function
- occulomotor
- (Midbrain)
- sup rectus, med rectus, inf rectus, inf oblique
-move eye up, down and adduction
Ptosis
- eyelid droops
- (sign of Horner’s Syndrome)
- CN III dysfunction
Accommodation Reflex
- Consciously driven by visual cortex
- Input: object close to face
- Response: pupils constrict, eyes converge, lens more convex
(opposite with object far from face)
CN III dysfunction
- Ptosis
- affected eye looks down and out
- diplopia
- can’t move eye med, up or down
- dilation of pupil
- decreased pupillary light reflex
- decreased consensual light reflex
- decreased constriction of pupil for near objects
CN IV Dysfunction
- can’t look down and inward
- Extorsion due to unopposed action of inf oblique
- (can result in tilted head to compensate for rotated eye)
CN VI Dysfunction
- can’t abd eye
- resting position of eye drifts medially
Efferent CN V
- Mm of mastication
- muscles that move jaw
Medial Longitudinal Fasciculus Dysfunction
- no conjugate eye movement
- CN still work but signal from one side doesn’t reach other
Jaw Jerk Reflex
Stim: quick stretch to mastication Mm
Response: jaw Mm try to close mouth