Lecture 8 - Cranial nerves Flashcards by Marilou Gélinas

C I name + function

Olfactory nerve

Function: special sensory (or visceral afferent - smell)

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C II name + function

Optic nerve

Function: special sensory (somatic afferent - vision)

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Content of left optic tract

Medial fibers from right eye
+
Lateral fibers from left eye

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Content of right optic tract

Medial fibers from left eye
+
Lateral fibers from right eye

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In the optic nerve, ____ fibers cross-over but ____ stay on the same side

medial, lateral

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C III name + function

Occulomotor (“eye mover”)

Function: mainly motor

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C III - occulomotor innervates what? (5)

Superior, inferior and medial rectus muscles
Inferior oblique muscle
Levator palpabrae muscle
Ciliary bodies (muscles) of the lens
Iris

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Where the nerve (CIII) divides into the superior and inferior divisions

Within the superior orbital fissure

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C IV name + function + origin

Trochlear nerve
Function: mainly motor
Originates from the superiolateral aspect of the pons

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T or F: The trochlear nerve passes through the inferior orbital fissure

FALSE, superior orbital fissure

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Injury to CIV effect

Inhibits the eyeball from turning out and down (inferolaterally)
= Diplopoa

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Only cranial nerve to emerge dorsally from the brainstem

CN IV - trochlear

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C V name + function + location

Trigeminal nerve
Function: will be discussed for each division of CN V
Location: at the side of the pons

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Largest cranial nerve

CV - trigeminal

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The first two divisions of CN V are ____

purely sensory

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Name the 3 divisions of the CN V

Ophthalmic division (C V1)
Maxillary division (C V2)
Mandibular division (C V3)

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Ophthalmic (C V1) supplies ? (9)

Eyeball, conjunctiva, lacrimal sac and gland, nasal mucosa, frontal sinus, external nose, upper eyelid, forehead and scalp

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C V1 passes where

Through the superior orbital fissure

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C V2 passes where

Through the foramen rotundum

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Maxillary division (C V2) relays sensation from?

From the skin of the face over the maxilla including the upper lip, maxillary teeth, nasal mucosa, maxillary sinuses and palate

The third division of the CN V is both a ____ and ____ nerve

Motor, sensory

C V3 passes where

Through the foramen ovale

Motor component of the CN V3

Muscles of mastication (Masseter, temporalis, medial & lateral pterygoid)

Sensory component of the CN V3

Skin over the mandible, lower lip and side of head, mandibular teeth, mucosa of the mouth and the posterior two thirds of the tongue

CN VI name + function + innervation

Abducens nerve Function: mainly motor Innervates the lateral rectus muscle

CN VI passes where

Through the superior orbital fissure

CN VII name + function

Facial nerve | Function: mixed, primarily a motor nerve, but also carries special sensory fibers (taste)

CN VII passes where

Emerges between the pons and medulla on the brain Exits the skull through the internal acoustic meatus, facial canal, and STYLOMASTOID FORAMEN Passes through the parotid gland

Facial nerves supplies (7 groups)

Muscles of facial expression Taste to anterior two thirds of the tongue Parasympathetic innervation to the submandibular, sublingual and lacrimal glands and mucous glands of the soft palate, nose and paranasal sinuses

CN VIII name + function + location

Vestibulocochlear nerve Function: mixed (mainly sensory) Located in the petrous portion of the temporal bone at the internal acoustic meatus

Nerve that DOES NOT exit the skull

Vestibulocochlear - CN VII

2 divisions of CN VIII

1. Vestibular (equilibrium) | 2. Cochlear (hearing)

CN IX name + function

Glossopharyngeal nerve | Function: mixed

Responsibility of CN IX

Conveying taste from the posterior one third of the tongue

CN IX supplies (7 things)

Sensory innervation to the pharyngeal mucosa, palatine tonsil, posterior one third of tongue, eustachian tube, middle ear, carotid sinus and carotid body

Only muscle innervated by CN IX

Stylopharygeus muscle

CN IX passes where

Through the jugular foramen to exit the skull

CN X name + function

Vagus nerve | Function: mixed

Responsibility of vagus nerve

Sensation from the inferior pharynx, larynx and thoracic & abdominal viscera

CN X innervates what

Muscles of the soft palate, pharynx, intrinsic laryngeal muscles and palatoglossus muscles of the tongue

Why is the vagus nerve called "the wanderer"

Due to its extensive innervation throughout the body

CN X exits where

Exits the skull at the medulla oblongata with CN IX at the jugular foramen

CN XI name + function + origin

Accessory nerve Function: mainly motor Originates from the medulla oblongata and spinal cord

Responsibility of CN XI (innervation)

Motor innervation of the sternocleidomastoid and trapezius muscles

CN XI exits where

Jugular foramen

CN XII name + function + origin

Hypoglossal nerve Function: mainly motor Originates from the medulla oblongata

CN XII exits where

Through the hypoglossal canal

CN XII supplies

All of the muscles of the tongue except palatoglossus (supplied by CN X)

What is the helpful mnemonic to remember the function of the cranial nerves

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