Cranial Nerves 5 9 10 will be on exam Nerve 1 Purely for sense of smell olfactory nerve NO motor functions When the olfactory nerve fibers go up through the cribiform plate through the ethmoid bone the nerves synapse with the olfactory bulb and then relay that information to the olfactory areas of the cerebral cortex Nerve 2 Purely sensory cranial nerve specially for vision NO motor function Nerve 3 Oculomotor nerve PURELY motor nerve NO sensory function Comes from the midbrain then enters ocular cavity Third nerve is thicker than fourth nerve Supplies 4 of the 6 muscles that move the eye Motor to muscle called the levator palepbrae also elevates upper eyelid Also has an autonomic component Parasympathetic axons traveling with this nerve are involved in a visual reflex pathway to constrict or decrease the size of the pupil Pupillary light reflex innate reflex Parasympathetics also go to a part of the eye to help with accommodation or changing depth perception innate reflex BLUE BOX ON 14 21 for VISUAL SYSTEM Nerve 4 PURELY motor nerve NO sensory function Comes from the midbrain Nerve 6 PURELY motor nerve eyeball Like trochlear nerve only supplies one small muscle that moves the eye Lateral rectus Parasympathetics also go to a part of the eye to help with accommodation or chan Will not be expected to know the muscles of the eye Nerve 5 Trigeminal Nerve Mostly sensory has a motor component as well Leaves the pons Cell bodies in the sensory ganglion are unipolar neurons identical in morphology to the unipolar neurons of dorsal root ganglion This nerve has 3 major branches 1 Opthalmic Branch Goes into the orbit Sensory nerve of the eyeball Not for vision but for carrying sensation pain pressure touch from the eyeball into the brain The cornea of the eye is loaded with opthalmic nerve sensory endings Exam Q Sensory innervation of the cornea is provided by Trigeminal nerve or opthalmic branch of trigeminal nerve Also carries sensory information from epithelial lining of nasal cavity and sensory information from sensations in forehead 2 Maxillary Branch Closely related to maxillary bone of skull Sensory information from hard palate roots of upper teeth upper lip skin of nose skin of cheeks etc 3 Mandibular Branch Travels in boney canal in the mandible Provides sensory roots to all of the lower teeth and tongue Also carries motor fibers to the muscles of mastication chewing Motor fibers here piggy back on the sensory fibers to get to the muscles of mastication that they need to supply masseter temporalis and turgoid Exam Q Which muscle receives stimulation from the trigeminal nerve or mandibular branch of trigeminal nerve A Masseter or temporalis Facial Nerve 7 Leaves the pons and enters the face through the base of the skull to provide motor muscles in all the muscles of facial expression and also helps salivary glands Also carries the sense of taste from the anterior two thirds of the tongue Nerve 8 Vestibulochoclear Nerve Leaves brain stem enters temporal bone Vestibular branch carries sensory information relevant to balance and equilibrium hearing Cochlear branch goes to the cochlea which contains sensory receptors for Damage could result in loss of hearing in one ear as well as problems with balance Nerve 9 Glossopharyngeal Nerve Parasympathetics provide parotid salivary gland Gagging and vomiting Nerve 10 Vagus Nerve Comes out of medulla Territory of supply is very large Mixed nerve has a few sensory fibers and some motor Majority of nerve is autonomic parasympathetic innervation of The heart for reflex slowing of heart rate Both lungs and part of the airway Digestive tract Vagus nerve is motor to the skeletal muscle of the pharynx Laryngeal nerve Important for swallowing Motor limb of gagging and swallowing reflexes innate Motor branches supply all of the skeletal muscle of the larynx Pharyngeal nerve Nerve 12 Hypoglossal Nerve PURELY motor nerve Motors to the tongue Nerve 11 Accessory Nerve PURELY motor nerve Purely motor nerve to trapezius and sternocleidomastoid muscles Nerves 5 7 9 10 are both sensory and motor Cranial Meninges Meninges of the Brain Outer Periostial layer of the dura contains bone forming cells Inner Meningial layer of the dura is called the meningial layer of the dura Forms partitions in the skull called dural septa Falx cerebra Division between the brain Positions hemispheres As the layers of the dura separate throughout the skull they form sinuses Arachnoid vili are important for return of CSF to vascular system Epidural hematoma Artery is ruptured and blood pours out and peels the dura matter away from the skull and puts pressure on the brain Subdural hematoma Deoxygenated blood Dural septa 1 Falx cerebri 2 Falx cerebelli 3 Tentorium cerebelli 4 Diaphragma sellae Cerebrospinal Fluid should not contain red blood cells 2 Lateral ventricles one in each cerebral hemisphere 3rd ventricle contained in diancephalon Cerebral aqueduct courses through the midbrain Know ventricles and everything about them apparently