Cranial nerves Flashcards
Name all of the Cranial Nerves
1) Olfactory Nerve 2) Optic Nerve 3) Oculomotor Nerve 4) Trochelar nerve 5) Trigeminal nerve 6) Abducent nerve 7) Facial nerve 8) Vestibulocochlear nerve 9) Glossopharyngeal nerve 10) Vagus nerve 11) Accessory nerve 12) Hypoglossal nerve
Which nerves are sensory, which are motor and which are both?
Where does the olfactory nerve exit from the skull/
Cribiform of the ethmoid bone
Describe the Olfactory Nerve
CNISensoryAllocortex/limbusFound in the Olfactory space. It projectsup from the cribriform plate of the ehtmoid muscle to form the olfatory bulb, and this olfactory bulb forms the olfactory tract which projects to the Primary olfactory cortex in the brain. (note that the olfactory tract is part of the limbic system- why smells trigger memories/emotions).Involved in smell
Describe the Optic Nerve
CIISensoryAllocortex/LimbusExits: Optic CanalConnect to the back of the retina, pass through the optic canal to the optic chiasma. These fibres then get mixed then form the optic tract then synapse with the Lateral geniculate nucleus of the thalamus which sends info to the cortex.Vision
Describe the Occulomotor Nerve
CNIIIMotorMidbrainExit: Superior Orbital fissureControls majority of the muscles that control the movement in the eye (1)Levator Palpebrae Superioris (elevates the superior (upper) eyelid), 2) Superior rectus, 3) Inferior rectus, 4) medial rectus, 5) inferior olique muscles)Also Innervates a number of theextraocular musclesas well as parasympathetic innervation on the 6)sphincter pupillae and the 7)ciliary muscles (responsible for accommodation fo the lesne for near vision)Elevates, abducts, adducts and depresses the eye.If this is damaged, the patient’s ability to depress the eye is often damaged (their eyes will move upwards)
Describe the Trochlear nerve
CN IVMotorMidbrainExit: Superior Orbital fissureMotornerve(a somatic efferentnerve) that innervates only a single muscle: the superior oblique muscle of the eye, which operates through the pulley-liketrochlea. (abducts, depresses and tortes/internally rotates the eye)
Describe the Trigeminal Nerve
CNVBoth sensory and motorPonsExit: Superior Orbital fissureThe three major branches of thetrigeminal nerve—the ophthalmicnerve(V1), the maxillarynerve(V2) and the mandibularnerve(V3)—converge on thetrigeminalganglion. These exit the cranium at different points because they divide before they exitIt supplies sensations to the face, mucous membranes, and other structures of the head.-Opthalmic nerve is involved in sensory innnervation of forehead, eyelid and top of nose. It is also involved in cornear, lacrimal glands-Maxillary get sensation from the lower part of the ye and upper lip. It also synapses with a ganglion that receives info from a lot of nerves from nose and mouth.-Mandibular gland also receives info from anterior 2/3 of tongue (pain and temp etc.), and also involved in getting info from the sweat glands and other structues in the mouth. It also synapses with the Otic ganglion which is involved in the regulation of the carotid glands (salivary glands).It is the motor nerve for the muscles of mastication (chewing) and contains proprioceptive fibers.
Describe the Abducent Nerve
CNVIMotorPonsExit: Superior Orbital FissureInnervates lateral rectus muscle (Thelateral rectus muscleis amuscleon thelateralside of the eyeball in the orbit. It is one of six extraocularmusclesthat control the movements of the eye. Thelateral rectus muscleis responsible forlateralmovement of the eyeball, specifically abduction)
Describe the Facial Nerve
CN VIIBoth sensory and motorPons/MedullaExit: Stylomastoid foramenControls the muscles offacial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue and oral cavity.(learn below)Motor:Innervates the muscles of facial expression, the posterior belly of the digastric, the stylohyoid and the stapedius muscles (control fo the eyelid, closing of the eyes, pouting of the mouth, movement of the cheek etc.)Sensory: A small area around the concha of the auricle.Special Sensory: Provides special taste sensation to the anterior 2/3 of the tongue. (Cauda tympani nerve)Parasympathetic: Supplies many of the glands of the head and neck, including:Submandibular and sublingual salivary glands,Nasal, palatine and pharyngeal mucous glands and the Lacrimal glands.
Describe the Vestibulocochlear Nerve
CN VIIISensoryMedullaExit: Leave cranial cavity through the internal acoustic meatusDamage to this nerve can result in vertigo (sensation of movement when you’re not), nausea, vommiting etc.Vestibular division = balanceCochlear division = hearing
Describe the glossopharyngeal nerve
CN IXBoth sensory and motorMedullaExit: Jugula foramenIt exits the brainstem out from the sides of the uppermedulla, just rostral (closer to the nose) to thevagus nerve.Control and receive info from the tongue (parotid gland)and parts of the throat. Mainly sensory but some control functions.Sensory: Innervates the oropharynx, carotid body (info about pressure), and carotidsinus (structure in the carotid that senses changes in pH, CO2, O2 etc.), posterior 1/3 of the tongue, middle ear cavity and Eustachian tube.Special Sensory:Provides taste sensation to the posterior 1/3 of the tongue.Parasympathetic: Provides parasympathetic innervation to the parotid gland (production of saliva).Motor: Innervates the stylopharyngeus muscle of the pharynx.
Describe the Vagus Nerve
CNXBoth sensory and motorMedullaExit: Jugular ForamenInterfaces with parasympathetic control of the heart, lungs, and digestive tract.Lots of nuclei and lots of branches that control exterior parts of the inner ear and oracle. Also receive sensory info from the meninges.1) Pharyngeal branch (motor control of muscles in the pharynx)2) Superior laryngeal branch (2 parts = internal which is involved in sensory from the larynx and external branch that is involved in motor)3a) Right nerve travels back up from under the subclavian artery to control the muscles3b) The left nerve passes under the aorta, then comes back up again (recurrent laryngeal nerve)Works with the sympathetic nervous system to regulate bodily function.
Describe the Acessory Nerve
CN XIMotorMedullaExit: Jugular foramenInnervates the sternocleidomastoid and trapezius muscles (rotation of the head and shrugging of the shoulders). Start in the Spinal cord and goes up into the cranium. The cranial portion joins with the vagus nerve very quickly.
Describe the Hypoglossal Nerve
CN XIIMotorMedullaExit: Hypoglossal canalInnervates the hypoglossus, genioglossus and styloglossus muscles and all intrinsic muscles of the tongue.(innervates all the extrinsic and intrinsic muscles of the tongue, except for the palatoglossus which is innervated by the vagusnerve. It is anervewith a solely motor function.)
