Cranial nerves

Question 1

Olfactory nerve (I)

Answer 1

Purely sensory: transmit sense of smell from the nasal cavity

Question 2

Optic nerve (II)

Answer 2

Sensory: Transmits visual signals from the retina of the eye to the brain.[3

Question 3

Oculomotor nerve (III)

Answer 3

Mainly motor:

• Innervates most extrinisic eye muscles
• Also innervates the muscles that constrict the pupil (muscles of the iris) and ciliary body

Question 4

Trochlear nerve

Answer 4

CN 4:

Only motor nerve:

• innervates the superior oblique muscle of the eye
• Dysfunction causes loss of downward and inward movement of the eye

Question 5

Trigeminal nerve

Answer 5

CN 5:

• sensory fiber: provides sensation to the face & head
• Motor fiber: muscles of mastication: biting and chewing

Question 6

Abducens nerve (VI)

Answer 6

Mainly motor

• innervates the lateral rectus muscle of the eye
• Dysfunction causes the inability to abduct the eye

Question 7

Facial nerve (VII)

Answer 7

Motor Innervatation to the muscles of facial expression

Also receives the special sense of taste from the anterior 2/3 of the tongue and provides secretomotorinnervationto the salivary glands(except parotid) and the lacrimal gland.

Question 8

Glossopharyngeal nerve (IX) (9)

Answer 8

Cranial nerve 9:

Sensory:

• Taste buds on posterior 1/3 of tongue
• Receptors in pharynx and carotid sinus
• Motor:
• muscles of pharynx;
• Provides PNS control to paratid gland

Question 9

Vestibulocochlear nerve (VIII)

Answer 9

Mostly sensory: provides information regarding headmovement, rotations and body’s center of gravity that’s key for balance and sensory information regarding soundwaves for hearing

Vestibular nerve: carries impulse for equilibrium

Cochlear nerve: carries impulses for hearing

(cochlea, vestibule, and semicircular canals of inner ear)

Question 10

Vagus nerve (X)

Answer 10

Cranial nerve 10:

Innervates the lungs, heart, and GI tract (abdominal organs)

Motor: muscles of pharynx and larynx; throacic and abdominal organs

Sensory: taste buds on tongue and pharynx;

Question 11

Accessory nerve (XI)

Answer 11

(CN XI)

Mainly motor:

Controls the sternocleidomastoidand trapezius muscles, and overlaps with functions of the vagus nerve. Symptoms of damage: inability to shrug, weak head movement.

Innervates the muscles of larynx, pharynx, soft palate, shoulder and neck

Question 12

Hypoglossal nerve (XII)

Answer 12

Provides motor innervation to the muscles of the tongue (except for the palatoglossal muscle, which is innervated by the vagus nerve) and other glossal muscles.

Important for swallowing (bolus formation) and speech articulation.