The Cranial Nerves Flashcards
I
Olfactory
smell
nucleus: olfactory bulb
only nerve that DOES NOT TERMINATE IN THALAMUS to reach cortex
II
Optic
vision
nucleus: retinal ganglion cells
III
Oculomotor
eye movement, eyelid/pupil response
nucleus: oculomotor nucleus, Edinger-westphal nucleus
IV
Trochlear
eye movement down and laterally
nucleus: trochlear nucleus
V
Trigeminal
sensation in head and mastication
VI
Abducens
eye movement laterally out
nucleus: ipsilateral abducens nucleus
VII
Facial
facial expression, taste
nucleus: facial motor nucleus (pons)
VIII
Vestibulocochlear
balance and hearing
nucleus: cochlear nuclei
IX
Glossalpharyngeal
conveys info from intraoval receptors
X
Vagus
principle parasympathetic nerve
nuclei: dorsal motor nucleus, nucleus ambiguus, solitary nucleus, spinal trigeminal nucleus
XI
Accessory
neck and shoulder muscles
XII
Hypoglossal
tongue muscles
nucleus: hypoglossal nucleus
Somatic Sensory nerves
carries sensory info form muscles, skin, joins in periphery (V)
Visceral Sensory nerves
sensory info from viscera eg blood vessels and digestive (X)
Specialised sensory nerves
nose, eyes, ears (I, II, III)
Somatic motor nerves
fibers innervate skeletal muscle (III, IV, VI, XII)
Visceral motor nerves
preganglionic autonomic axons (X)
Brachiomeric nerves
motor axons that innervate striated muscles of special embryological origin (V, VII, X, VII, XI)
Optic nerve pathway
retina –> optic nerve –> optic chiasm –> optic tract –> lateral geniculate (thalamus) –> occipital cortex
Oculomotor nerve innervates -
medial rectus, inferior rectus, superior rectus, inferior oblique muscles, pupil, eyelids
damage to oculomotor nerve
strabismus (eyes unaligned)
diplopia (double vision)
ptosis (droopy eyelid)
Trochlear nerve
only nerve attached to dorsal surface of brainstem and only one to originate entirely contralateral nuclei
Trigeminal nerve - 3 branches
Opthalmic - top third of face (sensory)
Maxillary - middle third (sensory)
Mandibular - bottom third (sensory and motor)
Trigeminal nerve nuclei (4) and functions
Mesencephalic - proprioceptive info from muscles
Main sensory - tactile, travels in ascending pathway
Spinal Trigeminal - pain, temp, joins spinothalamic tract
Motor Trigeminal - innervates muscles of mastication
Trigeminal nerve ascending pathway
touch & proprioception from head –> synapse on main sensory nucleus –> cross midline, travels in medial lemniscus –> synapse in VPM of thalamus –> terminates in lateral part of postcentral gyrus
Abducens innervation and damage
innervates: lateral rectus of eye
damage: eye deviates medially (ipsi medial strabismus)
Facial nerve pathway
facial motor nucleus –> travels up and around abducens nucleus –> emerges from lateral pontine-medullary junction
Vestibulocochlear nerve pathway
hair cells in cochlea, fluid in semicircular canals –> nerve –> cochlear nuclei –> inferior colliculi –> medial geniculate thalamus –> auditory cortex
Glossalpharyngeal pathway
sensory: input from throat/posterior taste buds - solitary tract and nucleus
motor: output to throat for wallowing and salivary glands
nucleus ambiguus
Vagus nuclei and functions
Dorsal motor nucleus - parasympathetic output to viscer
Nucleus Ambiguus - vagal brachial innervates heart
Solitary Nucleus - vagal visceral sensory (gag reflex)
Spinal Trigeminal Nucleus - pain, touch, temp of outer ear, back of head, larynx
Accessory nerve pathway
enters brain thru foramen magnum –> travels inside skull –> sternocleidomastoid and trapezius muscles
