Brain stem & Cranial nerves Flashcards
What does the Pineal gland control?
Melatonin secretion & circadian rhythms
What does the Superior colliculi control?
Conjugate verticle gaze center
What does the Inferior colliculi control?
Auditory
What is Parinuad synd?
Paralysis of conjugate verticle gaze d/t lesion in superior colliculi
What is the function of Olfactory CN I?
Smell
Sensory
What is the only CN w/o thalamic relay to cortex?
CN I
What is the function of Optic CN II?
Sight
Sensory
What are the functions of Oculomotor CN III?
- Eye movement
- Pupillary constriction
- Accomodation
- Eyelid opening
- Motor CN
Which muscles does the Oculomotor CN III control?
- Superior rectus
- Infertior rectus
- Medial rectus
- Inferior oblique
- Levator palpebrae
- Sphincter pupillae
What is the function of the Trochlear CN IV?
Eye movement (superior oblique)
Motor
What are the functions of the Trigeminal CN V?
- Masicuation
- Fascial sensation
- Somatosensation from anterior 2/3 of tongue
- Both motor & sensory
What is the function of Abducens CN VI?
Eye movement (lateral rectus)
Motor
What are the functions of Facial CN VII?
- Facial movement
- Taste from anterior 2/3 of tongue
- Lacrimation
- Salivation (submandibular & sublingular glands)
- Eyelid closing (orbicularis oculi)
- Stapedius muscle in ear
- Both motor & sensory
What are the functions of Vestibulochlear CN VIII?
Hearing & balance
Sensory
What are the functions of Glossopharyngeal CN IX?
- Taste & somatosensation from posterior 1/3 of tongue
- Swallowing
- Salivation (parotid gland)
- Monitoring carotid body & sinus chemo- & baroreceptors
- Stylopharyngeus (elevates larynx, pharynx)
What are the functions of Accessory CN XI?
- Head turning
- Shoulder shrugging (SCM, trapezius)
- Motor
What is the function of Hypoglossal CN XII?
Tongue movement
Motor
Which CN nuclei are in the Midbrain?
CN III & IV
Which CN nuclei are in the Pons?
CN V, VI, VII, VIII
Which CN nuclei are in the Medulla?
CN IX, X, XII
Which CN nuclei are in the Spinal cord?
CN XI
Which CN exit the base of the brain & not the brain stem?
CN I & II
What are the Lateral nuclei?
Sensory
(Alar plate)
What are the medial nuceli?
Motor
(Basal plate)
Which CN’s are involved in the Corenal reflex?
- Afferent: V1 ophthalmic (nasociliary branch)
- Efferent: VII (temporal branch: orbicularis oculi)
Which CN’s are involved in the Lacrimation reflex?
- Afferent: V1 (loss of reflex does not preclude emotional tears)
- Efferent: VII
Which CN’s are involved in the Jaw jerk reflex?
- Afferent: V3 (sensory–muscle spind from masseter)
- Efferent: V3 (motor–masseter)
Which CN are involved in the Pupillary reflex?
- Afferent: II
- Efferent: III
Which CN are involved in the Gag reflex?
- Afferent: IX
- Efferent: X
What are the Vagal nuclei?
- Nucleus soliatrius
- Nucleus ambiguus
- Dorsal motor nucleus
What is the Nucleus solitarius?
Visceral sensory info
CN VII, IX, X
What is the Nucleus ambiguus?
Motor innervation of pharynx, larynx & upper esophagus
CN IX, X
What is the Dorsal motor nucleus?
Sends PNS fibers to heart, lungs & upper GI
CN X
What passes through the Cribriform plate?
CN I
What passes through the Middle cranial fossa?
CN II-VI through sphenoid bone
What passes through the Optic canal?
CN II, opthalamic artery & central retinal vein
What passes through the Superior orbital fissure?
- CN III, IV, V1, VI
- Ophthalmic vein
- Sympathetic fibers
What passes through the Foramen Rotundum?
CN V2
What passes through the Foramen Ovale?
CN V3
What passes through the Foramen Spinosum?
Middle meningeal artery
What passes through the Posterior cranial fossa?
CN VII-XII through temporal or occipital bone
What passes through the Internal auditory meatus?
CN VII, VIII
What passes through the Jugular foramen?
CN IX, X, XI, jugular vein
What passes through the Hypoglossal canal?
CN XII
What passes through the Foramen magnum?
Spinal roots of CN XI, brain stem, vertebral arteries
What is the Cavernous sinus?
A collection of venous sinuses on either side of the pituitary
Blood from eye & superficial cortex→ cavernous sinus→ internal juglar vein
What structures pass through the Cavernous sinus?
- CN III, IV, V1, V2, VI
- Postganglionic sympathetic fibers to orbit
- Cavernous portion of internal carotid artery
What is Cavernous sinus syndrome?
Opthalmoplegia & dec corneal/maxillary sensation w/ normal vision d/t mass effect, fistula or thrombosis
What is the CN V motor lesion?
Jaw deviates TOWARD side of lesion d/t unopposed force from opposite pterygoid muscle
What is CN X lesion?
Uvula deviates AWAY from side of lesion
Weak side collapses & uvual points away
What is CN XI lesion?
Weakness turning head to contralateral side of lesion (SCM)
Shoulder droop on side of lesion (trapezius)
What is CN XII lesion (LMN)?
Tongue deviates TOWARD side of lesion (“lick your wounds”) d/t weakened tongue muscles on the affected side
What are the findings in Conductive hearing loss?
- Rinne test: ABN (bone>air)
- Weber test: Localizes to affected ear
What are the findings in Sensorineural hearing loss?
- Rinne test: Normal (Air>bone)
- Weber test: Localizes to unaffected ear
What is damaged in Noise-induced hearing loss?
Stereocilliated cells in organ of Corti
What is lost first in Noise-induced hearing loss?
High-frequency hearing
What is the cause of Noise-induced hearing loss?
Sudden extremely loud noise can produce hearing loss d/t typmanic membrane rupture
What is a Facial UMN lesion?
Lesion of motor cortex or connection b/w cortex & facial nucleus
What are the clinical findings in Facial UMN lesions?
Contralateral paralysis of lower face
Forehead spaced d/t bilateral UMN innervation
What are the clinical findings in Facial LMN lesions?
Ipsilateral paralysis of upper & lower face
What is Facial nerve palsy?
Complete destruction of the facial nucleus itself or its branchial efferent fibers (facial nerve proper)
What are the clinical findings of Facial nerve palsy?
Peripheral ipsilateral facial paralysis w/ inability to close eye on invovled side
What is idiopathic Facial nerve palsy?
Bell’s palsy
gradual recovery in most cases
What disorders is Facial nerve palsy seen as a complication?
- AIDs
- Lyme dz
- HSV
- Herpes zoster (less common)
- Sacroidosis
- Tumors
- Diabetes
Which muscles close the jaw?
- Masseter
- Temporalis
- Medial pterygoid
Which muscle opens the jaw?
Lateral pterygoid
What are the muscles of the jaw innervated by?
Trigeminal nerve (V3)