Hearing, Balance, Smell, and Taste

Question 1

Pure tone is described by two measures

Answer 1

Amplitude and frequency

Question 2

Amplitude

Answer 2

Intensity, perceived as loudness

Question 3

Frequency

Answer 3

Number of cycles per second of vibration

Question 4

Most sounds are more complicated than a pure tone

Answer 4

A sound contains a fundamental, or basic, frequency—harmonics are multiples of that frequency

Question 5

Sound, a mechanical force, is ______ into neural activity in the ear

Answer 5

transduced

Question 6

The external ear and the pinna…

Answer 6

capture and funnel sound waves into the ear canal

Question 7

What are the ridges and valleys of the external ear for?

Answer 7

Modify sound frequencies
Important for vertical location

Question 8

Function of the middle ear

Answer 8

concentrates sound energies

Question 9

The three ossicles that connect the tympanic membrane (eardrum) to the oval window of the inner ear

Answer 9

Malleus, incus, and stapes

Question 10

What do the ossicles do?

Answer 10

They move when sound waves strike the tympanic membrane

They concentrate and amplify the vibrations on the oval window

Question 11

What do the two muscles in the middle ear do?

Answer 11

Improve auditory perception, protect the inner ear from potentially damaging sounds, and minimize self-made sounds

Question 12

Tensor tympani

Answer 12

Attached to the malleus and tympanic membrane

Question 13

Stapedius

Answer 13

Attached to the stapes

Question 14

What do inner ear structures do?

Answer 14

Convert sound into neural activity

Question 15

Three parallel canals of the cochlea

Answer 15

Scala vestibuli—vestibular canal
Scala media—middle canal
Scala tympani—tympanic canal

Question 16

Organ of Corti

Answer 16

In the scala media

Receptor system that converts vibration from sound into neural activity

Question 17

The vestibulocochlear nerve

Answer 17

Cranial nerve VIII; contains auditory fibers from the cochlea

Question 18

Each auditory nerve fiber divides into two branches

Answer 18

Go to cells in the ventral or dorsal cochlear nuclei

Question 19

Output of the cochlear nuclei travels to multiple targets

Answer 19

To the superior olivary nuclei OR inferior colliculi
——>
Then to the medial geniculate nuclei
——>
And finally to the auditory cortical areas

Question 20

Superior olivary nuclei

Answer 20

Brainstem
Receive bilateral input
Helpful for identifying location of sound

Question 21

Inferior colliculi

Answer 21

In the midbrain
The primary auditory centers of the brain

Question 22

Medial geniculate nuclei

Answer 22

In the thalamus

Question 23

How can you tell where a sound comes from?

Answer 23

Binaural cues signal sound location

Question 24

Intensity differences

Answer 24

Differences in loudness at the two ears (the head can cause a sound shadow)

Question 25

Latency differences

Answer 25

Differences between the two ears in the time of arrival of sounds

Question 26

What about identifying location of sound in a vertical plane?

Answer 26

Spectral filtering Important in bats for echolocation

Question 27

Spectral filtering

Answer 27

The pinna selectively reinforces some frequencies and reduces others

Question 28

Three main causes of hearing loss and deafness

Answer 28

Conduction deafness Sensory-neural deafness Central deafness

Question 29

Conduction deafness

Answer 29

Disorders of the outer or middle ear that prevent sounds from reaching the cochlea

Question 30

Sensory-neural deafness

Answer 30

A problem in the cochlea that interferes with the transduction of sound vibrations into neural activity

Question 31

Central deafness

Answer 31

Damage to auditory brain areas, such as by stroke, tumors, or traumatic brain injury

Question 32

Ototoxic effects

Answer 32

Ear-damaging effects that may be due to drugs, such as streptomycin

Question 33

Tinnitus

Answer 33

Ringing in ears from damaged hair cells

Question 34

Cochlear implants

Answer 34

Used to treat deafness due to hair cell loss Electrical currents stimulate the auditory nerve

