Chapter 7: Audition (Hearing)

Sound

Produced by objects that vibrate and set molecules of air into motion

700

Sound travels ___ mph, with a range of 30-20k Hz

Waves

Stimulate receptor cells in ears, perceived as sounds

Pitch, loudness, timbre

3 perceptual dimensions of sound

Frequency

Pitch

Amplitude

Loudness

Complexity

Timbre

Outer Ear

Pinna, ear canal, tympanic membrane

Middle Ear

Ossicles

Hammer, anvil, stirrup

Order of the ossicles

Inner Ear

Eustachian tube, cochlea, oval, round window

Cochlea

Snail-shaped structure of inner ear that contains auditory transducing mechanisms

Oval Window

Opening in bone surrounding cochlea with membrane that transmits sound vibrations from ossicles into fluid of the cochlea

Round Window

Membrane-convered opening in bone surrounding cochlea that releases sound vibrations from the cochlea

Organ of Corti

Tectorial Membrane

T for top

Basilar Membrane

B for base/bottom

Inner Hair Cells

Responsible for normal hearing

Outer Hair Cells "Effector Cells"

Influence mechanical characteristics of basilar membrane

Tip Link

"tugs" on cation channels of hair cells; floods K+ and Ca2+

Hyperpolarized

0% probability of opening the cilia; from bending to smallest cilia

At rest

Slightly depolarized 10% probability of opening the cilia

Highly Depolarized

100% probability of opening the cilia; from bending to tallest cilia

First

___ (first/second/third/fourth/fifth/sixth), air molecules vibrate

Second

___ (first/second/third/fourth/fifth/sixth), tympanic membrane oscillates these vibrations

Third

___ (first/second/third/fourth/fifth/sixth), ossicles push on the oval window

Fourth

___ (first/second/third/fourth/fifth/sixth), liquid inside the cochlea moves from the upper to lower region

Fifth

___ (first/second/third/fourth/fifth/sixth), basilar membrane flexes to sound, depends on frequency

Higher, closest

___ frequencies flex the basilar membrane ___ to the oval/round window

Sixth

___ (first/second/third/fourth/fifth/sixth), hair cells located in the region where basilar membrane flexes are pushed toward the more rigid tectorial membrane

Cochlear Nucleus

Nuclei in medulla that receive auditory information from 8th cranial nerve

Superior Olivary Nucleus

Nuclei in medulla that receive auditory information from the cochlear nuclei

Lateral Lemniscus

Band of fibers carry auditory information through the medulla and pons

Medial Geniculate Nucleus

Nucleus in thalamus that relays auditory information to the primary auditory cortex

Ipsilateral, contralateral

Sound is processed via ___ , and then ___.

Hierarchal

Auditory cortex is organized in a ___ manner.

Primary Auditory Cortex

Processes pure tones (core region)

First

The ___ level of auditory association cortex is a belt region that processes complex sounds

Highest

The __ level of auditory association cortex is a parabelt region that processes complex sounds

Anterior Stream

Analysis of complex sounds (what) TO THE FRONTAL LOBE

Posterior Stream

Involved with sound location (where) TO SPACE-FOCUSED AREAS

Tonotopic Organization

Higher frequencies are located near each other and further away from lower frequencies

Rate Coding

Rate of depolarization determines LOW frequencies

Place Coding

Basilar membrane bends to determine MODERATE TO HIGH frequencies

Low

Number of axons active at the same time determine __ loudness

High

Rate of hair firing and level of tympanic membrane depressions determine __ loudness

Antibiotics

High doses may damage hair cells at base // difficulty with higher frequencies

Loud Sounds

Damage to hair cells at base

Bone Growth

Hearing loss from this over the round window

Amusia

Perception of music facts (rhythms)

Patient LR

Damaged left superior temporal gyrus; unable to perceive or produce rhythmic aspects of music

True

(T/F) Patient LR could perceive emotional aspects of music