Hearing

Question 1

what is sound

Answer 1

created by vibrations which cause the molecules in a surrounding medium (air, liquid, solid) to also vibrate, resulting in pressure changes in that medium

Question 2

basic sounds can be generally defined by a _____ ____

Answer 2

sine wave

Question 3

sound requires ______ to vibrate in order to travel

Answer 3

molecules

Question 4

what medium does sounds flow through the fastest?

Answer 4

solid

Question 5

loudness is defined as (2 interchangeable terms)

Answer 5

amplitude or intensity

Question 6

amplitude/intensity

Answer 6

the magnitude of displacement of a sounds pressure wave

Question 7

frequency changes, the number of times the sound cycle repeats, are perceived as _____

Answer 7

pitch

Question 8

pitch is measured in ____; how many of these per cycle?

Answer 8

hertz; 1

Question 9

amplitude is measured in ____

Answer 9

decibels - changes in pressure ratios

distance from x axis to top of sine wave (ex. bigger wave = larger distance = louder sound)

Question 10

the upper limit of the loudness threshold is actually ____

Answer 10

pain

Question 11

our pitch threshold declines with ___

Answer 11

age

Question 12

a simple sine wave is referred to as a ___ ____ (define)

Answer 12

pure tone; defined by a single frequency

Question 13

what is the name of a display of a spectrum of energy at each frequency

Answer 13

fourier analysis

Question 14

fundamental frequency

Answer 14

how you’re breaking down the sine waves is based off of the lowest frequency wave

Question 15

timbre

Answer 15

adding harmonic frequencies in background

Question 16

how do we detect sound?

Answer 16

with shifts in molecules

Question 17

pinna

Answer 17

outer ear

evolved to help collect sound from the world, works to funnel sound into your ear canal

Question 18

another name for ear drum and what does it do

Answer 18

tympanic membrane; vibrates in response to sounds

Question 19

the middle ear consists of 3 tiny bones, called (and define)

Answer 19

ossicles; function to amplify and transmit sound to inner ear

Question 20

what are three things that make us the ossicles

Answer 20

malleus
- “hammer”; largest and one that receives vibrations from the tympanic membrane

incus
- “anvil”; connects the two ossicles

stapes
- “stirrup”; presses against the oval window of the cochlea

Question 21

a ____ shift on one side of the lever can create a ____ shift further down

Answer 21

small; larger

Question 22

tensor tympani and stapedius muscles are important for …

Answer 22

dealing with loud noises

can tense to decrease ossicle vibrations, muffle sounds, and protect the inner ear

Question 23

where does transduction happen in the ear

Answer 23

inner ear!

Question 24

the inner ear can be compared to the ____ of the eye

Answer 24

retina

Question 25

cochlea (snail)

Answer 25

the coiled structure of the inner ear has three fluid filled canals

Question 26

vestibular canal

Answer 26

receives information, extends from oval window at base of cochlea to helicotrema (center of spiral) at the apex

canal closest to ossicles and through which pressure waves move first

Question 27

tympanic canal

Answer 27

extends from the helicotrema at the apex to the round window at the base of the cohclea

Question 28

middle canal

Answer 28

sandwiched between the vestibular and tympanic canals and contains the cochlear partition

Question 29

what 2 membranes separate the canals and what canals do they separate in particular?

Answer 29

reissner’s membrane
- separate vestibular and middle canals

basilar membrane
- a plate of fibers that form the cochlear partition and separates the middle and tympanic canals

Question 30

what happens to the fluid in the canals when vibrations are transmitted?

Answer 30

they membrane of the oval window is pushed and pulled which shifts the fluid

Question 31

where does excess pressure go in the ear?

Answer 31

out through the round window

Question 32

the organ of corti

Answer 32

a structure on the basilar membrane that is composed of hair cells and dendrites of the auditory nerve fibers

where transduction takes place

Question 33

stereocilia

Answer 33

supported by the hair cells

transduce the mechanical movement of sound in the cochlea into electrochemical neural signaling

both afferent (brain receives info) and efferent (receive info from brain)

Question 34

where is the stereocilia located?

Answer 34

on the basilar membrane

Question 35

stereocilia cause changes in _____ _____ as they are flexed

Answer 35

graded potentials

Question 36

_________ from bending of the stereocilia results in neurotransmitter release to auditory nerve

Answer 36

depolarization

Question 37

_____ sounds cause more forceful mechanical shifts, thus the more forceful shearing across the _____ __ _____

Answer 37

louder; organ of corti

Question 38

place coding

Answer 38

cochlea is set up to code different frequencies across different parts of its coiled space

Question 39

what type of frequency is received further down the cochlea? what about at the base/beginning?

Answer 39

lower frequencies; higher frequencies

Question 40

inner hair cells vs. outer hair cells

Answer 40

inner
- afferent, transduce sound to send to the brain

outer
- efferent, receive information from the brain and provide feedback to the inner ear
- refine sensitivity
- adjust the tension on the membrane physically

Question 41

frequency selectivity

Answer 41

auditory nerves code for particular frequencies based on position along cochlea

Question 42

2 other influences of selectivity

Answer 42

two-tone suppression
- two tones presented at the same time result in decrease in firing rate of an auditory nerve fiber

rate saturation
- loud sounds often muddy frequencies

Question 43

isointensity curve

Answer 43

frequency vs firing rate plotted on axes and individual lines are single intensities

the louder the sound the smoother the curve

Question 44

rate-intensity function

Answer 44

reveals that some fibers require higher-intensity sounds before they fire (low-spontaneous/selectivity) and other require less (high spontaneous)

Question 45

phase locking

Answer 45

where a single neuron fires at a distinct point along a cycle of a given frequency sound wave