7.2 Cranial nerves Flashcards
What are the modalities of cranial nerves?
General sensory: Perception of pain, temperature, & touch
Special sensory: Vision, smell, hearing, balance, & taste
Visceral sensory: Sensory input from viscera
Skeletal motor: Motor innervation to skeletal muscle
Visceral motor: Motor innervation to smooth muscle, organs, & glands
Describe CN I
olfactory nerve
- Sensory: olefaction
- from olfactory receptor cells of nasal cavity
- Pass through cribriform plate (of ethmoid bone)
- Fibers synapse in olfactory bulbs
- Pathway terminates in primary olfactory cortex
Describe CN II
- Sensory: vision
- Arise from retinas; Pass through optic canals, converge & partially cross at optic chiasma (right visual field in left cortex)
- Optic tracts continue to thalamus (LGN);
Optic radiation run to visual cortex
decribe CN III
- MOTOR
- Stomatic: riasing eyelid (levator palpebrae superioris), directing eyeball (4 extrinsic eye muslces)
- PSNS: sphincter pupillae & cilliary muscle (adjsuts pupil size)
- exits through sueprior orbital fissue -> various muslces around/in eye
Describe CN IV
- trochlear nerves
- superior oblique msucle (bends around a trochlea)
- exists throuhg superior orbital fissure
Describe CN VI
- the abducens nerve
- Motor: lateral rectur muscle (when they contract, eyes abduct)
- exit through superior orbital fissure (a lot goes through that)
what nerves contorl different eye muscles
LR6SO4 and rest are 3
Lateral rectus: CN VI (abductens)
Superior oblique: CN IV (trochlear)
medial rectus, superior rectus, inferior rectus, and inferior oblique all by CN III
descrine CN V
trigeminal nerves
- has 3 divisions: opthalamic (V1), maxillary (V2) and mandibular (V3)
describe the divisions of the trigeminal nerves
-
Ophthalamic (V1): passes throuhg superior orbital fissue, only sensory function
- forhead area, can pick up feeling of cavity in upper tooth,
- Maxillary (V2): passes through foramen rotundum, only sensory
-
mandicular (V3): passes through foramen ovale, sensory and motor
- muscles of mastication and tensor tympani and tensor veli palatine (ear muscle that dampens sound)
Describe CN VII
facial nerves
- travels through internal acoustic meatus to exit skull via stylomastoid foramina
-
motor:
- muscles of facial expression (opens eyes + mouth very wide, ie lion/lemon face)
- PSNS to glands (lacrimal (tear), nasal (snot), palatine, submandibular and sublingual (saliva)
-
sensory function
- taste from anterior 2/3 of tongue
- skin external acoustic meatus & auricle
placement of facial nerves
*CN VII
describe CN VIII:
vestibulocochlear nerves (auditory nerve)
- Sensory: hearing (cochlear division) & equilibrium balance (vestibular division)
- afferent fibers pass from inner ear to brainstem through internal acoustic meatuses
Describe CN IX:
Glossopharyngeal nerves
- exit through jugular foramen (goes thru tongue and pharynx)
-
Motor
- PSNS fibers to parotid gland
- stylopharyngeus (elevates pharynx during swallowing)
-
Sensory
- taste: posterior 1/3 tongue
- sensory: posterior 1/3 tongue, oropharynx, tympanic membrane, middle ear, auditor tube
- impulses from carotid chemoreceptors and barorecaptors
- helps pick up how blood flow is going to brain
*to check it test gag reflex
describe CN X
vagus never
- exit skull via jugular foramen
-
motor
- PSNS innervation of heart, lungs & abdominal viscera
- muscles of larynx and pharynx (imp for speech, issues with vagus nerve -> 1st symptom if hoarsness in voice)
-
Sensory
- sensory form thoracic/abdominal viscera & posterior ear/external acoustic meatus
- barorecaptors and chemoreceptors (detect changes in blood)
- taste from posterior tongue and pharynx
Describe CN XI
spinal accessory nerves
-
Motor: trapezius and sternocleidomastoid
- formed from ventral rootlets from C1-C5 region of spinla chord (not of brain)
- exists skull @ superior aspect of spinal chord
- rootlets pass into cranium via foramen magnum
- accessory nerves exit skill via jugular foramina
- formed from ventral rootlets from C1-C5 region of spinla chord (not of brain)
*to test turn head against pressure
Describe CN XII
hypoglossal nerves
motor: innervate majority of tongue muscles contributing to swallowing, speech and mastication
exit skull via hypoglossal canal (hole right near tongue)
*test: stick out tounge
Role of cranial nerves
CNI: Olfactory : SENSORY
CN II: Optic: SENSORY
CN III: Oculomotor : MOTOR
CN IV: Trochlear: MOTOR
CN V: Trigeminal: BOTH
CN VI: Abducens: MOTOR
CN VII: Facial: BOTH
CN VIII: Vestibulocochlear/Auditory: SENSORY
CN IX: Glossopharyngeal: BOTH
CN X: Vagus BOTH
CN XI : Spinal accessory; MOTOR
CN XII: Hypoglossal : MOTOR
oh, oh, oh to touch and feel a girls very soft hand
some say money matters, but my brother says big brains matter more
cranian nerve innvervation of tongue: motor function
CNX: muscles of pharynx
CN XII: all of muslces of tongue and pharynx
cranial nerve innervation of tongue: sensory
CN IX: general sensory (ability to feel tongue, ie biting it)
CN X: taste
CN iX: general sensory and taste
CN V3: general sensory
CN VII: taste
What nerves are involved in general sensory modality (pain temp, touch)
CN: V, VII, IX, X
what cranial nerves are associated with special sensory (vision, smell, hearing, balance, and taste)
CN: I, II, VII, VIII, IX, X
what cranial nerves are involved in visceral sensory (input from viscera)
IX, X
What cranial nerves are invovled in skeletal motor modalities (motor innervation to skeletal muscle)
CN; III, IV, V, VI, VII, IX, X, XI, XII
What cranial nerves are involes in visceral motor function (motor innervation to smooke muscle, organs and glands)
CN III, VII, IX, X
