Download Cranial Nerves Special Sensory Nerves I, II and VIII

Cranial Nerves
Special Sensory Nerves
I, II and VIII
embryonic placodes are associated with these nerves
head of embryo
olfactory
placode
otic placode
lens
placode
notes
the lens placode develops into the lens
the retina develops from the embryonic diencephalon
Cranial Nerve I Olfactory Nerve
cribriform plate of ethmoid bone
figure 13-10
cranial nerve I terminates in olfactory bulbs
axons of olfactory receptor neurons synapse on dendrites of mitral cells
in olfactory glomeruli
olfactory tract
mitral
cells in
olfactory
bulb
olfactory
glomeruli
cribriform
plate
olfactory receptor neurons
from figure 13-15 (5), 13-16 (6)
Cranial Nerve II
Optic Nerve
eye - development of retina and lens
prosencephalon
lens
vesicle
future neural
retina
future
cornea
lens
optic
vesicle
optic cup
four weeks
five weeks
six weeks
from figure 17-1 (5,6)
retina develops from diencephalon
developed retina
photoreceptors
horizontal cells
bipolar cells
amacrine cells
ganglion cells
figures 17-4 and 17-5 (5 and 6)
ganglion cells of retina
optic nerve
optic disk
figure 17-9 (5 and 6)
Cranial Nerve II
optic nerve
part of the CNS
million axons
meninges
multiple targets
optic nerve
optic chiasm
optic tract
retinal cells whose axons form CN II
are CNS neurons
the optic nerve is actually
a fiber pathway (“tract”) of the CNS
Cranial Nerve II
optic nerve
left
visual field
right
visual field
left
visual field
right eye
left eye
temporal side
of retina
right
visual field
nasal side
of retina
optic nerves
optic chiasm
optic tract
lateral geniculate
nuclei
figures 17-24 (5),17-27 (6)
visual field deficits
left eye
vision
right eye
vision
damage of
left optic nerve
left eye
vision
right eye
vision
ipsilateral blindness
damage to
middle of chiasm
left eye
vision
right eye
vision
bitemporal hemianopia
damage to
left side of chiasm
left eye
vision
right eye
vision
ipsilateral nasal
hemianopia
damage to
left optic tract
left eye
vision
right eye
vision
contralateral homonymous
hemianopia
Cranial Nerve VIII
two components
auditory
vestibular
kinocilium degenerates
auditory structures in inner ear
auditory sensory cells: hair cells
sensory receptor cells
stereocilia
(microvilli)
neurotransmitter
vescicles
distributed along membrane within cochlea
figure 14-3 (5) and (6)
auditory afferents of CN VIII
innervate base of hair cells
“
auditory afferents in CN VIII
to
brain stem
emerge from petrous bone
approach rostral medulla / caudal pons
cell bodies of sensory afferents
at core of cochlea
rostral medulla/caudal pons
X
spiral ganglion in cochlea
cochlear
nuclei
auditory
CN VIII
cochlear nuclei
vestibular nuclei
auditory efferents in VIIIth Nerve
hair cells in cochlea
Cranial Nerve VIII
auditory
two components vestibular
kinocilium
stereocilia
(microvilli)
sensory structures in inner ear
vestibular sensory cells: hair cells
neurotransmitter
vescicles
distributed along membrane within vestibular organs
two kinds of vestibular sensory organs in inner ear
SSD (A)
SSD(H)
semicircular ducts
or canals (SSD)
(3 sets)
anterior
posterior
horizontal
U
S
otolithic organs
(2 sets)
SSD (P)
utricle (U)
saccule (S)
vestibular afferents of CN VIII
innervate base of hair cells
cell bodies of sensory afferents
in vestibular ganglion
to
brain stem
vestibular afferents in CN VIII
emerge from petrous bone
approach rostral medulla/caudal pons
rostral medulla/caudal pons
superior
vestibular
nuclei
lateral
medial
inferior
vestibular structures
of inner ear
vestibular
ganglion
vestibular
CN VIII