Neuroscience 2 - Audiovestibular

Front 1

The sense of balance is regulated by the ___ system

Back 1

Vestibular

Front 2

The speed of sound is about ___ m/sec for air at room temperature

Back 2

343

Front 3

The frequency of the sound is the number of ___ patches of air that pass by our ears each second, and the ___ is the difference between them

Back 3

Compressed or rarefied, intensity

Front 4

___ can hear higher frequency sounds, while __ can hear lower

Back 4

Bats and dogs, elephants and whales

Front 5

Intensity is the difference in ___ between compressed and rarefied patches of air

Back 5

Pressure

Front 6

The visible portion of the ear consists primarily of cartilage covered by skin, which forms a sort of funnel called the ___, the entrance to the internal ear is called the___, and it ends at the ___

Back 6

Pinna, auditory canal, tympanic membrane

Front 7

Connected to tympanic membrane is a series of bones called ___, which transfer movements into the ___, behind which is the ___

Back 7

Ossicles, oval window, cochlea

Front 8

The auditory signal is transferred to and processed by a series of nuclei in the ___. Output from these nuclei is sent to a relay in the ___, the __. Finally, the MGN projects to ___, located in the ___ lobe.

Back 8

Brain stem, thalamus, medial geniculate nucleus, primary auditory cortex (A1), temporal

Front 9

The ossicle attached to the tympanic membrane is the ___, which forms a rigid connection with the ___, which forms a flexible connection with the ___

Back 9

Malleus (hammer), incus (anvil), stapes (stirrup)

Front 10

The ___ in the middle ear is continuous with the nasal cavities via the ___

Back 10

Air, Eustachian tube

Front 11

The middle ear increases pressure at the oval window by the ___ and ___, combining to make the pressure at the oval window about __ times greater

Back 11

Ossicles acting like levers, surface area being smaller, 20

Front 12

The ___ muscle and the ___ muscle react to the onset of a loud sound in a response called the ___.

Back 12

Tensor tympani, stapedius, attenuation reflex

Front 13

Purposes of attenuation reflex: ___[4]

Back 13

Adapt to high intensity sound, protect from damage, may allow hearing speech better, don’t hear own voices

Front 14

The central pillar of the cochlea is a conical bony structure called the ___. At the base of the cochlea are the oval window and the ___.

Back 14

Modiolus, round window

Front 15

The cochlea is subdivided into sections separated by membranes: __[5]

Back 15

Scala vestibuli, Reissner’s membrane, scala media, basilar membrane, scala tympani

Front 16

Sitting on the basilar membrane is the ___, which contains auditory receptor neurons; hanging over this organ is the ___

Back 16

Organ of Corti, tectorial membrane

Front 17

At the apex of the cochlea, the ___ is closed off, and the other two sections become continuous at a hole in the membranes called the ___

Back 17

Scala media, helicotrema

Front 18

The fluid in the scala vestibuli and scala tympani, called___ , has an ionic content similar to that of ___: low ___ and high ___

Back 18

Perilymph, cerebrospinal fluid, K+, Na+

Front 19

The scala media is filled with ___, which is an unusual extracellular fluid in that it has ionic concentrations similar to ___, due to active transport processes taking place at the ___

Back 19

Endolymph, intracellular fluid, stria vascularis

Front 20

The endolymph has an electrical potential that is about 80 mV more ___ than that of the perilymph; this is called the ___

Back 20

Positive, endocochlear potential

Front 21

The basilar membrane has two structural properties that determine the way it responds to sound: ___[2]

Back 21

membrane is wider at the apex than at the base; stiffness of the membrane decreases from base to apex

Front 22

If the frequency is high, the base of the basilar membrane will vibrate ___, and the wave will ___

Back 22

a good deal, not propagate very far

Front 23

If the frequency is low, the base of the basilar membrane will vibrate ___, and the wave will ___

Back 23

Little, propagate farther

Front 24

The auditory receptor cells, which convert mechanical energy into ___ are located in the ___

Back 24

a change in membrane polarization, organ of Corti

Front 25

The auditory receptors are called ___ because each one has about 100 hairy-looking ___ extending from its top

Back 25

Hair cells, stereocilia

Front 26

The hair cells are sandwiched between the ___ and a thin sheet of tissue called the ___. The ___ span these two membranes and provide structural support.

