Cranial Nerves

Question 1

What is a bundle of axons travelling within the CNS known as

Answer 1

A fibre tract or fasciculus

Question 2

What is a bundle of axons travelling within PNS known as

Answer 2

‘Nerve’ or peripheral nerve

Question 3

How many cranial nerves are there

Answer 3

12 pairs

Question 4

Which bones make up the neurocranium

Answer 4

Frontal, ethmoid, sphenoid and occipital bones, 2 temporal bones, 2 parietal bones
Upper and back part of the skull

Question 5

What is the viscerocranium

Answer 5

Collection of bones that make up the face skeleton

Question 6

What are the 12 cranial nerves

Answer 6

I.Olfactory, sensory
II. Optic, sensory
III.Oculomotor, motor
IV.Trochlear, motor
V. Trigeminal, both
VI.Abducens, motor
VII.Facial, both
VIII.Vestibulocochlear, sensory
IX.Glossopharyngeal, both
X.Vagus, both
XI.Accessory, motor
XII.Hypoglossal, motor

Question 7

Olfactory nerve

Answer 7

Sense of smell; allows us to identify and distinguish different smells
Cribriform plate
Supplies nasal mucosa

Question 8

Optic nerve

Answer 8

Part of visual pathway
Carries sensation of vision from retina of eye to the brain
Optic canal
Converges toward anterior part of hypothalamus
Optic nerves cross over to form the optic chiasm

Question 9

Oculomotor nerve

Answer 9

Allows elevation, Adduction and depression of the eye
Constricts pupil, parasympathetic innervation
Superior orbital fissure SOF
Supplies extrinsic muscles that move eye and intrinsic muscles that control pupil constriction and lens accommodation

Question 10

Trochlear nerve

Answer 10

Smallest cranial nerve
Enables movement in eye’s superior oblique muscle
Innervates a single muscle
Sciatic foramina
Supplies superior oblique muscle

Question 11

Trigeminal nerve

Answer 11

3 branches
V1- opthalmic -supply’s sensory innervation to structures of eye including cornea, ciliary body, lacrimal gland and conjunctiva. Superior orbital fissure
V2- maxillary- sensation to middle region of the face incl. teeth, palate, gums. Foramen rotundum
V3- mandibular- mixed nerve so contains both motor and sensory fibres, transmits sensory info from lower 3rd of face and motor innervation of masticatory muscles. Foramen ovale

Question 12

What does the Trigeminal nerve supply

Answer 12

V1- scalp, forehead, upper eye and eyelid, medial portion of nose
V2-dura matter of middle cranial fossa, mucosa of nose, teeth, upper jaw, lower eyelid, cheek, upper lid
V3-sensory: jaw, lateral regions of cheek and temples, lower mouth incl. teeth, gums,tongue. Motor: temporalis, masseter and pterygoids

Question 13

Abducens nerve

Answer 13

Innervate the ipsilateral lateral rectus muscle. Involved in abduction of eye
Motor nerve control movement of eyeball
Superior orbital fissure
Lateral rectus muscle of eye

Question 14

Facial nerve

Answer 14

Responsible for facial expressions. Allows taste from anterior 2/3 of tongue. Innervate salivary glands
Stylomastoid foramen
Muscles of facial expression and the stapedius muscle. Parasympathetic fibres go to ganglia that supply glands in oral cavity and lacrimal gland

Question 15

Vestibulocochlear nerve

Answer 15

Brings sound and information about one’s position &movement into the brain
Internal acoustic meatus
Supplies the Vestibular organ and cochlea

Question 16

Glossopharyngeal nerve

Answer 16

Mixed nerve that consists of motor and sensory fibres
Provides motor innervation to stylopharyngeus muscle which is responsible for elevating type pharynx and larynx
Jugular foramen
Supplies the stylopharyngeus muscle and superior pharyngeal constrictor muscle

Question 17

Vagus nerve

Answer 17

General and special sensation to laryngopharynx and epiglottis. Parasympathetic innervation and visceral sensation from thorax and abdomen. Motor innervation of muscles in pharynx, larynx and 1 tongue muscle
Jugular foramen
Supplies the thorax and abdominal viscera. Back of oral cavity, larynx and pharynx. Palatoglossus muscle

Question 18

Accessory nerve

Answer 18

Carries motor innervation to pharyngeal constrictors, larynx and muscles of soft palate
Controls movement of certain neck muscles
Jugular foramen
Supplies the sternocleidomastoid and trapezius muscles

Question 19

Hypoglossal nerve

Answer 19

Responsible for change in shape movement of the tongue
Hypoglossal canal
Innervates all intrinsic muscles and all but one of extrinsic muscles of tongue
Controls hyoglossus, intrinsic, genioglossus, styloglossus muscles

Question 20

A puff of air to the cornea of the eye to induce a blink reflex can be used clinically to test cranial nerve function what nerve is most involved in initiating the reflex

Answer 20

Ophthalmic division of the Trigeminal nerve