Nervous System - Cranial Nerves Flashcards
CN I
Olfactory N.
special sense of smell
Location: Olfactory bulb + tract inferior/medial to Frontal lobe. Hair-like nerves come from bulb to pass thru Cribiform plate of ethmoid bone. Lateral of Crista Gali
CN II
Optic N. (carries visual info fr one eye only)
attached to posterior aspect of eyeball. receives info fr one Retina and transports posteriorly to Occipital Lobe. Pass thru Optic Canal in Sphenoid bone
CN III
Oculomotor N. (oculo=eye; eye mvmt.)
originates in cerebral peduncles, moves anteriorly to pass thru Superior orbital fissure to reach the eye.
Muscles: Superior, Inferior, Medial, Inferior Oblique, Levator Palpebrae Superioris (eyelid)
Parasympathetic: constriction of pupil, + lens accommodation (maintain focus on object)
CN IV
Trochlear N.
1/6 extraocular muscle: Superior Oblique Muscle
Originates posteriorly of brainstem, travels a long way to pass thru Superior orbital fissure
CN V
Trigeminal N. (“3 twins” V1, V2, V3)
General Somatic Afferent fibers innervates structures of viscerocranium (like dura mater), skin covering face, mandibular+maxillary teeth, mucosal lining of oral + nasal cavity
“Standing Room Only” indicates first letter of foramen each divisioin enters: originates lateral side of Pons. V1 passes thry Superior Orbital Fissure, V2 passes Rotundum Foramen, V3 passe thru Ovale Foramen
CN VI
Abducens N.
1/6 extraocular muscle:
Lateral Rectus
originates lateral to dorsal mid Pons, in the floor of 4th ventricle via Suborbital Fissue
CN VII
Facial N.
(motor, sensory, + parasympathetic)
Originates in Posterior Cranial Fossa, pass thru Internal Acoustic Meatus, pass thru Stylomastoid Foramen, penetrate/pass thru Parotid Gand (salivary gland) where it branches out superiorly, inferiorly, and anteriorly to target organs
CN VIII
Vestibulocochlear N.
special sense of hearing + balance
double barreled appearance because of 2 nerves attached together
Vestubular N. attaches to Semicircular Canals (in ear)
Cochlear N. to Cochlea responsible for hearing
originates pontomedullary junction of brainstem, passes thru Internal Acoustic Meatus, terminates in temporal bone, in our ear
CN IX
Glossopharyngeal N.
motor/sensory/parasympathetic
lateral aspect of brainstem thru jugular foramen,
CN X
Vagus N.
motor/sensory/parasympathetic
largest CN
In posterior cranial fossa, pass thru Jugular Foramen, and descends along Corotid Artery
CN XI
Accessory N.
Sternocleidmastoid (SCM) + Trapezius muscles
2 points of origin (cervical spinal cord + brainstem) ascends up Foramen Magnum, then laterally to Jugular Foramen, and send branches to 2 muscles
CN XII
Hypoglossal N.
extrinsic (outside of tongue) + intrinsic (the tongue itself) muscles
travels down and thru hypoglossal canal near foramen magum, descend parallel to Carotid Artery to tongue.
mnemonic device for CN names
O, O, O, To Touch And Feel Very Good Velvet At Home
mnemonic device for CN
sensory, motor, or both?
Some Say Marry Money, But My Brother Says “Big Brains Matter More”
Parasympathetic/Autonomic CN
CN III, VII, IX, X
Optic Chiasm
crossing-like structure along visual pathway where signals from both eyes communicate w each other
Tochlea
tendon in eye for superior oblique
Superior Oblique
muscle on eye that helps mvmt inferio-laterally
Trigeminal V1 Division
Opthalmic Division (Sensory) cutaneous sensation to forehead, bridge of nose, and surface of eye
Trigeminal V2 Division
Maxillary Division
(Sensory)
cutaneous sensation to cheek, face, upper lip, nasal + oral cavities, and upper teeth
Trigeminal V3 Division
Mandibular Division (Motor/Sensory)
General Somatic Afferent: cutaneous ear, face, jaw, lower lip, inside oral cavity, tongue
Somatic Branchial Efferent fibers innervate head + neck muscles for mastication:
Masseter, Temporalis, Medial + Lateral Pterygoid, Mylohyoid Muscle, Tensory Tympani Muscle, Tensor Veli Palatani Muscle
CN VII - Sensory
innervates anterior 2/3 of tongue for TASTE
located in Geniculate Ganglion located in facial canal of temporal bone
CN VII - Motor
facial expression
Originates in Tegmentum of the Pons
CN VII - Parasympathetic
Sublingual + submandibular glands (for salivation), Lacrimal gland (tear)
Originates from Superior Salivary nucleus of the pons
Semicircular Canal
innervated by VIiI, the vestibular portion.
Located in middle ear as loops that contain liquid for equilibrium
CN IX Sensory
General + special sense of taste to posterior 1/3 of tongue,
sensations of pharynx,
monitors blood pressure + oxygen levels to brain on Carotid Sinus + Carotid Body (blood vessels)
CN IX Motor
Stylopharyngeus Muscles assist to elevating the harynx
CN IX Parasympathetic
innervates Parotid Glandsfor salivation
Jugular Foramen Mnemonics
if you cut a jugular, then call “911”
CN 9, CN 10, CN 11
CN X - Motor
soft palate muscles, pharyngeal + laryngeal muscles
to help swallow, modulate voice of larynx,
CN X - Sensory
General sense of inferior pharynx + larynx, thoracic + abdominal organs
CN X - Parasympathetic
Thoracic + abdominal viscera up to 2/3 of transverse colon
Foramens of CN
1 Cribriform Plate 2 Optic Canal 3 Superior Orbital Fissure 4 Superior Orbital Fissure 5 5.1 Superior Orbital Fissure 5.2 Foramen Rotundum 5.3 Foramen Ovale 6 Superior Orbital Fissure 7 Internal Acoustic Meatus 8 Internal Acoustic Meatus 9-11 Jugular Foramen 12 Hypoglossal Canal
