Cranial Nerves

Question 1

Olfactory Nerve (CN I)

Answer 1

Conducts smell to the brain-Only nervous tissue to regenerate.

Sensory

Origin: Receptors in mucosa in nasal cavity

Pathway: Travels through cribriform foramina and olfactory bulbs in anterior cranial fossa, Olfactory tract to olfactory cortex.

Question 2

Optic Nerve (CN II)

Answer 2

Outgrowth of optic tract

Sensory: Vision

Origin: Retina of eye

Pathway: Enters cranium via optic canal, Cross at optic chiasm, Travels to lateral thalamus, Info forwarded to occipital lobe

Question 3

Oculomotor Nerve (CN III)

Answer 3

Innervates upper eyelid muscles and 4/6 eccentric muscles

Motor

Somatic: Supplies superior rectus, inferior rectus, medial rectus, and inferior oblique muscles that move eye. Supplies levator palapbrae superioris that elevates eyelid.

Parasympathetic: Innervates sphincter pupillae muscle (makes pupil contract) and ciliary muscles that make lens more spherical

Origin: Oculomotor and Edinger nuclei in midbrain

Pathway: Leaves cranium via superior orbital fissure.

Question 4

Trochlear Nerve (CN IV)

Answer 4

Motor

Supplies one extinctric muscle (superior oblique) to move eye inferiorly and laterally

Origin: Trochlear nucleus within midbrain

Pathway: Leaves via superior orbital fissure and goes to superior oblique muscle

Question 5

Trigeminal Nerve (CN V)

Answer 5

Both

3 Branches
V1- Opthalmic (sensory)
V2- maxillary (sensory)
V3- mandibular-muscles of mastication

origin: Pons

Goes through superior orbital fissure, foramen rotundum and ovale

Question 6

Abducens (CN VI)

Answer 6

motor

innervates lateral rectus muscle

origin- anducens nuclei in pons

goes through superior orbital fissure

Question 7

Facial (CN VII)

Answer 7

both

sensory- taste from anterior 2/3 tongue
parasympathetic- secretions in lacrimal gland and sublingual glands
somatic- muscles of facial expression

origin- nuclei within pons

Question 8

Vestibutrochlear (VIII)

Answer 8

conducts equillibrium and auditory sensations to nerves

sensory

origin: cochlea/ vestibule of inner ear

through internal acoustic meatus

Question 9

Glossopharyngeal Nerve (IX)

Answer 9

Both

Sensory- sensation and taste in posterior tongue
somatic- innervates pharynx muscle
parasympathetic- secretes parotid salivary gland

origin: taste buds of posterior tongue

jugular foramen to pons

Question 10

Vegus Nerve (CN X)

Answer 10

sensory- senses abdominal organs
motor- speech
automonic- motor function or organs

both

jugular foramen

Question 11

Accessory Nerve (XI)

Answer 11

motor- innervates traps and sternocleidomastoid muscles

origin: motor nuclei in medulla oblongata; motor nuclei in spinal cord

through foramen magnum and jugular foramen