Auditory System

Question 1

Sound wave

Answer 1

A sound stimuli that causes the air to vibrate to compress and decompress air molecules as a sound wave

Question 2

Amplitude

Answer 2

The greater the wave height, the louder the sound

Question 3

Frequency

Answer 3

The shorter the wavelength, the higher the pitch

Question 4

Pure tone

Answer 4

A sound consisting of only a single frequency

Question 5

Complex tone

Answer 5

A sound consisting of multiple frequencies with multiple underlying patterns (ex: human speech)

Question 6

What is the human hearing frequency sensitivity?

Answer 6

Between 1000 and 4000 Hz is the optimal sensitivity, which aligns with the greatest range for human speech

Question 7

Structures of the outer ear

Answer 7

Pinna, ear canal, tympanic membrane

Question 8

Pinna

Answer 8

External cartilage that collects sound

Question 9

Ear canal

Answer 9

The tube that funnels and concentrates energy and mildly amplifies sound

Question 10

Tympanic membrane

Answer 10

The membrane that vibrates in response to sound and transfers this energy to the inner ear

Question 11

Structures of the middle ear

Answer 11

Ossicles, tensor tympani, stapedius

Question 12

Ossicles

Answer 12

Hammer, anvil stirrup; bones that vibrate in response to energy to transfer and amplify energy

Question 13

Tensor tympani and stapedius

Answer 13

Muscles that stiffen the ossicles and pull the stirrup back to protect against loud sounds

Question 14

Structures of the inner ear

Answer 14

Cochlea, oval window

Question 15

Oval window

Answer 15

The location on the cochlea where energy is transferred from the ossicles to inside the cochlea

Question 16

Cochlea

Answer 16

Fluid-filled cavity that produces nerve impulses in response to sound energy

Question 17

Structures of the cochlea

Answer 17

Organ of Corti, hair cells, basilar membrane, tectorial membrane

Question 18

Organ of Corti

Answer 18

A structure containing hair cells on the basilar membrane that converts sound vibrations to neural signals

Question 19

Hair cells

Answer 19

Hearing receptor cells where transduction occurs in the cochlea

Question 20

Basilar membrane

Answer 20

The membrane containing hair cells

Question 21

Tectorial membrane

Answer 21

A gel-like membrane that stimulates hair cells

Question 22

Sound transference and amplification process

Answer 22

1. Compressed and decompressed air moves to the pinna and funnels through the ear canal
2. Tympanic membrane vibrates, which passes the vibrations through the ossicles
3. The vibration reaches the cochlea to make the fluid inside move in waves
4. The basilar membrane vibrates which activates hair cells to transduce movements of the basilar membrane
5. Hair cells connect to the vestibulocochlear nerve which sends the electrical signal to the brain

Question 23

How is volume registered?

Answer 23

By the number of hair cells activated

Question 24

Place coding

Answer 24

Each frequency activates a certain area of hair cells so that the CNS responds based on which neurons respond

Question 25

Frequency/ temporal coding

Answer 25

Auditory nerve axons produce action potentials at the same frequency of the basilar membrane vibrations

Question 26

Volley principle

Answer 26

Gets all cells to work together to extend their firing rate to be able to hear high frequencies

Question 27

Tonotopic organization

Answer 27

The center (apex) signals low frequency while the end (base) signals high frequency

Question 28

Where does tonotopic organization occur?

Answer 28

The basilar membrane, auditory neuron, cochlear neurons

Question 29

Auditory neural pathway

Answer 29

1. Bipolar spiral ganglion cell generates an action potential
2. The action potential travels from the basilar membrane to the first synapse on the cochlear nucleus
3. The action potential travels to second synapse on the superior olivary nucleus
   4: Input from the left and right ears are shared to the same and opposite olivary nuclei
4. The action potential third synapses on the inferior colliculus
5. The action potential fourth synapses on the medial geniculate nucleus of the thalamus
6. The thalamus sends information to the auditory cortex

Question 30

Sound localization

Answer 30

The ability to determine where a sound is coming from

Question 31

Interaural time difference

Answer 31

A difference in the time a sound reaches both ears

Question 32

Interaural intensity difference

Answer 32

A difference in the volume that each ear detects

Question 33

What directions of sound do we have trouble locating?

Answer 33

Front, back, directly above

Question 34

How do we fix disparity in sound localization?

Answer 34

Our vision can be used to help clarify the sound source by seeing the source itself

Question 35

How does the auditory cortex organize sound?

Answer 35

By frequency and tonotopically

Question 36

Anterior auditory pathway

Answer 36

The path from the medial geniculate nucleus to the prefrontal and auditory cortex to understand WHAT a sound is

Question 37

Posterior auditory pathway

Answer 37

The path from the medial geniculate nucleus to the posterior temporal lobe and parietal cortex to understand WHERE a sound comes from

Question 38

Conduction deafness

Answer 38

A problem with the transference of vibration in the ossicles, preventing sound to reach the cochlea

Question 39

Sensorineural deafness

Answer 39

Damage to hair cells or to the auditory nerve so that hair cells fail to fire an action potential or the action potential cannot reach the cortex

Question 40

Central deafness

Answer 40

Damage to the auditory cortex affect hearing in many ways

Question 41

What does loud noise do?

Answer 41

Hair cells in the cochlea become crushed and flattened to result in deafness from corresponding frequencies