Re: Functional Components of the Cranial Nerves - T/F and Tutorial

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: : 1. The olfactory fasicles pass through the cribriform plate of the ethmoid bone to enter the nasal cavity. : True. : : 2. A fracture of the cribriform plate may cause a CSF leak. : True. Dura Mater (falx cerebri) is connected to the Crista Galli of the Ethmoid Bone. : (wikipedia search "cribriform plate") : : 3. The olfactory nerve has native SVA and GVE components. : False: No efferent components to speak of. : : 4. A hypophyseal tumor is expected to disrupt central vision. : True. Google search "Pituitary tumor" and look at associated symptoms that may arise. : : 5. The chiasmatic groove is posterior to the hypophyseal fossa. : False: the groove is anterior to the hypophyseal fossa. Google "sphenoid bone" to find a good image. : : 6. The afferent limb of the pupillary light reflex is mediated by the SSA component of the oculomotor nerve. : False: The optic nerve is responsible for the afferent limb of the pupillary reflex - it senses the incoming light. The oculomotor nerve is responsible for the efferent limb of the pupillary reflex - it drives the muscles that constrict the pupil. : (wikipedia "pupillary light reflex") : : 7. A lesion of the proximal superior division of the oculomotor nerve is expected to disrupt GSE and GVE components. : True. We should lose innervation of the superior/Inferior/Medial rectus muscle (for eyeball movement—the trochlear nerve does that lateral rectus), levator palpebrae (for eyelid opening), sphincter pupillae (for iris control allowing pupillary dilation), and ciliaris muscle (controlling the lens of the eye to allow for visual accommodation). : The GSE components are the skeletal muscles, whereas the GVE components are for the lens and pupil. : (Read more with a wikipedia search on "superior branch of oculomotor nerve") : : 8. Preganglionic GVE cell bodies from the Edinger-Westphal nucleus synapse in the submandibular ganglion. : False, these synapse in the ciliary ganglion. Baby Gray's p. 850. : : 9. The short ciliary nerves host native GSA fibers non-native preganglionic GVE fibers. : False. But I will say that I don't entirely understand the question (perhaps due to grammar?). I am under the impression that the ciliary nerves are derived from the oculomotor nerve which only carries two types of neurons: GSE and GVE (baby gray's pg. 850). : The GVE output controls 1) ciliary muscles, thereby altering the lens of the eye to accommodate images, and 2) sphincter pupillae muscles to dilate/constrict the pupil to adjust light intensity upon the retina. : : 10. Postganglionic GVE fibers having cell bodies in the ciliary ganglion mediate accomodation as well as pupillary dilation. : True. Details are elucidated in previous responses. : : 11. A lesion of the greater superficial petrosal nerve at the lacerate foramen disrupts preganglionic GVE fibers that influence lacrimation. : True. (Wikipedia search for "foramen lacerum") : : 12. The short ciliary nerves host non-native postganglionic fibers from both divisions of the autonomic nervous system. : True...except I dont know what "non-native" really means. The short ciliary nerves arise from the ciliary ganglion and are GVE fibers. It's a ganglion because thats the site of synapsing of the efferent neurons, which means the cell body's are those of the post-ganglionic neurons. : : 13. A lesion of the internal carotid nerve is expected to disrupt preganglionic sympathetic GVE fibers and cause unilteral mydriasis. : True. The internal carotid nerve courses with the internal carotid artery before it forms into the plexus. If it is damaged, it could create swelling, which in turn will impede upon the oculomotor's GVE functional components to the sphincter pupillae muscles causing a unilateral mydriasis. : (wikipedia search "blown pupil") : : 14. A cavernous sinus infection is expected to cause unilateral pupil dilation given that the sympathetic root of the ciliary ganglion remains healthy. : False. The sympathetic root would dilate the pupil to allow more light onto the retina. : : 15. A mild ptosis in a young person may be caused by a GVE disturbance whereas a frank ptosis is caused by GSE disturbance. : this is simply a drooping of the eyelid which is innervated by CN-III (to the levator palpebrae). This muscular innervation is under GSE control, not GVE control. I don't know the difference between frank and mild ptosis, so I don't know how to answer this question. : (wikipedia search "ptosis of the eyelid") : : 16. Sneezing while looking at bright light is thought to be, in part, mediated by the GSA component of the trigeminal nerve. : True. The probable cause is a congenital malfunction in nerve signals in the trigeminal nerve nuclei. The fifth cranial nerve, called the trigeminal nerve, is apparently responsible for sneezes. Research suggests that some people have an association between this nerve and the nerve that transmits visual impulses to the brain. Overstimulation of the optic nerve triggers the trigeminal nerve, and this causes the photic sneeze reflex. : (more or less copied directly from wikipedia search on "photic sneeze reflex") : : 17. The infraorbital nerve, while in the infraorbital canal, carries non-native postganglionic GVE fibers enroute to the lacrimal gland. : while in the infraorbital canal, the nerve is referred to as the maxillary nerve—which itself is the middle branch of the trigeminal nerve (CN-V). The opthalmic branch of the trigeminal is normally responsible for innervating the GVE component of the lacrimal gland. As far as it carrying non-native guys...I don't know...maybe? : : 18. The lacrimal nerve proper is GSA only and does not mediate lacrimation. : Could not find the function of the lacrimal nerve...help? : : 19. Traveling along with the distal parts of the lacrimal nerve are postganglonic GVE fibers whose cell bodies are located in the pterygopalatine ganglion. : True (?). Searched "pterygopalatine ganglion" and found that the lacrimal nerve arises from this ganglion. The lacrimal gland is not one of our special senses, so it goes under GVE control. : : 20. The extraocular muscles, with the exception of the superior oblique, are innervated by SVE fibers. : False. We can consciously control our eye movements, hence they are not Visceral, but rather, are Somatic. (i think) : : ps: sorry if that was too messy to follow! looking forward to hearing corrections...

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