Cranial Nerves Flashcards
Cranial nerves I and II attach to:
Forebrain
Cranial nerves are attached to brain and pass through?
Foramina magnum of skull
CN I attached to:
Telencephalon
CN II attached to:
Diencephalon
Olfactory Nerves
Sensory nerves of smell
Olfactory System
afferent neurons on the nasal mucosal membrane, olfactory bulb, portions of temporal lobe and inferior frontal lobe, and limbic lobe
Unmyelinated axons of CN I terminate:
In the two olfactory bulbs
Cortical olfactory regions are responsible for:
Olfactory awareness
Limbic connects of Olfactory nerves responsible for:
integrating smell with emotional brain
Anosmia/hyposmia
Reduction/loss of ability to smell
Hyperosmia
Abnormally acute sensation of smell
CN II
Optic Nerve
Optic Tract terminates
Lateral geniculate body of thalamus
From LGB, optic radiations travel
primary visual cortex of occipital lobe
Optic nerve lesions result in
Ipsi Blindness
Chiasmatic lesion result in:
Bitemporal hemianopsia
Post chiasmatic lesions close to LGB result in:
Unilateral homonymous hemianopsia
Legions distal to geniculate ganglion result in:
upper or lower homonymous quadrantopsia
CN III
Oculomotor Nerve
Oculomotor Nerve innervates
Four of the six extrinsic eye muslces
Somatic portion of CNIII
responsible for eye and eye lid movement
Visceral portion of CNII
Controls function such as pupillary constriction
Unilateral damage to oculomotor nerve results in deficits in the:
ipsilateral eye
External opthalamoplegia
paralysis of extrinsic muscles leads to deviation of ipsi eye and eyelid drooping
Internal opthalomoplegia
paralysis of intrinsic muscles, permanent dilation of pupil
CN IV
Trochlear Nerve
CN IV Innervates
Innervates extrinsic eye muscle; moves eyeball outward and downward
CN IV is the only CN that:
exits posterior side of brainstem
Damage of CN IV
Difficulty of looking downward and outward
CN VI
Abducens nerve
CN VI innervares
Lateral rectus muscle, abducts eye ball
Medial longitudinal fasciculus important
coordinates eye muscles for gaze control
CN V
Trigeminal Nerve, largest
Sensory innvervations of CN V
From face & motor innervations to chewing muscle
Jaw Jerk reflex
Reflex arc of nerve
Three branches of trigeminal nerve
Opthalmic nerve, maxillary nerve, mandibular nerve
Responsible for cutaneous and proprioceptive sensations from face, head oral nasal
Trigeminal nerve
CN V controls muscles involved in chewing but not:
Facial expression
Mandibular nerve carries only:
general sensory sensation from the mouth, not taste
Taste from anterior 2/3 of tongue:
Cranial nerve VII
Taste from posterior 1/3 are carried by
Cranial nerve VII, IX, X
Trigeminal neuralgia
Intense pain in eyes lips, nose, scalp
Damage to motor portion of V
Paralysis of ipsilateral muscles of mastication
Wallenberg Syndrome
Loss/pain on face ipsi, but body contra
CN VII
Facial Nerve
Facial nerve is a
Mixed nerve,
Facial nerve controls
muscles of facial expression, but also taste information
Damage to CN VII at level of pons?
All three main functions will affect ipsi muscles, excessive secretion, and loss of taste
CN IX
Glossopharyngeal
Glossopharyngal function
sensory and motor innervations of structures of tongue and pharynx
Functions of IX include:
Sensory from post 1/3 of tongue, fibers to parotid salivary gland, motor fiberes to pharyngal muslces, swallowing
CN X
Vagus Nerve, mixed
Longest CN?
Vagus nerve
Vagus nerve important for?
Phonation and swallowing
Sensory information of Vagus
From external ear, pharynx, larynx, esophagus, trachea, heart
Motor fibers of vagus
Pharynx and most larynx, soft palate
CN XI
Accessory nerve, Controls head movement
CN XII
Hypoglossal nerve
Hypoglossal is a
motor nerve
Hypoglossal innervates
3/4 major extrinsic muscles of the tongue
Deviation of the ipsi eye to the lateral side
Lateral striabismus
Eyelid drooping
ptosis
Double vision
Diplopia
Permanent dilation of the pupil
mydriasis
Motor nucleus that controls lower half of face:
Receives projections from the contralateral motor cortex alone
Facial nucleus supplying upper facial muscles
received corticobulbar projects from both motor cortices
Controls all of our voluntary movement
Pyramidal motor system or tract
Two main neuron systems of Pyramidal system
UMN, LMN
Extra-pyramidal motor system
Responsible for maintaining rhythmic, phasic behavior, does not initiate movement
Upper motor neurons
Originate in the cerebral cortex, terminate in brainstem
Muscles of face, head and neck are controlled by:
Corticobulbar system
Lower motor neurons
Connect brainstem an dspinal cord to muscle fibers
Bell’s Palsy
Paralysis of upper and lower facial muscles
