Cranial Nerve and Functions

Question 1

Cranial Nerve 1

Answer 1

Olfactory
Description: Conducts olfactory (smell), sensations to brain; only type of nervous tissue to regenerate.

Sensory Function: Olfaction (smell)

Question 2

Pathways of CN 1 Olfactory

Answer 2

Travels through Cribriform foramina of the ethmoid bone and synapses in the olfactory bulbs, which are located in the anterior cranial fossa.

Origin: Receptors (bipolar neurons) in olfactory mucosa of the nasal cavity.

Question 3

What is Cranial Nerve II

Answer 3

Optic Nerve

Question 4

Function of CN II?

Answer 4

Description: Special Sensory Nerve of Vision that is an outgrowth of the brain; known as the brain tract
Sensory Function: Vision

Question 5

Pathway and Origin of CN II Optic Nerve?

Answer 5

Origin: Retina of the eye

Pathway: enters the cranium via optic canal of the Sphenoid bone; left and right optic nerves unite at optic chiasm. Optic tract travels to lateral geniculate nucleus of thalamus.

Question 6

What is CN III?

Answer 6

Oculomotor Nerve

Question 7

Function of Oculomotor Nerve, CN III?

Answer 7

Description: Innervates upper Eyelid muscle abd four of the six extrinsic eye muscles

Somatic Motor Function: Supplies four Extrinsic eye muscles( superior rectus, Inferior rectus, medial rectus, inferior oblique) that move the eyesupplies levator palperbrae superiorismuscle to elevate eyelid

Parasympathetic Motor Function: Innervates sphincter pupillae of iris to make pupil constrict. Contracts cilliary muscles to make lens of eye more spherical

Question 8

Origin and pathway of Oculomotor Nerve CN III

Answer 8

Origin: Oculomotor and Edinger Westphal nuclei within the mesencephalon

Pathway: Leaves Cranium via superior orbital fissure and travels to eye and eyelid

Question 9

Name CN IV?

Answer 9

Trochlear Nerve

Question 10

What is the Somatic Function Of CN IV?

Answer 10

Description: Innervated one extrinsic eye muscle that loops through a pulley shaped ligament

Somatic Function: Supplies one extrinsic muscle (superior Oblique) to move eye inferiorly and laterally

Question 11

What is the Origin and Pathway oF CN IV?

Answer 11

Origin: Trochelar nucleus within the mesencephalon

Pathway: leaves cranium via superior orbital fissure and travels superior oblique

Question 12

What is the cranial Nerve V?

Answer 12

Trigeminal Nerve

Question 13

What is the descriptionof the CN V ?

Answer 13

Description: This nerve cavity consists of three divisions opthalmic, maxillary and mandibular receives sensory impulses from face, oral cavity, nasal cavity and anterior scalp and innervates muscles masstication

Question 14

What are the functions of the Trigerminal Nerve (CN V)?

Answer 14

Motor Function: Innervated muscles of Mastication ( mylohyoid, pterygoids, masseter, temporalis, anterior belly of digastric) tensor tympani. Cell bodies in the nuclei in pons

Sensory Function: Sesnory Stimuli for this nerve are touch, temperature and pain. Bodies in ganglion (trigeminal ganglion), Face _(skin, jaws, tongue,, sinuses, teeth), Opthalmic (V1); Maxillary (v2) and Mandibular (V3)

Question 15

What is CN VI

Answer 15

Abducens Nerve

Question 16

What is the Function of Abducens Nerve (VI)?

Answer 16

Description: Innervates Lateral Rectus eye muscle. which abducts the eye( pulls away laterally)

Somatic Motor Function: Innervates one extrinsic eye muscle ( lateral rectus) for eye of abduction. Nuclei Pons

Question 17

Origin CN VI Abducens Nerve?

Answer 17

Nucleus in pons

Pathway: Leaves Cranium through superior orbital fissure and travels to lateral rectus muscle

Question 18

What is CN VII?

Answer 18

Facial Nerve

Question 19

Function of CN VII Facial Nerve?

Answer 19

Sensory Function: Taste from anterior 2/3 of tongue. Celll bodies in ganglion

Somatic Motor Function (Efferent): The five major motor branches ( temporal, zygomatic, buccal, mandibular, and cervical) (To Zanzibar By Motor Car). Cell bodies in the nucleus in pons . Stylohyoid muscles of facial expression, posterior belly of digastric, buucinator, stapedius.

Parasympathetic : efferent perganglionic, Increases secretions of the lacrimal gland of the eye as well as the submandibuar and sublinguinal salivary gland

Question 20

What is CN VIII

Answer 20

Vestibulocochlear Nerve

Question 21

What is the Function of CN VIII Vestibulocochlear Nerve?

Answer 21

Sensory Function: Afferent sensory only, Innervates spiral Organ of Corti ( Cocholear branch) (Hearing), Innervates saccule and utricle and semicircular ducts (Veistibular branch) , (balance and movement).

Question 22

CN IX?

Answer 22

Glossopharyngeal Nerve

Question 23

What is the Function of Glossopharyngeal Nerve (CN IX)?

Answer 23

Afferent Sensory: Receptors in taste buds and posterior 1/3 of tongue and mucosa. Cell bodies in ganglion

Efferent Motor: Bodies in nucleus in medulla oblongata, terminates stylopharyngeus (Pharynx muscle)

Efferent Preganglionic Paray sympathetic: increases secretion of parotid salivary gland

Question 24

What is Cranial Nerve X?

Answer 24

Vagus Nerve

Question 25

What are the functions of Vagus Nerve (CN X)

Answer 25

Parasympathetic Efferent: Preganglionic, Innervates the visceral smooth muscle, Cardiac muscle and glands of heart, lungs Pharynx, larynx, trachea and most abdominal. Motor Efferent: Cell bodies in nucleus in medulla oblongata. Terminates on muscles of Larynx and Pharynx. Sensory Afferent: Bodies in ganglion, Receptors in mucosa of larynx, alimentary canal to left of colic flexure, lungs and bronchii.

Question 26

What is Cranial Nerve XI?

Answer 26

Accessory Nerve

Question 27

Function of Accessory Nerve (CN XI)

Answer 27

Efferent Motor Only. Bodies in the nucleus in medulla oblongata, Terminates on sternocleidomastoid and Trapezius. Crainial Root: Travels with CN X fibers to pharynx

Question 28

What is Cranial Nerve XII?

Answer 28

Hypoglossal Nerve

Question 29

What is the Function Hypoglossal Nerve (CN XII)

Answer 29

Somatic Motor: Efferent, bodies in nucleus of medulla oblongata, Terminates on muscles of tongue, genioglossus, hyopglossus and styloglossus ( innervates intrinsic and extrinsic tongue muscles) name means under the tongue.