Topic 9- The auditory system Flashcards by Allyssia Mcdonald

What are the two definitions of hearing?

8pts

Physical definition:
- Does the sound happen even if someone isn’t present ?
- Sound is pressure changes in the air (or other medium)
- “The sound of the trumpet has a frequency of 1000hz”

Perceptual definition:
- What if no one is present?
- Sound is the experience we have when we hear
- “The sound of the trumpet filled the room”

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When does a physical sound stimulus occur?

A physical sound stimulus occurs when the movement or vibrations of an object causes pressure changes in air, water, etc

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What happens when a speaker vibrates ?

When a speaker vibrates it affects the surrounding air and produces both increases and decreases in pressure.

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What is compression in a speaker?

When the speaker moves out, it pushes air molecules closer together and increases air pressure

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What is rarefaction in a speaker?

When the speaker moves back in, air molecules spread back out and decreases air pressure

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By repeating compression and rarefaction hundreds of times per second, this process produces a …

A sound wave

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What is a pure tone?

A tone that can be described by a single sine wave

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What is frequency? What is it measured in?
3pts

Number of cycles per second the pressure change occurs
Number of “repeats”
Measured in Hz

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What is amplitude? What is it measured in?

3pts

The size of pressure change that occurs
Difference between the peak and valley of the sine
Measured in dB

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Are pure tones or complex tones rare?

Most environmental sounds are what type of tones?

2pts

Pure tones are rare
Most environmental sounds are complex tones ( Made up of several pure tones that are added together)

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What are the 3 perceptual dimensions of sound?

3pts

Loudness (volume/intensity)
Pitch
Timbre

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The smallest amount of sound energy that can just barely be detected

Threshold or loudness? Give an example.

Threshold
“Can you hear it?”

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The perceived intensity of a sound that ranges from “very quiet” to “very loud”

Threshold or loudness? Give an example.

2pts

Loudness
“How loud does it sound?”

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What is loudness? What is it closely related to?

BLANK dB is considered the absolute threshold for human hearing
–> Assuming normal functioning

Intensities above ~BLANK dB can cause permanent damage to the sensory receptors inside our ears

The perceptual quality most closely related to the amplitude of an auditory stimulus
0
120

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In the human audibility curve, we hear sounds within a specific range of frequencies, which area signifies the auditory response area

The green area

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We are most sensitive to sounds between BLANK and BLANK Hz.

What does this signify ?

2pts

2000Hz and 5000Hz
This is around the frequency of human speech

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What is pitch?

3pts

high vs low perception of sound
closely related to the physical characteristics of frequency
tied to the number of repetitions

What is the pitch (high or low) and volume (soft or loud)? Give an example.

Low frequency, low amplitude?

a. bird chirping
b. fire alarm
c. faucet dripping
d. lawnmower

3pts

Low pitch
Soft volume
Faucet dripping

What is the pitch (high or low) and volume (soft or loud)? Give an example.

Low frequency, high amplitude.

a. bird chirping
b. fire alarm
c. faucet dripping
d. lawnmower

3pts

Low pitch
Loud volume
Lawnmower

What is the pitch (high or low) and volume (soft or loud)? Give an example.

High frequency, low amplitude.

a. bird chirping
b. fire alarm
c. faucet dripping
d. lawnmower

3pts

high pitch
soft volume
bird chirping

What is the pitch (high or low) and volume (soft or loud)? Give an example.

High frequency, high amplitude.

a. bird chirping
b. fire alarm
c. faucet dripping
d. lawnmower

3pts

high pitch
loud volume
fire alarm

What is timbre?

Distinguishes the difference between two tones with the same loudness and pitch but sound perceptually different

During the process of hearing, the auditory system accomplishes 3 things, what are they?

3pts

Delivers the sound stimuli to the sensory receptors
Transduces the stimulus from pressure changes to electrical activity
Processes this electrical activity to create the perceptual qualities of the sound

Rather, changes in air pressure cause BLANK in the structures within our BLANK system that then get transferred from structure to structure

What are the 3 structures the areas of the ear sound travels down?

4pts

-Vibrations, auditory

outer ear, middle ear, inner ear

What is the function of the outer ear? 3pts

- Sound waves first bounce around the pinna then enter to auditory canal - This canal along with the wax inside, help protect the more delicate structures of the middle ear - Also serves to slightly increase the amplitude of some sound frequencies, particularly those used for speech

What separates the outer and middle ear?

The tympanic membrane

What is the function of the middle ear? 5pts

- Small cavity that separates the outer and inner ear - Contains the ossicles- the 3 smallest bones in the human body 1. Malleus (hammer) 2. Incus (anvil) 3. Stapes (stirrup)

BLANK & BLANK ear are filled with air, but BLANK ear contains watery liquid (BLANK fluid)

Outer, middle, inner, cochlear

What do the ossicles serve to do? What happens after? 2pts

- Serve to concentrate the vibrations from the large tympanic membrane onto the small surface of the stapes - Stapes then pass on these vibrations to the oval window in the inner ear

What is the main structure of the inner ear?

- The main structure is the liquid filled cochlea- a long, coiled tube, giving a snail like appearance

What does the organ of Corti contain/do?

- Inner ear structure that contains the hair cells - the sensory receptors for hearing

The organ of Corti sits on top of the BLANK membrane and is covered by the BLANK membrane The organ has both BLANK and BLANK BLANK cells What am I and where am I located: These are embedded in the tectorial membrane and will bend in response to vibration. Bending of the hair cells causes BLANK to occur.

- basilar, tectorial - inner, outer, hair - tips of the hair cells, called stereocilia - transduction

How does our nervous system learn anything about the sound’s pitch? What does it involve?

- involves looking at how the basilar membrane vibrates in response to different frequencies

Frequency representation: Pitch When you look at the BLANK membrane from base to apex, there is a difference in where the BLANK bending occurs Apex = ... Base = ... This is the BLANK membrane’s BLANK map

- basilar, maximum - low frequencies, high frequencies - basilar, tonotopic

Knowing the tonotopic organization of the basilar membrane allows for BLANK implants Implanted surgically in the inner ear to convert sound BLANK to BLANK activity and allows some deaf people to hear Detects BLANK of sound waves and sends them to their appropriate place on the BLANK membrane using tiny BLANK

- Cochlear - waves, electrical - frequencies, basilar, electrodes

The greater the amplitude of the incoming sound, the more BLANK that occur, and the...

- vibrations, higher the firing rate of the hair cells in the cochlea

Signals generated by the hair cells...

Signals generated by hair cells are transmitted out the cochlea by the auditory nerves, along the auditory pathway, eventually reaching the primary auditory cortex (A1)

What is hearing loss normally associated with damage to? 3pts

hair cells or cortical or auditory nerve damage

Hearing loss caused by hair cell damage resulting from: The cumulative effects of noise over time (at normal levels) The ingestion of ototoxic drugs (strong antibiotics, cancer/heart disease meds, also NSAIDs) Age-related degeneration The loss of sensitivity associated with this is greatest at high frequencies and tends to affect males more severely than females. What type of hearing loss is this?

Presbycusis

Loss that occurs when loud noises cause degeneration of the hair cells High-intensity sounds can damage or completely destroy them Often a direct result of high volumes of work or leisure noise What type of hearing loss is this?

noise-induced hearing loss