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Chapter 8: Special Senses – THE EAR (pg. 292-299)

Notes Page: (This space is for you to take any notes you feel you need to)

External Ear


*Auricle (Pinna) –

*External Acoustic Meatus (Auditory Canal) –

*Tympanic Membrane (Eardrum) –

Middle Ear (Tympanic Cavity)


*Oval Window (Label on next page) –

*Round Window –

*Pharyngotympanic Tube (Auditory Tube) –

*Ossicles –

*Malleus (hammer) –

*Incus (anvil) –

*Stapes (stirrup) –

Internal (Inner) Ear


Alternative name for the inner ear –

*Cochlea –

*Vestibule –

*Semicircular Canals –


Membranous Labyrinth –

Endolymph –

Organs of Equilibrium

Equilibrium receptors of the inner ear are called the _____________________________.

Which has two parts:

  • _____________________ equilibrium

  • _____________________ equilibrium

Static Equilibrium (static = ____________________)

  • Maculae— ___________________________________________________________

    • Report on the ______________________ of the head

    • Send information via the vestibular nerve

  • Anatomy of the maculae

    • Hair cells are embedded in the otolithic membrane

    • Otoliths (tiny stones) float in a gel around the hair cells

    • Movements cause otoliths to bend the hair cells

Dynamic Equilibrium

  • These receptors respond to ___________________________________________ movements

  • Crista ampullaris— dynamic equilibrium receptors are located in the ____________________ of the_________________________________________________

  • Tuft of hair cells covered with _________________ (gelatinous cap)

  • If the head moves, the cupula drags against the endolymph

  • Action of angular head movements

  • The movement of the cupula stimulates the hair cells

  • An impulse from the hair cells is sent via the vestibular nerve to the cerebellum

Organs of Hearing

  • Organ of Corti

    • Located within the ____________________________

    • Receptors = ________________ _________________ on the basilar membrane

    • Gel-like tectorial membrane is capable of bending hair cells

    • Cochlear nerve attached to hair cells transmits nerve impulses to auditory cortex on temporal lobe

Mechanism of Hearing

  • In cochlea there’s three chambers. Top and bottom have perilymph and middle (cochlear duct) endolymph.

    • Organ of Corti in middle duct; this is where hearing receptors are located.
      • Vibrations from sound waves move tectorial membrane (of Corti) which makes,

      • hair cells bend which causes,

      • an action potential in the cochlear nerve which creates,

      • an impulse that travels to the temporal lobe where the interpretation of sound occurs

  • Receptor cells close to the oval window are stimulated

  • Low-pitched sounds disturb the long, floppy fibers of the basilar membrane

    • Specific hair cells further along the cochlea are affected

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