AP Psych Hearing and the Ear

Eardrum

A tight membrane that vibrates when in contact with sound waves; helps to amplify the sound waves as they lose strength travelling down the auditory canal

Semicircular Canals/Vestibular Sacs

Attached to the canals of the cochlea; they contain fluids, which, when the head is rotated and fluids jostled, helps to determine the head's position and movement (vestibular sense)

Outer Ear

Channels sound waves through the auditory canal towards the eardrum

Inner Ear

Consists of the cochlea, the semicircular canals, oval window, basilar membrane, auditory nerve, and hair cells

Middle Ear

Consists of three small bones--the hammer, anvil, and stirrup, called the ossicles.

Auditory Nerve

Convergence of axons of the nerve cells adjacent to the hair cells, which then sends neural messages to the auditory cortex (in the temporal lobe)

Basilar Membrane

Membrane within the cochlea; the vibration caused by the jostled fluid in the cochlea bends the hair cells lining its surface

Oval Window

Outer membrane of the cochlea, attached to the stirrup, which vibrates when the ossicles vibrate, and jostles the fluid within the cochlea

Ossicles

Series of three tiny bones in the middle ear (the hammer, the anvil, and the stirrup) that vibrate when in contact with the vibrations of the eardrum

Amplitude

Strength of wave; determines a sound's loudness

Cochlea

Tightly-wound structure within the inner ear, whose fluids, when vibrated by the ossicles, are jostled, which causes ripples in the basilar membrane.

Frequency

Wavelength; determines pitch

Hair Cells

When the hair cells are bent by the jostled fluid in the cochlea and the ripples in the basilar membrance, the hair cell movement triggers a neural impulse in adjacent nerve cells