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Departemen Anatomi
�Contain receptors for hearing & awareness of head position & movement
�Divided into :I. External ear � receives & directs
sound waves from external environment
II. Middle ear � tranforms sound waves into mechanical vibrations
III.Inner ear :o Mechanical vibration converted to nerve impulses & relayed to brain to be interpreted as sound
o Contain vestibular organs that function in balance
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� Auricle / pinna consist of :◦ Irregular plate of elastic cartilage, surrounded by thick pericondrium
◦ Skin with a few small hairs◦ Sebaceous gland & sweat gland◦ Sheets of skeletal muscle
� External auditory meatus :◦ An open S-shaped course◦ Lined by keratinized stratified squamous epith.
◦ Ceruminous gland :� Secretory cells : cuboidal to collumnar� Produced cerumen ( a waxy material that prevents drying of skin lines meatus)
� Auditory ossicles :◦ Malleus � M. tensor tymphani
◦ Incus◦ Stapes � M. stapedius
� Tympanic cavity � Lined by mucous membrane with a simple squamous epith.
� Tympanic membrane :◦ 3 layers :� Outer : stratified squamous epith
� Middle : 2 layers of collagenous fibers
� Inner : a simple squamous epith
◦ Inner surface attaches to malleus
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� Auditory tube / eustachian tube :◦ 4 cm long
◦ Connect anterior part of tympanic cavity with nasopharynx
◦ Wall of auditory tube :
� 1/3 near tympanic cavity supported by compact bone with simple columnar epith
� 2/3 medial supported by J-shaped elastic cartilage with ciliated pseudostratified columnar epith.
� Consist of :1. Periboney labyrinth / osseosa
labyrinth� filled with perilymph2. Membranous labyrinth � filled with
endolymph� Periboney & membranous labyrinth major components :a. Vestibular labyrinth � contain sensory
element for equlibrium b. Cochlea � contain sensory stuctures
for hearing� Perilymph :
◦ Resembles extracellular fluid (↑ sodium ions, ↓potassium ions)
◦ Production site : unknown� Endolymph :
◦ Resembles intracellular fluid ( ↑ potassium ion, ↓ sodium ions )
◦ Produced by striae vascularis (an area of cochlear duct)
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� Consist of 3 semisicular canals � utricle � saccule
� Most membranous labyrinth lined by simple squamous epith
� Sensory epithelium :◦ Stratified epith, found in spesific region of membranous labyrinth
◦ In semisircular canal �cristae ampularis
◦ Utricle � macula utriculi◦ Saccule �macula sacculi
◦ 3 type cells : hair cells type I & II, supporting (sustentacular) cells
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� Type I hair cells :◦ Flask-shaped with narrow apical region
◦ Rounded base contain nucleus
◦ Apical membrane bears 50-100 large, non motile microvilli, known as “hair”.
◦ Kinocilium : a single, eccentrically placed cilium, present on apical surface
� Type II hair cells �Similar to type I, but the cells are collumnar
� Supporting / sustentacular cells :◦ Columnar shaped◦ Function unknown◦ At periphery � planum semilunatum (simple columnar layer, lacks hair cells)
� Microvilli of hair cells in cristae embeded in gelatinous structure called cupula cristae ampullaris
� Microvilli of hair cells in maculae embeded in viscous proteoglycan, forms otholitic membrane. Numerous crystalline bodies / otolith suspended in this layer
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� Consist of : ◦ Outer portion of compact bone
◦ A central membranous part
� Osseous cochlea :◦ Mediolus
◦ Spiral lamina � basilar
membrane & vestibular membrane
◦ Spiral ligament
� Cochleal canal divided by basilar & vestibular membrane into :1. Upper scala vestibuli �
perilymph2. Scala media �
endolymph3. Lower scala tympani �
perilymph
� Striae vascularis :◦ Pseudostratified
columnar epith ◦ Contain basal &
marginal cells◦ Marginal cell may
elaborte in endolymph
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� Organ of corti :◦ Specialized cells on
scala media that transform vibrations of basilar membrane to nerve impulse
◦ Supporting cells �a tall columnar, consist of :1. Inner & outer
pillar cells2. Inner & outer
phalangeal cells
3. Border cells4. Cells of hensen
5. Cells of claudius
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1. Histologi Dasar, 8th
Edition, L. Carlos Junquira MD, Jose
Carneiro MD, Robert O. Kelley PhD, EGC, 1995.
2. Essentials of Human Histology, 2nd Edition, William J. Krausse PhD, Little Brown & Company
(Inc), 1996. Pp
3. Atlas Histologi Manusia, 6th Edition, Mariano S. H. di Fiore, EGC, 1992.