Back 26

Basilar membrane, reticular lamina, rods of Corti

Front 27

Hair cells between the ___ and the ___ are called inner hair cells , and cells farther out than the ___ are called outer hair cells

Back 27

Modiolus, rods of Corti, rods of Corti

Front 28

The stereocilia extend above the ___ into the ___, and their tips end in the gelatinous substance of the ___

Back 28

Reticular membrane, endolymph, tectorial membrane

Front 29

The ___ is at the base of the organ of Corti, the ___ forms a roof over the structure, and the ___ in the middle, holding onto the hair cells

Back 29

Basilar, tectorial, reticularis

Front 30

Hair cells form synapses on neurons whose cell bodies are located in the ___within the ___. Spiral ganglion cells are ___, with neurites extending to the bases and sides of the hair cells, where they receive synaptic input.

Back 30

spiral ganglion, modiolus, bipolar

Front 31

Axons from the ___ enter the auditory nerve, a branch of ___, which projects to the ___ in the ___

Back 31

Spiral ganglion, cranial nerve VIII, cochlear nuclei, medulla

Front 32

A cochlear implant has ___ separate stimulation sites that allow it to activate the ___

Back 32

8-22, auditory nerve

Front 33

How hair cells react to bending of stereocilia: __

Back 33

Depolarizing in one direction and hyperpolarizing in the other

Front 34

There is a special type of cation channel, the ___, on the tips of the ___, are induced to open and close by the bending of stereocilia, thereby generating changes in the hair cell ___

Back 34

TRPA1 channel, stereocilia, receptor potential

Front 35

Each TRPA1 channel is connected by an elastic filament, called a ___, to the wall of the adjacent cilium. When the cilia are straight, the tension on the tip link holds the channel in a partially opened state, allowing a small leak of __ from the endolymph into the hair cell

Back 35

Tip link, K+

Front 36

Unlike in most cells, the opening of __ channels produces a ___ in the hair cell. The reason that hair cells respond differently than neurons is ___

Back 36

K+, Depolarization, high K+ concentration in endolymph

Front 37

The ___ neurons, which are the first in the auditory pathway to fire action potentials, provide all the auditory information sent to the brain

Back 37

Spiral ganglion

Front 38

Outer hair cells are ___ more common than inner hair cells, but spiral ganglion cells receive ___ of input mostly from the inner hair cells

Back 38

3, 95%

Front 39

__ seem to act like tiny motors that amplify the movement of the ___ during low-intensity sound stimuli. Because of this, they are referred to as the __

Back 39

Outer hair cells, basilar membrane, cochlear amplifier

Front 40

___ can affect outer hair cells, which respond to sound with both ___[2]

Back 40

Motor proteins, a receptor potential and a change in length

Front 41

The motor protein is driven by ___, powered by ___

Back 41

Prestin, the membrane potential

Front 42

___ are sounds emitted by ears, with ones emitting loud ones particularly likely to have been affected by ___

Back 42

Optoacoustic emissions, cochlear damage

Front 43

The drug ___ decreases transduction that results from bending of stereocilia on hair cells, reducing the movement of the __

Back 43

Furosemide, basilar membrane

Front 44

There are also about ___ efferent fibers projecting from the brain stem toward the cochlea. These efferents diverge widely, synapsing onto outer hair cells and releasing ___. Stimulation of these efferents changes___, thereby affecting the responses of inner hair cells.

Back 44

1000, acetylcholine, shape of the outer hair cells

Front 45

Afferents from the spiral ganglion enter the brain stem in the auditory-vestibular nerve. At the level of the ___, the axons innervate the __[2]

Back 45

Medulla, dorsal cochlear nucleus, ventral cochlear nucleus

Front 46

Cells in the ventral cochlear nucleus send out axons that project to the ___ on both sides of the brain stem. Axons ascend in the ___ and innervate the ___ of the midbrain, while the dorsal path ___

Back 46

Superior olive, lateral lemniscus, inferior colliculus, bypasses the olive

Front 47

The neurons in the inferior colliculus send out axons to the ___ of the ___, which in turn projects to ___.

Back 47

Medial geniculate nucleus, thalamus, auditory cortex

Front 48

General points regarding nerves in the auditory system: ___[3]

Back 48

Many different pathways, extensive feedback, cochlear nucleus receives input ipsilaterally, but all others receive from both

Front 49

The neuron is most responsive to sound at one frequency, called the neuron’s ____, with different areas of the brain having different responses

Back 49

Characteristic frequency

Front 50

Information about sound intensity is coded in two interrelated ways:___[2], and the basilar membrane vibrates with ___ amplitude.

Back 50

The firing rates of neurons and the number of active neurons, greater

Front 51

Frequency sensitivity is largely a consequence of the mechanics of the ___; moving from the base to the apex of the cochlea, a progressive ___ occurs in the frequency that produces a maximal deformation of the basilar membrane.

