S&P Exam 3: Chapter 11: Hearning

What are the two diffinitions of sound?

physical definition and perceptual definition

What is the physical definition of sound?

pressure changes in the air or other medium

What is the perceptual definition?

experience we have when we hear

Sound waves are produced by __________ and ____________.

compression and rarefaction

What is rarefaction?

Occurs when particles are pulled apart, decreasing density and pressure.

What is compression?

Occurs when particles are pushed together, increasing density and pressure.

What are pure tones?

created by a sine wave

single frequency

What is frequency? How is it measured? What is it related to?

the number of cycles per second

hertz

related to pitch

What is amplitude? How is it measured? What is it related?

difference in pressure between high and low peaks of wave

measured in decibels

related to loudness

What is fundamental frequency?

repetition rate of the waveform

What are complex tones?

made up of multiple pure tones (harmonics)

What is first harmonic?

pure tone equal to the fundamental frequency

What is higher harmonics?

multiples of fundamental frequency

Spacing between harmonic indicates __________ frequency.

fundamental

________ is realted to amplitude.

Loudness

True or False: Loudness is an exponential realationship

True

What is audibility curve?

shows the threshold of hearing in relation to frequency

What is the hearing range for humans?

20 to 20,000 HZ

Humans are most sensitive to ______ - ______ hz (human speech).

2,000 - 4,000

What are equal loudness curves?

sound levels that create the same perception of loudness at different frequencies

What is tone height?

increasing fundamental frequency associated with increasing pitch

What is chroma?

same letter notes on different octaves have fundamental frequencies that are whole-number multiples of one another

What is timbre?

all other perceputal aspects of sound besides loudness, pitch, and duration

What is attack?

buildup of sound at the beginning

What is decay?

decrease in sound at the end

What is the pinnae? What does it do?

The visible, outer part of the ear is composed of skin and cartilage on the sides of the head.

Helps with sound localization,

Acts as a funnel that captures sound waves, amplifies them, and directs them into the ear canal

What is auditory canal?

protects the tympanic membrane at the end of the canal

What is resonance?

auditory canal amplies frequencies between 1,000 and 5,000 hz

What is the tympanic memebrane (eardrum)?

separtes the outer ear from the middle ear

What is are the functions of the tympanic membrane?

Vibrates in response to vibrations from the air

Transmits these vibrations to the ossicles in the

middle ear

The middle consistsis of the three ______.

ossicles

What are the ossicles?

malleus, incus, stapes

What does the malleus, incus, and stapes do?

malleus- moves due to the vibration of the tympanic membrane

incus- transmits vibrations of the malleus

stapes- transmits vibrations of incus to the inner ear via the oval window of the cochlea

What is the function of the middle ear muscles?

dampen the ossicles’ vibrations to protect the inner ear from damaging or distracting stimuli

What is the function of the ossicles?

lever action of ossicles amplify vibrations for better transmission to the cochlear fluid

True or False: The cochlea is not a part of the inner ear.

False.

The cochlea is divided into the _________ ________ and _______ _______ by the cochlear partition.

scala vestibuli and scala tympani

The _________ ________ contains structures needed to transform vibrations inside the cochlea into electrical signals (transduction)

cochlear partition

What is the function of the basilar membrane?

vibrates in response to sound and supports the organ of Corti

What are the recoptors for hearing located on the organ of corti?

inner and outer hair cells

What is stereocilia?

thin protrusions from the tops of the hair cells.

What is the tectorial membrane?

extends over the hair cells

What is phase locking?

firing of auditory neurons in synchrony with the phase of an auditory stimulus

_______ bend with rise and fall of a sound wave

cilia

Name the two ways nerve fibers signal frequency

(how fibers are firing) rate or pattern of firing of nerve impulses

(which fibers are responding) specific groups of hair cells on the basilar membrane activate a specific set of nerve fibers

What is the Bekesys Place theory of hearing?

the frequency of a sound is indicated by the place along the basilar membrane at which nerve firing is hiighest

What is the tonotopic map?

