Nervii cranieni

12 Pairs of Cranial Nerves Part of the Peripheral Nervous System Originate from the brain, not the spinal cord Bundles of nerves: sensory and/or

motor(somatic or parasympathetic) Ipsilateral innervation Name includes:

Number Word

4 Classification - Cranial Nerves1. Sensory nerves:

carry somatic sensory information: touch, pressure, vibration, temperature, and pain

2. Special sensory nerves: carry sensations:

smell, sight, hearing, balance3. Motor nerves: – axons of somatic motor neurons

4. Mixed nerves: – mixture of motor and sensory fibers

Summary: Cranial Nerves

Summary: Cranial Nerves

CN I

CN III

CN V

CN VII

CN IX

CN XI

CN II

CN IV

CN VI

CN VIII

CN X

CN XII

Nerv olfactiv

Primary function- special sensory (smell)

Origin receptors of olfactory epithelium

Pathway - olfactory foramina in cribriform plate of ethmoid

Destination - olfactory bulbs Smell Apply odors to each nostril Traumatic anosmia – loss of sense

of smell

• Structures– Olfactory bulbs:located on either

side of crista galli– Olfactory tracts: axons of

postsynaptic neurons, leading to cerebrum

Nerv optic Vision Visual acuity Map field of vision Optic chiasm Sensory only: vision Runs from the retina to the optic chiasm to the thalamus

Nerv optic

Primary function: special sensory (vision)

Origin: retina of eye

Pathway: optic canals of sphenoid

Destination: diencephalon via optic chiasm

• Structures– Optic chiasm: where sensory fibers converge , and cross to

opposite side of brain– Optic tracts: reorganized axons, leading to lateral geniculate

nuclei

Nerv oculomotor Primary function:

motor (eye movements) Origin:

mesencephalon Pathway:

superior orbital fissures of sphenoid

Destination: somatic motor:

superior, inferior, and medial rectus muscles

inferior oblique muscle levator palpebrae superioris muscle

visceral motor: intrinsic eye muscles

Problems: diplopia; uneven eyes

Nerv oculomotor

• Structures• Oculomotor nerve: controls 4 of 6 eye-movement

muscles, delivers autonomic fibers to ciliary ganglion

• Ciliary ganglion: controls intrinsic muscles of iris and lens

Nerv oculomotor

Disorders can result in eye paralysis, diplopia or ptosis.

Nerv trohlear

Primary function: motor (eye movements)

Origin: mesencephalon

Pathway: superior orbital fissure of

sphenoid Destination:

superior oblique muscle

Nervul trigemen Primary function:

mixed (sensory and motor) to face Origins:

ophthalmic branch (sensory): orbital structures nasal cavity skin of forehead, upper eyelid, and eyebrow part of nose

– maxillary branch (sensory): • lower eyelid• upper lip, gums, and teeth• cheek and nose • palate and part of pharynx

– mandibular branch (sensory): • lower gums, teeth, and lips• palate and part of tongue

– mandibular branch (motor): • motor nuclei of pons

Nervul trigemen• Pathways:

– ophthalmic branch: • superior orbital fissure

– maxillary branch: • foramen rotundum

– mandibular branch: • foramen ovale

• Destinations:– sensory nerves: sensory nuclei-pons– motor nerves of mandibular branch:

• muscles of masticationTrigeminal nerves:

largest cranial nerveswith 3 major branches

Semilunar ganglion:contains cell bodies of sensory neurons

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Nervul trigemen Three Branches V1 Ophthalmic

division: sensory V2 Maxillary: sensory V3 Mandibular:

Sensory for the face

Motor (somatic) nerves for chewing

Originates in the pons

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Nervul trigemen

Medical Example: Trigeminal Neuralgia

AKA:Tic Douloureux It is characterized by sudden attacks of

pain that are typically brief, lasting only seconds to two minutes.

These attacks are severe and described as intense, stabbing or electrical shock-like.