Back 51

Basilar membrane, decrease

Front 52

Systematic organization of characteristic frequency within an auditory structure is called ___, analogous to ___ in the visual system.

Back 52

Tonotopy, retinotopy

Front 53

Reasons why frequency is coded in some way other than site of maximal activation in tonitopic maps: ___[2]

Back 53

Maps do not contain neurons with very low frequencies, basilar membrane is affected by both intensity and frequency

Front 54

The main source of information about sound frequency that complements information derived from tonotopic maps is the timing of ___, also called ___

Back 54

Timing of neural firing, phase locking

Front 55

Intermediate sound frequencies are represented by the pooled activity of a number of neurons, each of which fires in a ___ manner; this is called the ___, but above ___, frequencies are represented by tonotopy alone

Back 55

Phase-locked, volley principle, 4kHz

Front 56

Localization of sound in the horizontal plane can be due to ___[2], which together constitute the theory of ___

Back 56

Interaural delays, interaural intensity difference, duplex sound

Front 57

Lower frequency sounds use ___ in the horizontal plane, while higher ones use ___

Back 57

Interaural time delay, interaural intensity difference

Front 58

The first structure where binaural neurons are present is the ___

Back 58

Superior olive

Front 59

To measure timing differences as accurately as possible, many neurons and synapses of the auditory system are specially adapted for ___; their ___ are much faster than those of most other neurons in the brain.

Back 59

Rapid operation, EPSPs

Front 60

Recent studies on gerbils have suggested that ___, rather than ___, generates the sensitivity of superior olivary neurons to interaural delay.

Back 60

Synaptic inhibition, axonal delay lines

Front 61

Vertical localization of sound is largely due to the ___, although barn owls can use ___

Back 61

Pinna, different height ears

Front 62

In the MGN, Layer I contains ___, and layers II and III contain mostly ___. Layer IV, where the medial geniculate axons terminate, is composed of ___. Layers V and VI contain mostly ___

Back 62

Few cell bodies, pyramidal cells, densely packed granule cells, larger pyramidal cells

Front 63

In the tonotopic representation in A1, low frequencies are represented ___, whereas high frequencies are represented ___. Roughly speaking, there are isofrequency bands running ___ across A1.

Back 63

Rostrally and laterally, caudally and medially, mediolaterally

Front 64

The auditory cortex lesions are less dangerous because __

Back 64

Both ears project to cortex in both hemispheres

Front 65

___ is when a person hears sounds constantly

Back 65

Tinnitus

Front 66

All hair cells are contained within interconnected chambers called the ___

Back 66

Vestibular labyrinth

Front 67

The ___ detect the force of gravity and tilts of the head, and the ___ are sensitive to head rotation

Back 67

Otolith organs, semicircular canals

Front 68

The otolith organs are a pair of relatively large chambers, called the ___[2],

Back 68

Saccule, utricle

Front 69

Each hair cell of the vestibular organs makes an excitatory synapse with the end of a sensory axon from ___. There are about 20,000 vestibular nerve axons on each side of the head, and their cell bodies lie in ___

Back 69

Cranial nerve VIII, Scarpa’s ganglion

Front 70

Each otolith organ contains a sensory epithelium called ___, which has ___

Back 70

Macula, tiny crystals of calcium carbonate

Front 71

Each hair cell of the otolith organ has one especially tall cilium, called the __. The bending of hairs toward the kinocilium results in a ___

Back 71

Kinocilium, excitatory receptor potential

Front 72

The ___ sense linear acceleration and the ___ angular acceleration

Back 72

Otolith organs, semicircular canals

Front 73

The hair cells of the semicircular canals are clustered within a sheet of cells, the ___, located within a bulge along the canal called the ___. The cilia project into the gelatinous ___, which spans the lumen of the canal.

Back 73

Crista, ampulla, cupula

Front 74

Primary vestibular axons make direct connections to the __ on the same side of the brain stem, as well as to the ___

Back 74

Vestibular nucleus, cerebellum

Front 75

For example, axons from the otolith organs project to the ___, which then projects via the ___. This pathway helps the body stay upright even on the rolling deck of a boat. Axons from the semicircular canals project to the ___, which sends axons via the ___

Back 75

Lateral vestibular nucleus, vestibulospinal tract, medial vestibular nucleus, medial longitudinal fasciculus

Front 76

The vestibular nuclei send axons into the __ of the thalamus, which projects to regions close to the ___

Back 76

Ventral posterior nucleus, representation of the face

Front 77

___ keeps your eyes pointed in a particular direction

Back 77

The vestibulo-ocular reflex(VOR)