12/3/2010 1 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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12/3/2010
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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.
� 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