Nervul abducens

Primary function: motor (eye movements)

Origin: pons

Pathway: superior orbital fissures of sphenoid

Destination: lateral rectus muscle

Nervul facial Primary function:

mixed (sensory and motor) to face

Origins: sensory: taste receptors on

anterior 2/3 of tongue motor: motor nuclei of pons

• Pathway: – internal acoustic canals to facial canals (stylomastoid

foramina)• Destinations:

– sensory: sensory nuclei of pons– somatic motor: muscles of facial expression– visceral motor: tear and nasal mucous glands, submandibular

and sublingual salivary glands

Originates in the pons

Structures Facial nerve branches:

temporal zygomatic buccal mandibular cervical branchesGeniculate ganglia: hold cell bodies of sensory neurons

Pterygopalatine ganglia: postganglionic fibers innervate

glands (lacrimal, nasal cavity, and pharynx)

Submandibular ganglia: innervate salivary glands

Medical Example: Facial Nerve Palsy

AKA: Bell’s Palsy Causes paralysis of

facial muscles which leads to tearing and drooling.

Loss of taste on one side of tongue.

Nervul glosofaringian

• Primary function: mixed (sensory and motor) to head and neck

• Origins:–sensory:

• posterior 1/3 of tongue• part of pharynx and palate• carotid arteries

–motor: • motor nuclei of medulla oblongata

• Pathway: –jugular foramina between occipital and temporal bones

Figure 14–24

Nervul vestibulocohlear Primary function: special sensory

vestibular branch: balance and equilibrium

cochlear branch: hearing

Origin: receptors of inner ear– internal acoustic canals of temporal bones

• Destination: – vestibular and cochlear nuclei of pons and medulla

oblongata• Structures– Vestibular branch:originates at receptors of vestibule

(balance), connects to vestibular nuclei of pons and medulla oblongata

– Cochlear branch:originates at sensors of cochlea (hearing), connects with cochlear nuclei of pons and medulla oblongata

Nervul vestibulocohlear

Nervul glosofaringian Destinations:

sensory: sensory nuclei of medulla oblongata

somatic motor: nerves involved in swallowing

visceral motor: parotid salivary gland

• Structures– Superior and inferior ganglion:

• sensory neurons of tongue and pharynx– Otic ganglion:

• synapse visceral motor fibers

Nervul vag

Primary function: mixed (sensory and motor) of thorax and abdomen

•Origins:–sensory:

• part of pharynx• auricle and external acoustic

canal• diaphragm• visceral organs of thoracic, and

abdominopelvic cavities–motor:

• motor nuclei in medulla oblongata

Pathway: jugular foramina between occipital and temporal bones

Originates in the medulla

Nervul vag• Destinations:

– sensory: • sensory nuclei and autonomic

centers of medulla oblongata– visceral motor:

• palate, pharynx• digestive, respiratory, and

cardiovascular systems in thoracic and abdominal cavities

• Structures– Vagus nerves:branch and radiate

extensively– Jugular ganglion and inferior nodose

ganglion: hold sensory neurons

Nervul accesor Primary function:

motor to muscles of neck and upper back Origin:

motor nuclei of spinal cord and medulla oblongata

Pathway: jugular foramina between occipital and

temporal bones• Destinations:

– internal branch: • voluntary muscles of palate, pharynx, and

larynx– external branch:

• sternocleidomastoid and trapezius muscles

Structures Spinal root: motor fibers

that originate in anterior gray horns of first 5 cervical segments of spinal cord

Cranial root: motor fibers that originate in medulla oblongata

– Internal branch:joins the vagus nerve

– External branch:controls muscles of neck and back

Nervul accesor

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Medical Example: Accessory Nerve Palsy

Spinal accessory nerve injury can cause drooping shoulder, muscle atrophy, limited elevation of

shoulder, and winged scapula

Nervul hipoglos

Primary function: motor (tongue

movements) Origin:

motor nuclei of medulla oblongata

Pathway: hypoglossal canals of

occipital bone Destination:

muscles of tongue during speech and

swallowing

Originates in the medulla

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Nervul hipoglos

Injury deviates tongue to injured side when protruded.

Reflexe craniene Monosynaptic and polysynaptic reflex

arcs Involve sensory and motor fibers of

cranial nerves Clinically useful to check cranial

nervous system

Examples of Cranial Reflexes

The End