Cranial Nerves: I & III.Olfactory -- sensory (smell)

° nerves embedded in nasal mucosa° enter cranial cavity through olfactory foramina in

cribriform plate (ethmoid bone)° synapse with other neurons in olfactory bulb

impulse continues through olfactory tractII. Optic -- sensory (sight)

° nerves extend from retina° enter cranial cavity through optic foramina

(sphenoid bone)° medial fibers cross at optic chiasma (sits in

chiasmatic groove of sphenoid bone)° fibers continue as optic tracts Illustration

Olfactory Nerve (I) – contain the sensory nerves of smell

Optic Nerve (II) – sensory nerve of vision

Fig. 16.12, p. 584

Visual Fields of the Eyes

Cranial Nerves: III & IVIII. Oculomotor – motor

° extrinsic muscles of eye except lateral rectus and superior oblique (eye movement)

° intrinsic smooth muscle of iris (constriction in response to brightness) and lens (controls shape for focusing)

IV. Trochlear – motor ° superior oblique muscle of eye

Illustration

Oculomotor Nerve (III) – “eye mover” innervates

muscles that supply the eyeball

Trochlear Nerve (IV) – means “pulley” it innervates an extrinsic eye muscle that loops through a pulley-shaped ligament

Cranial Nerves: VV. Trigeminal – mixed; largest cranial nerve, major

sensory nerve serving face (skin, mucosae of mouth, surface of eyes), also important motor nerve (chewing)° mandibular division – motor to chewing muscles;

sensory from anterior tongue and lower teeth- mandibular division exits/enters through foramen

ovale° ophthalmic and maxillary divisions -- sensory

- ophthalmic division from area around eye and forehead enters through superior orbital fissure

- maxillary division from area around nose, cheeks, upper jaw enters through foramen rotundum

Illustration

Trigeminal Nerve (V) – supplies sensory

information to the face and chewing muscles

Cranial Nerves: VI & VIIVI. Abducens – motor

° lateral rectus muscle of eye° enters/exits cranial cavity through superior

orbital fissure

VII. Facial – mixed° sensory from taste buds on tongue° motor (ANS) to salivary and lacrimal glands° motor (somatic) to muscles of facial expression° enters/exits through stylomastoid foramen

Illustration

Abducens (VI) – controls the extrinsic eye muscles that abduct (turn it laterally) the eyeball

Facial Nerve (VII) – a large nerve that innervates muscles of facial expression

Cranial Nerves: VIII & IXVIII.Vestibulocochlear – sensory

° hearing and balance from inner ear° enters through internal acoustic meatus

IX. Glossopharyngeal -- mixed ° motor to pharyngeal muscles and salivary

glands° sensory from taste buds° exits/enters through jugular foramen (border of

temporal and occipital bones)

Illustration

Vestibulococlear Nerve (VIII) – two branches one

for hearing, one for balance

Glossopharangeal (IX) – name means “tongue and pharynx” innervates the tongue and pharynx

Cranial Nerves: XX.Vagus -- mixed

° motor (somatic) to pharynx and larynx for swallowing and speaking

° motor (ANS: parasympathetic) innervation to heart, lungs and abdominal viscera

° sensory info from thoracic and abdominal viscera

° exits/enters through jugular foramen (border of temporal and occipital bones)

Illustration

Vagus (X) – name means “wanderer”

only cranial nerve to extend beyond the head

Cranial Nerves: XI & XIIXI. Accessory -- motor

° muscles of neck° enters/exits through jugular foramen (border

of temporal and occipital bones)

XII. Hypoglossal – motor° muscles of tongue (chewing, swallowing

and speech)° enters/exits through hypoglossal canal

(superior to occipital condyles of occipital bone)

Illustration

Accessory Nerve (XI) – joins to help the vagus

nerve, innervates neck musculature

Hypoglossal (XII) – innervates some tongue-

moving muscles

Cranial Nerves: I - XII

Fig. 13.4, p. 484