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Published byMalcolm Stokes Modified over 9 years ago
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Cranial Nerves: I & II I. 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 tract II. 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
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Olfactory Nerve (I) – contain the sensory nerves of smell
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Optic Nerve (II) – sensory nerve of vision
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Visual Fields of the Eyes
Fig , p. 584
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Cranial Nerves: III & IV
III. 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
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Oculomotor Nerve (III) – “eye mover” innervates muscles that supply the eyeball
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Trochlear Nerve (IV) – means “pulley” it innervates an extrinsic eye muscle that loops through a pulley-shaped ligament
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Cranial Nerves: V V. 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
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Trigeminal Nerve (V) – supplies sensory information to the face and chewing muscles
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Cranial Nerves: VI & VII
VI. 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
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Abducens (VI) – controls the extrinsic eye muscles that abduct (turn it laterally) the eyeball
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Facial Nerve (VII) – a large nerve that innervates muscles of facial expression
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Cranial Nerves: VIII & IX
VIII.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
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Vestibulococlear Nerve (VIII) – two branches one for hearing, one for balance
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Glossopharangeal (IX) – name means “tongue and pharynx” innervates the tongue and pharynx
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Cranial Nerves: X X. 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) parasympathetic innervation to heart --> decreases heart rate [HR] upper GI tract (stomach, small intestines) --> increases activity Illustration
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Vagus (X) – name means “wanderer”
only cranial nerve to extend beyond the head
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Cranial Nerves: XI & XII
XI. 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) parasympathetic innervation to heart --> decreases heart rate [HR] upper GI tract (stomach, small intestines) --> increases activity Illustration
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Accessory Nerve (XI) – joins to help the vagus nerve, innervates neck musculature
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Hypoglossal (XII) – innervates some tongue- moving muscles
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Cranial Nerves: I - XII Fig. 13.4, p. 484
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