Lesson12 The inner ear

Cochlea

The part of the inner ear responsible for hearing.

Semicircular canals

Three tiny, fluid-filled tubes in the inner ear that help maintain balance.

Basal turn

The base of the cochlea located nearest to the oval window.

Apical turn

The other end of the cochlea coil, referred to as the apex.

Scala Vestíbuli

One of the three fluid-filled chambers in the cochlea.

Scala media

The middle fluid filled chamber of the cochlea that houses the organ of Corti.

Scala tympani

One of the three fluid-filled chambers in the cochlea.

Reissner’s membrane

Separates the Scala media from the Scala vestibuli.

Basilar membrane

Separates the Scala media from the Scala tympani.

Helicotrema

The point where the Scala vestibuli and Scala tympani meet at the apex of the cochlea.

Organ of Corti

The sensory receptor/end organ of hearing located in the Scala media.

Hair cells

Cells within the organ of Corti that are responsible for sensing sound.

Oval window

One of the two openings at the base of the cochlea for the transfer of energy between the middle and inner ears.

Normal human hearing range

Extends from 20 to 20,000 Hz.

Transfer of energy

Acoustical energy to mechanical energy to hydraulic energy to electrochemical energy

Place Theory of Hearing

Theory that states the structure of the basilar membrane determines where frequencies are recognized within the cochlea.

High frequencies response location

Basal turn of the cochlea.

Low frequencies response location

Apical turn of the cochlea.