From Vibration to Sound HEARING. Main Objective Describe the auditory sensation that results when sound waves are collected in the outer ear, amplified.

From Vibration to From Vibration to SoundSound

HEARINGHEARING

Main ObjectiveMain Objective

Describe the auditory sensation that results Describe the auditory sensation that results when sound waves are collected in the when sound waves are collected in the outer ear, amplified in the middle ear, and outer ear, amplified in the middle ear, and converted to neural messages in the ear.converted to neural messages in the ear.

Key QuestionsKey Questions

How do sound waves produce different How do sound waves produce different auditory sensations?auditory sensations?

What are the key structures of the ear and What are the key structures of the ear and their functions?their functions?

SoundSound

Sound, like light, comes in wavesSound, like light, comes in waves Sound is vibrationSound is vibration Features of sound include:Features of sound include:

PitchPitch TimbreTimbre DecibelsDecibels LoudnessLoudness FrequencyFrequency AmplitudeAmplitude

AuditionAudition

The sense of hearing.The sense of hearing. Makes you capable of responding to a Makes you capable of responding to a

wide range of sounds, from faint to blaring, wide range of sounds, from faint to blaring, simple to complex, harmonious to simple to complex, harmonious to discordant. discordant.

LoudnessLoudness The intensity (or amplitude) of a sound The intensity (or amplitude) of a sound

wave, measured in decibels. wave, measured in decibels.

AmplitudeAmplitude The The

intensity intensity or amount or amount of energy of energy of a wave, of a wave, reflected reflected in the in the height of height of the wave.the wave.

Healthy Amplitude (volume)?Healthy Amplitude (volume)?

What volume do you think is What volume do you think is okay?okay?

Not good, not bad?Not good, not bad?Handout Handout (slide 15)(slide 15)

Components of a Sound WaveComponents of a Sound Wave

Decibels (dB)Decibels (dB)

The unit of The unit of measurement measurement for loudness.for loudness.

PitchPitch A sound’s A sound’s

highness or highness or lownesslowness

Dependent on Dependent on the frequency the frequency of the sound of the sound wavewave

Is measured as Is measured as hertz (Hz)hertz (Hz)

FrequencyFrequency

Timbre (TAM-ber)Timbre (TAM-ber)

The distinctive The distinctive quality of a sound, quality of a sound, determined by the determined by the complexity of the complexity of the sound wave. sound wave.

Every human voice Every human voice had a distinct, had a distinct, unique timbre.unique timbre.

Did you know that aniPod at peak volumeIs 115 dB?

HEARING: HEARING: How We How We

Hear.Hear.The Path of SoundThe Path of Sound

Break It DownBreak It Down

Sound waves Sound waves are are collectedcollected in in the outer ear, the outer ear, amplifiedamplified in the in the middle ear, and middle ear, and transducedtransduced, , in in the inner ear.the inner ear.

Divisions of the EarDivisions of the Ear

The Outer EarThe Outer Ear

The part of the The part of the ear that collects ear that collects sound waves.sound waves.

Consists of the Consists of the pinnapinna, the , the ear ear canalcanal, and the , and the eardrumeardrum..

PINNAPINNA

It collects sound and directs it into It collects sound and directs it into the outer ear canal.the outer ear canal.

The visible part of the outer

ear.

Parts of the Ear – Auditory CanalParts of the Ear – Auditory Canal

Localization of SoundLocalization of Sound

Locating where sound is originating Locating where sound is originating fromfrom

Done through two cues:Done through two cues:Which ear hears the sound first?Which ear hears the sound first?Which ear hears the louder sound?Which ear hears the louder sound?

Localization of SoundLocalization of Sound

The opening The opening through through which sound which sound waves travel waves travel as they as they move into move into the ear for the ear for processingprocessing

Ends at the Ends at the eardrumeardrum

Auditory CanalAuditory Canal

EardrumEardrum

Also called the Also called the tympanictympanic membranemembrane. A thin membrane . A thin membrane that vibrates when sound waves that vibrates when sound waves reach it.reach it.

it transfers sound vibration from it transfers sound vibration from the air to the tiny bones of the the air to the tiny bones of the middle earmiddle ear

Can be damaged by objects in Can be damaged by objects in the ear or exceptionally loud the ear or exceptionally loud noisesnoises

The Middle EarThe Middle Ear The part of the ear that amplifies the sound The part of the ear that amplifies the sound

waves.waves. Consists of three small bones, the hammer, Consists of three small bones, the hammer,

the anvil (incus), and the stirrup (stapes).the anvil (incus), and the stirrup (stapes).

OssiclesOssicles

Three tiny bones that Three tiny bones that transfer sound waves from transfer sound waves from the eardrum to the cochleathe eardrum to the cochlea

Hammer, anvil and stirrupHammer, anvil and stirrup Fun fact: the stirrup is the Fun fact: the stirrup is the

smallest bone in the human smallest bone in the human body – only .25 cmbody – only .25 cm

THE MIDDLE EARTHE MIDDLE EAR

The Inner EarThe Inner Ear

The part of the The part of the ear where ear where sound is sound is transduced into transduced into neural impulses.neural impulses.

Consists of the Consists of the cochlea and the cochlea and the semicircular semicircular canals. canals.

CochleaCochlea

A fluid filled tube A fluid filled tube that is coiled in a that is coiled in a spiral. spiral.

Greek for Greek for snail.snail. Complex Complex

structure that is structure that is smaller than a smaller than a pea.pea.

Semicircular CanalsSemicircular Canals

Organs in the inner ear Organs in the inner ear used in sensing body used in sensing body orientation and orientation and balance (vestibular balance (vestibular sense)sense)

Relies on fluid in the Relies on fluid in the canalscanals

Spinning in circles Spinning in circles disrupts the fluid.disrupts the fluid.

Oval WindowOval Window

The point on the surface of The point on the surface of the cochlea which receives the cochlea which receives the sound vibration from the the sound vibration from the ossiclesossicles

As the oval window vibrates, As the oval window vibrates, the fluid in the cochlea the fluid in the cochlea vibrates.vibrates.

Parts of the Ear – Oval WindowParts of the Ear – Oval Window

Basilar MembraneBasilar Membrane

The membrane within the cochlea of the The membrane within the cochlea of the ear that contains the hair cells. ear that contains the hair cells.

Hair CellsHair Cells The hairlike sensory receptors for The hairlike sensory receptors for

sound, which are embedded in the sound, which are embedded in the basilar membrane in the cochlea. basilar membrane in the cochlea.

Parts of the Ear - Hair CellsParts of the Ear - Hair Cells

Auditory NerveAuditory Nerve The nerve that carries sound information The nerve that carries sound information

from the ears to the temporal lobes of the from the ears to the temporal lobes of the brainbrain

Divisions of the EarDivisions of the Ear

Review ~ What is Review ~ What is included in each included in each section?section? The outer earThe outer ear The middle earThe middle ear The inner earThe inner ear

HearingHearing

Sound comes into the ear. Sound comes into the ear. Goes through the ear Goes through the ear

canal to the eardrum.canal to the eardrum.Ear drum changes sound Ear drum changes sound

into vibrations.into vibrations.Vibrations go through Vibrations go through

middle ear to the inner ear. middle ear to the inner ear.

YOU Break It Down This Time.YOU Break It Down This Time.

Sound waves Sound waves are are ____________ in in the outer ear, the outer ear, ______________ in the in the middle ear, and middle ear, and ________________, , in in the inner ear.the inner ear.

Quiz Time!Quiz Time!