Cochlea shows an orderly map of frequencies along its length

What is Apex?

responds best to low frequncies

What is base?

responds best to high frequencies

What is characteristic frequency?

frequency to which the neuron is most sensitive

What is the cochlear amplifier

outer hair cells tilt and elongate, which amplifies and sharpens the vibration of the basilar memebrane

When outer hair cells are destroyed, the threshold for that neuron to free ________

goes way up

What two types of physiological information related to stimulus frequency help us perceive pitch

place and timing

Define place

place on cochlea where maximum firsing occurs (place coding)

Define timing

firing of auditory nerve fibers related to stimulus frequencies (temporal coding)

What is the auditory pathway in the brain

1. Auditory Nerve

2. Cochlear Nucleus

3. Superior olvary nucleus

4. Inferior colil

5. Medial geniculate nucleus

6. Primary auditory cortex

What are pitch neurons?

respond to all complex tones of the same pitch

True/False: Pitch neurons will respond to complex tones and of the same pitch and different harmonic structure

True

What is Prebycusis?

hair damage caused by noise exposure, drugs, or age-related degeneration

True/False: Prebycusis affects females more severly than males

False

True/False: Prebycusis has the greatest loss at high frequencies

True

True/False: Leisure noise cannot cause hearing loss

False

The appropraiate noise level for worker is no more than ______db/____ hr shift.

85 db/8 hr shift

True/False: Infants are born with full auditory capacity

False

2-day old infants can recongnize their mother’s _____ and prefer her _______ _______.

voice; native language

Discuss how sound waves are produced through rarefaction and compression.

A sound wave occurs when movements or vibrations of an object cause pressure changes in air, water, or any other elastic medium that can transmit vibrations.

In speaking, when the diaphragm of the speaker moves out, it pushes the surrounding air molecules together. This process is called compression. Compression causes a slight increase in the density of the surrounding molecules near the diaphragm. This increase in density causes the air pressure to rise above the atmospheric pressure.

When the diaphragm moves back in, the air molecules spread out. This process is called rarefaction. Rarefaction causes a slight decrease in the density of the surrounding molecules.

The pattern of air pressure changes that travels at 340 meters per second creates a sound wave.

What is a pure tone? Are pure tones common in the natural world?

a simple kind of sound wave

occurs when changes in air pressure occur in a pattern described by a mathematical function called a sinewave

Pure tones are not commonly found in the natural word (only occasionally)

What is the frequency of sound waves related to? How are they measured?

the number of cycles per second that the change in pressure repeats

it is measured hetz

it is related to pitch

What is the amplitude of sound waves related to? How are they measured? Describe why there is an exponential relationship between amplitude and our perception of loudness.

The difference in pressure between the high and low peaks of the wave

measured in decibels (dB)

related to loudness

The relationship is exponential (logarithmic) because sound intensity is proportional to the square of the amplitude, and the human ear perceives loudness exponentially to manage a massive range of sound pressures.

Describe complex tones, including their fundamental frequency and harmonics.

sound waves comprised of multiple frequencies (multiple pure tones) rather than a single sine wave.

Consists of a fundamental frequency, which is the lowest frequency, and a series of harmonics, which are multiples of the fundamental.

What range of frequencies can be perceived by humans? Which range of frequencies are humans most sensitive to?

Humans are most sensitive to 2,000 - 4,000 Hz

Human hearing range - 20 to 20,000 Hz

Define tone height and tone chroma in relation to timbre.

Tone height = increasing fundamental frequency associated with increasing pitch

Tone chroma = same letter notes on different octaves have fundamental frequencies that are whole-number multiples of one another

Describe the process of auditory transduction.

Vibration of eardrum

Vibration of middle ear bones

Vibration of oval window

Movement of Fluid in Cochlea

Vibration of basilar membrane

Receptor hair cells bend

Influx of K+ ions into receptor har cells

Receptor hair cells voltage becomes positive

Increased action potentials generated in auditory nerve

Action potentials relayed to the brain

Hearing occurs

Describe which information the brain uses to help us percieve pitch.

– Place – place on cochlea where maximum firing occurs (place coding)

– Timing – firing rate of auditory nerve fibers related to stimulus frequencies (temporal coding)

List each component of the auditory pathway in the brain.

Auditory Nerve

Cochlear nucleus

Superior olivary nucleus

Inferior colliculus

Medial geniculate nucleus

Primary auditory cortex

Describe the common causes of hearing loss. How can hearing loss be treated or prevented?

Prebycusis: Hair cell damage caused by noise exposure, drugs, or age-related degeneration

Leisure noise can also cause hearing loss

• MP3 players, concerts, sporting events, motorcycles

OSHA standards for noise levels at work are set to protect workers

• No more than 85 db/8 hr shift

cochlear implant

Hearing Aid

Define timbre and how attack and decay are related to timbre.

Timbre - all other perceptual aspects of

sound besides loudness, pitch, and duration

• Attack- buildup of sound at beginning

• Decay- decrease in sound at end

Essentially, without attack and decay, a piano and a trumpet playing the same note might sound similar; these elements provide the "identity" that helps us differentiate between instruments