1. Figure 25.1 Anatomy of the ear.
External
ear
Middle
ear
Internal ear
(labyrinth)
Auricle
(pinna)
Malleus
(hammer)
Incus
(anvil)
Auditory
ossicles
Helix
Stapes
(stirrup)
Lobule
External
acoustic
meatus
Tympanic
membrane
Pharyngotympanic
(auditory) tube

2. Superior vestibular ganglion
Figure Internal ear.
Temporal
bone
Semicircular ducts in
semicircular canals
Facial nerve
Vestibular nerve
Anterior
Superior vestibular ganglion
Posterior
Lateral
Inferior vestibular ganglion
Cochlear nerve
Cristae ampullares
in the membranous
ampullae
Maculae
Spinal organ
Utricle in vestibule
Cochlear duct in cochlea
Saccule in vestibule
Stapes in
oval window
Round window 2

3. Figure 25.3 Anatomy of the cochlea.
Inner
hair cell
Vestibular membrane
Osseous spinal lamina
Tectorial membrane
Tectorial membrane
Afferent
nerve
fiber
Spiral
ganglion
Hairs (stereocilia)
Cochlear duct
(scala media;
contains
endolymph)
Scala
vestibuli
(contains
perilymph)
Outer hair cells
Supporting cells
Stria
vascularis
Fibers of
cochlear
nerve
Spiral organ
Scala tympani
(contains perilymph)
Basilar
membrane 3

4. Figure 25.5 Resonance of the basilar membrane.
Stapes
Fibers of
cochlear
nerve
Scala
vestibuli
Oval
window
Perilymph
Round
window
Scala
tympani
Basilar
membrane
Cochlear
duct
Basilar
membrane
Base
Apex
Relative
lengths
of basilar
fibers
within
different
regions
membrane
500 Hz
4000 Hz
20,000 Hz Hz
20,000
(High notes) Hz
2000 Hz
200 Hz 20
(Low notes) 4

5. Figure 25.7 Structure and function of the crista ampullaris.
Ampullary cupula
Endolymph
Hair bundle
(kinocilium
plus stereocilia)
Hair cell
Crista
ampullaris
Membranous
labyrinth
Supporting
cell
Fibers of vestibular nerve
Flow of
endolymph
Direction of body movement 5

6. Figure 25.8 Scanning electron micrograph of a crista ampullaris (14×).
Ampullary cupula 6