Exam 3: Cranial Nerves

Question 1

Cranial Nerves

Answer 1

• 12 pairs
• directly off brain
• can carry any of the following (or combos thereof) sensory axons, somatic motor axons (voluntary) parasympathetic motor axons (ANS, involuntary)

Question 2

CN I Olfactory

Answer 2

• sensory axons only
• function: smell
• olfactory nerves synapse (exchange a nerve impulse with another neuron) in olfactory bulb
• olfactory bulbs connect to olfactory tracts
• test for nerve damage: test smell

Question 3

CN II Optic

Answer 3

• sensory axons only
• function vision
• optic nerves travel to optic chiasm
• test for nerve damage: test vision

Question 4

Optic Chiasm

Answer 4

• some axons from left and right optic nerves cross here

- makes it so each eye can transmit nerve impulses to both sides of the brain

Question 5

Optic Tracts

Answer 5

-carry info from BOTH eyes to ONE side of brain

Question 6

CN III Oculomotor

Answer 6

• somatic motor and parasympathetic motor axons
• functions: somatic motor supplies 4 eye muscles (superior inferior and medial rectus and inferior oblique) and a muscle in the upper eyelid (levator palpebrae superioris)
• test for nerve damage: does pupil constrict? does person’s upper eyelid droop? does person have diplopia (double vision)

Question 7

CN IV Trochlear

Answer 7

• somatic motor axons only
• function: supplies superior oblique
• test for nerve damage: diplopia?

Question 8

CN V Trigeminal

Answer 8

• somatic motor and sensory axons
• functions: somatic motor-muscles of mastication (masseter temporalis medial and lateral pterygoid) sensory-anterior part of scalp, entire face, nasal cavity, oral cavity, teeth, cranial meninges-responsible for brain freeze
• test for nerve damage: move jaw/chew, touch face

Question 9

CN VI Abducens

Answer 9

• innervates muscle that abducts eye
• somatic motor axons only
• function: supplies lateral rectus
• test for nerve damage: have patient move eye laterally, diplopia?

Question 10

CN VII Facial

Answer 10

• controls muscles of face
• somatic motor, sensory, and parasympathetic motor axons
• functions: somatic motor-muscles of facial expression, sensory-taste on anterior 2/3 of tongue, parasympathetic motor-stimulates secretion of lacrimal gland and most salivary glands
• test for nerve damage: smile, frown, wink. taste something. dry mouth? do eyes tear when ammonia near eye?

Question 11

CN VIII Vestibulocchlear

Answer 11

• sensory axons only
• functions: hearing and equilibrium
• test for nerve damage: hearing loss or deafness? is person experiencing vertigo, lack of balance, dizziness, nausea/vomiting?

Question 12

CN IX Glossopharyngeal

Answer 12

-contains somatic motor, sensory, and parasympathetic motor axons
-sore throat pain transmits via this nerve
-functions: somatic motor to one pharynx (throat) muscle. sensory-part of pharynx, touch and TASTE sensation on posterior 1/3 of tongue. parasympathetic motor-stimulates secretion to parotid (salivary) gland
test for nerve damage: cant really isolate motor function so test other two. dry mouth? taste on back of tongue

Question 13

CN X Vagus

Answer 13

• somatic motor and parasympathetic motor axons
• functions: somatic motor-supplies most pharynx (swallowing) muscles and larynx (voice box) muscles. parasympathetic motor-supply muscel in heart, lungs, most abdominal organs.
• test for nerve damage: difficulty swallowing? have hoarse voice, permanent loss of voice, monotone voice?

Question 14

CN XI Accessory

Answer 14

• somatic motor axons only
• functions: innervates trapezius and sternocleidomastoid
• test for nerve damage: shrug shoulders, turn head and flex neck

Question 15

CN XII Hypoglossal

Answer 15

• somatic motor axons only
• functions: supplies intrinsic tongue muscles and most extrinsic tongue muscles
• test for nerve damage: stick out tongue (tongue deviates to one side indicates nerve damage)

Question 16

Pneumonic

Answer 16

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