Cranial Nerve Video Flashcards
What are The Olfactory Nerves?
- Arise from the olfactory receptor cells of nasal cavity
- Pass through the cribriform plate of the ethmoid bone
- Fibers synapse in the olfactory bulbs
- Pathway terminates in the primary olfactory cortex
- Purely sensory (olfactory)
function
What are The Optic Nerves?
- Arise from the retinas
- Pass through the optic canals, converge and partially cross over at the optic chiasma
- Optic tracts continue to the thalamus, where they synapse
- Optic radiation fibers run to the occipital (visual) cortex
- Purely sensory (visual)
function
What are The Oculomotor Nerves?
- Fibers extend from the ventral midbrain through the superior orbital fissures to the extrinsic eye muscles
- Functions in raising the eyelid, directing the eyeball, constricting the iris (parasympathetic), and controlling lens shape
What Are The Trochlear Nerves?
- Fibers from the dorsal midbrain enter the orbits via the superior orbital fissures to innervate the superior oblique muscle
- Primarily a motor nerve that directs the eyeball
What are the The Trigeminal Nerves?
Largest cranial nerves; fibers extend from pons to face
* Three divisions
- Ophthalmic (V1) passes through the superior orbital fissure
- Maxillary (V2) passes through the foramen rotundum
- Mandibular (V3) passes through the foramen ovale
* Convey sensory impulses from various areas of the face (V1) and (V2), and supplies motor fibers (V3) for mastication
What are the The Abducens Nerves?
- Fibers from the inferior pons enter the orbits via the superior orbital fissures
- Primarily a motor, innervating the lateral rectus muscle
What are The Facial Nerves
- Fibers from the pons travel through the internal acoustic meatuses, and emerge through the stylomastoid foramina to the lateral aspect of the face
- Chief motor nerves of the face with 5 major branches
- Motor functions include facial expression, parasympathetic impulses to lacrimal and salivary glands
Sensory function (taste) from the anterior two-thirds of the tongue
What are The Vestibulocochlear Nerves?
- Afferent fibers from the hearing receptors (cochlear division) and equilibrium receptors (vestibular division)
pass from the inner ear through the internal acoustic meatuses, and enter the brain stem at the pons-medulla border - Mostly sensory function;
small motor component for adjustment of sensitivity of receptors
What are the The Glossopharyngeal Nerves?
- Fibers from the medulla leave the skull via the jugular foramen and run to the throat
- Motor functions: innervate part of the tongue and pharynx for swallowing, and provide parasympathetic fibers to the parotid salivary glands
- Sensory functions: fibers conduct taste and general sensory impulses from the pharynx and posterior tongue, and impulses from carotid chemoreceptors and baroreceptors
What are The Vagus Nerves?
- The only cranial nerves that extend beyond the head and neck region
- Fibers from the medulla exit the skull via the jugular foramen
- Most motor fibers are parasympathetic fibers that help regulate the activities of the heart, lungs, and abdominal viscera
- Sensory fibers carry impulses from thoracic and abdominal viscera, baroreceptors,
chemoreceptors, and taste buds of posterior tongue and pharynx
What are The Access nerve?
- Formed from ventral rootlets from the C1-C, region of the spinal cord (not the brain)
- Accessory nerves exit the skull via the jugular foramina to innervate the trapezius and sternocleidomastoid muscles
What are The Hypoglossal Nerves?
- Fibers from the medulla exit the skull via the hypoglossal canal
- Innervate extrinsic and intrinsic muscles of the tongue that contribute to swallowing and speech
Which cranial nerves have sensory functions only?
CNI (olfactory nerve), smell;
CNII (optic nerve), vision;
CNVIII (vestibulocochlear nerve), hearing and equilibrium