Question 35

Vestibular system

Answer 35

Detects position and movement of the head

Question 36

Semicircular canals

Answer 36

Three fluid-filled tubes in different planes

Question 37

An inner ear system senses gravity and acceleration

Answer 37

Movement of the head in any one axis sets up a flow of fluid in the semicircular canal, deflecting the stereocilia in the ampulla and signaling the to brain that the head has moved

Question 38

Movements of the head involve rotation around the 3 principal axes

Answer 38

The pitch axis, the yaw axis, and the roll axis

Question 39

Main adaptive role of the chemical senses

Answer 39

Evaluation of potential food in natural environments

Question 40

Olfaction (smell)

Answer 40

Detects airborne chemicals

Question 41

Gustation (taste)

Answer 41

Responds to chemicals in the mouth

Question 42

Food acts on both systems to produce _______

Answer 42

flavor

Question 43

Olfactory epithelium

Answer 43

Receptor neurons in the nose for smell

Question 44

Turbinates

Answer 44

Help direct air flow in nose into the olfactory epithelium where olfactory sensory neurons are

Question 45

Mammalian odor detection relies on...

Answer 45

olfactory sensory neurons

Question 46

What happens once olfactory receptor cells are activated?

Answer 46

Once at a receptor cell, odorants interact with receptors on the cilia and dendritic knob

Question 47

What happens once receptors on cilia and dendritic knob are activated?

Answer 47

The G protein is activated, triggering production of second messengers

Question 48

Olfactory receptor cell axons end in the...

Answer 48

olfactory bulb

Question 49

Glomeruli

Answer 49

The olfactory bulb is organized into many glomeruli Spherical units that pass information from similar types of OSNs to mitral cells in the olfactory bulb

Question 50

After the mitral cells...

Answer 50

The smell information goes directly to the primary olfactory cortex (and some other brain regions)

Question 51

Smell is the only sense that does not send information through the _______ for processing

Answer 51

thalamus

Question 52

If the olfactory epithelium is damaged....

Answer 52

It can be regenerated and will properly reconnect to the olfactory bulb

Question 53

True or false? Taste is localized to specific parts on the tongue

Answer 53

False There are different proportions of different types of receptors throughout the tongue, but they’re all capable of detecting taste

Question 54

Papillae

Answer 54

Bumps on our tongues Taste buds are on sides of the papillae

Question 55

Three kinds of taste papillae are distributed on the tongue

Answer 55

Circumvallate papillae Foliate papillae Fungiform papillae

Question 56

Each papilla holds multiple taste buds, each of which consists of ______ taste receptor cells

Answer 56

50-100

Question 57

Taste pore

Answer 57

Taste cells extend cilia into the taste pore, the opening at the surface of the taste bud

Question 58

Tastants

Answer 58

Taste pores open to receive tastants

Question 59

Salty

Answer 59

Sodium (Na+) ions are transported across taste cell membranes, causing depolarization that sends information to the brain

Question 60

Sour

Answer 60

All acids release hydrogen ions (H+) The more acidic the food, the more sour it tastes This same receptor detects carbonation in drinks

Question 61

Receptors for sweet, bitter, and umami

Answer 61

All appear to stimulate G-protein coupled receptors that cause a cascade of intracellular events

Question 62

1st step of taste transduction

Answer 62

Tastants bind to corresponding receptors on taste cell

Question 63

2nd step of taste transduction

Answer 63

Multiple intracellular pathways are activated

Question 64

3rd step of taste transduction

Answer 64

Ca2+ triggers transmitter release

Question 65

4th step of taste transduction

Answer 65

Neurotransmitter is released, and primary sensory neuron fires

Question 66

5th step of taste transduction

Answer 66

Action potentials are sent to the brain

Question 67

Supertasters

Answer 67

Heightened sensitivity to some bitter and sweet tastes, suggesting that they are genetically different

Question 68

Each taste cell reacts to...

Answer 68

one kind of taste

Question 69

Taste info is conveyed via several cranial nerves to...

Answer 69

nuclei in the brainstem and then to the thalamus

Question 70

From the thalamus, a taste-specific pathway projects to...

Answer 70

Cortical taste areas

Question 71

Cortical taste areas

Answer 71

Give us our conscious perception of tastes