CHAPTER 9

Question 1

Sounds are created when____

Answer 1

objects vibrate

Question 2

what are physical qualities of soundwaves?

Answer 2

1. amp/ intensity
   
   • LOUDNESS (perceived)
   • magnitude
2. Frequency
   
   • # of times per sec that

     a pattern of pressure 
     change repeats 

   • PITCH (perceived)

Question 3

what are the units for measuring sound

Answer 3

1. Hz
   measure for frequency
2. dB
   measure for physical intensity

Question 4

__________ defines the diff between 2 sounds as the ratio between two sound pressures

Answer 4

Decibels

Question 5

what are the psychological qualities of soundwaves

Answer 5

loudness
pitch

Question 6

_______ frequency corresponds to low pitches

Answer 6

low,low

Question 7

_______ frequency corresponds to ________ pitches

Answer 7

high, high

Question 8

true or false an increase in 6 dB corresponds to a doubling of the amount pressure

Answer 8

true because small decibel changes can correspond to large physical changes

Question 9

to describe differences in AMP sound levels are measured on a ______ scale in ________

Answer 9

logarithmic scale
dB

Question 10

label the following sound intensities from smallest threshold of hearing to largest

jet take off
jackhammer
business office
heavy truck
leaves rustling
library

Answer 10

leaves rustling
library
business office
heavy truck
jackhammer
jet take off

Question 11

one of the simplest kinds of sounds are _____ or ______

Answer 11

sine waves or pure tone

Question 12

______ : the waveform for which variation as a function of time s a sine function

Answer 12

sine wave

Question 13

true or false sine waves are common everyday sounds

Answer 13

false because not many vibrations in the world are so pure

Question 14

T/F all sound waves can be described as some combo of sine waves

Answer 14

true

Question 15

complex sounds are best described as a ______

Answer 15

spectrum

Question 16

_______: the spectrum of a complex sound in which energy is at integer multiples of the fundamental frequency

Answer 16

In simple terms, a HARMONIC SPECTRUM refers to the different sound frequencies that make up a complex sound. Imagine you play a note on a musical instrument, like a piano or a guitar. The main pitch you hear is called the fundamental frequency. However, there are also additional, higher-pitched sounds (harmonics or overtones) that occur at exact multiples of that fundamental frequency.

Question 17

describe a fundamental frequency.

Answer 17

These frequencies follow a pattern: the lowest one is the fundamental frequency, and all the others are integer multiples of it (harmonics).

If a guitar string vibrates at 200 Hz, that’s the fundamental frequency.
Other vibrations at 400 Hz, 600 Hz, 800 Hz (harmonics) occur too, but 200 Hz is the lowest and determines the main pitch you hear.

Question 18

_____: the psychological sensation by which a listener can judge that 2 sounds with the same loudness and pitch are dissimilar

quality is conveyed by harmonics + other high frequencies

Answer 18

Timbre

Question 19

what is the basic structure characteristics of the outer ear ?

Answer 19

PINNA: where sounds are first collected from the environment

EAR CANAL: where sounds from pinna get funnelled to the tympanic embrane
- enhanced by certain sound freq
- also protects the tympanic membrane

TYMPANIC MEMBRANE:
- the eardrum
- thin sheet of skin
- vibrates w/ sound
- border of outer and middle ear

Question 20

true or false puncturing your ear drum will lead to hearing loss

Answer 20

false in MOST cases it will heal itself however it is possible to damage it beyond repair

Question 21

what is the basic structure characteristics of the middle ear?

Answer 21

the ossicles:
- malleus
- incus
- stapes (smaller surface = sound energy is concentrated)

middle ear muscles:
- Tensor Tympani
- Stapedius

all these amplify and transmit sounds to the inner ear

important especially for faint sounds + loud sounds

Question 22

______ and _______ are two muscles in the middle ear that decrease ossicle vibrations when tensed. protect the inner ear by muffling loud sounds (not abrupt sounds (gun shots))

Answer 22

Tensor Tympani
Stapedius

Question 23

what is the basic structure characteristics of the inner ear?

Answer 23

Cochlea: spiral structure containing the organ of corti

filled w/ endolymph + perilymph (watery fluids

Question 24

what are three canals of the cochlea

Answer 24

1. vestibular canal: oval window to helicotrema
2. tympanic canal: helicotrema to round window
3. middle canal: sandwiched between vestibular and tympanic canals + contains the cochlear partition

Question 25

the three cochlear canals are separated by ?

Answer 25

Reissner's membrane - separating vestibular and middle canals in the cochlea basilar membrane" - base of cochlear partition - separates middle and tympanic canals

Question 26

the organ of Corti: ___________

Answer 26

a structure of the basilar membrane of the cochlea that us composed of hair cells + dendrites of auditory nerve fibres

Question 27

movements of ________ are translated into neural signals by structures in the organ of Corti

Answer 27

Cochlear Partition

Question 28

_________: a gelatinous structure, attached on one end, that extends into the middle canal of the ear, floating above inner hair cells + touching outer hair cells

Answer 28

Tectorial Membrane

Question 29

________: hairlike extensions on the tips of hair cells in the cochlea that, when flexed, initiate the release of NT

Answer 29

Sterocilia

Question 30

what connects the tip of each stereo cilium

Answer 30

tiny filament called tip link

Question 31

________: Different parts of the cochlea respond to different sound frequencies. The location with the most movement tells the brain the sound's pitch.

Answer 31

place code

Question 32

__________ frequencies displace basilar membrane in base of cochlea

Answer 32

high

Question 33

__________ frequencies displace basilar membrane in apex of cochlea

Answer 33

low

Question 34

what are some differences between inner and outer hair cells

Answer 34

inner: - convey almost all info - use afferent fibres - feedback from outer hair cells make inner hair cells more sensitive/ sharply tuned. outer: - receive info from brain - use efferent fibres - involve feedback system (this can make parts of cochlear partition stiffer)

Question 35

T/F responses of individual AN fibres to diff freq are related to their place along the cochlear partition

Answer 35

true

Question 36

________: graph that shows the lowest sound level (threshold) needed to activate the nerve at each frequency.

Answer 36

threshold tuning curve

Question 37

what is two-tone supression?

Answer 37

is when the response of an auditory nerve fiber to a sound (tone 1) is reduced when a second sound (tone 2) is played at the same time. It helps the ear process complex sounds by reducing unnecessary background noise and improving contrast between important frequencies.

Question 38

T/F? auditory nerve fibers are less selective for their characteristic frequencies at levels well above threshold compared to barely audible sounds

Answer 38

TRUE: Isointensity curves show how an AN fiber responds to different frequencies at a fixed sound level. At low intensities (near threshold), the fiber responds most strongly to its characteristic frequency (CF) and much less to other frequencies. However, at higher intensities, the fiber starts responding to a broader range of frequencies, reducing its frequency selectivity.

Question 39

______: The point at which a nerve fibre is firing as rapidly as possible and further stim is incapable of increasing the firing rate

Answer 39

rate saturation

Question 40

________: shows how the firing rate of an auditory nerve (AN) fiber changes as sound intensity (dB SPL) increases.

Answer 40

The Rate-Intensity Function (RIF)