EAR

Question 1

In the inner ear we find…

Answer 1

Sensory organs for hearing and equilibrium

Question 2

Answer 2

Question 3

The source of sound causes movements of the … in its immediate neighbourhood; these movements cause disturbances in the air a little farther away from the source; these air particles in their turn affect their neighbours which are still farther away from the source; and so the disturbance spreads outward.”

Answer 3

air particles

Question 4

Answer 4

Depending on the sound, one part of the cochlea or the other activates.

Question 5

Sound reception and sound transmission is done by…

Answer 5

• The tympanic membrane
• The auditory or bony ossicles
• Oval Window

Question 6

Answer 6

Question 7

The bony ossicles:
- Modulate the movement of the …
- Apply force to the …– amplifying the incoming sound wave

Answer 7

• tympanic membrane
  -oval window

Question 8

The oval window transforms air pressure variations into…

Answer 8

Mechanical movements

Question 9

A sound is any … of air that could cause a displacement of the … which, after transmission by the bone chain, could affect the … in the inner ear in such a way that the auditory … are stimulated.

Answer 9

disturbance, eardrum, liquid, nerves

Question 10

Answer 10

Question 11

Answer 11

Question 12

What can we appreciate?

Answer 12

Scanning electron micrograph of the Organ of Corti. The hair- cell cell bodies are pseudo- colored blue

Question 13

Answer 13

Question 14

Answer 14

Question 15

Answer 15

Question 16

Hair cells in the cochlea can regenerate (T/F)

Answer 16

False: they cannot regenerate

Question 17

Sterocilia are connected through one another with …

Answer 17

TIPS. They are important so as to help other sterocilia to bend, touching the tectorial membrane and amplifying the sound.

Question 18

Hearing is initiated when … in air pressure are converted into fluid pressure that travel down the …

Variations in fluid pressure induce vibrations in the … that are transferred onto … cells

The … extends outward over the hair cells

When the basilar membrane and organ of Corti are displaced, … hit the tectorial membrane opening …. channels and depolarization of the hair cells occurs (opening Ca2+ channels). Then … occurs and K+ enters again.

Answer 18

oscillations, cochlear duct

basilar membrane, hair

tectorial membrane

sterocilia, potassium, repolarization

Question 19

Answer 19

Question 20

Action potentials in the VIII nerve keep a phase relationship with the sound stimuli,… for low frequencies and 1:n up to… KHz

Answer 20

1:1, 5
(100 vibrations/second=100 action potentials per second)

• IMPORTANT: Musicality is given by low frequencies

Question 21

Type I cells connect with…

Answer 21

1 Inner cell
(THEY ARE THE MOST IMPORTANT ONES)

Question 22

Type II cells connect with …

Answer 22

Several outer hair cells

Question 23

General characteristics of the auditory pathway

Answer 23

• Tonotopic organization: frequencies will be represented at different points in the pathway.
• Multiple comissures: we have comissures in the brain connecting several nuclei, the pathway is very bilateral. Although we also have contralateral connections.
• Parallel processing: it is done in the brainstem and not in the ear. Frequency, time, location, intensity… all these characteristics are also processed in the brainstem (there is a subpathway for each type of info)
• Descending projections: help to reduce the input of some sources of info and to increase the input of others (centramos la atención en una conversación aunque haya otras personas hablando).

Question 24

In the cochlear nuclei we find just one type of cell (T/F)

Answer 24

False: there are different types of cells. The same axon will connect with different cells and create parallel pathways.

Question 25

… is common to any type of neuron

Answer 25

PERISTIMULUS HISTOGRAM

Question 26

Tuning curve is measured for…

Answer 26

Soft sounds: if we increase the sound, we lose specificity. - Frequency selective= small tuning curve - Non-frequency selective= wide tuning curve

Question 27

To measure how a neuron responds to a specific intensity we use the…

Answer 27

Rate-intensity curve

Question 28

Superior olivary complex mainly … sound (function) Also the … are responsible for the descending olivocochlear path (descending pathway)

Answer 28

Localises. We can find: Medial olivary nucleus, Lateral olivary nucleus, Medial nucleus of the trapezoid body Preolivary regions.

Question 29

Which nucleus identifies? Intensity differences between ears (level detector) Useful for high pitch sounds Best developed in humans

Answer 29

Lateral superior olive and medial n. of the trapezoid body

Question 30

Which nucleus identifies? Phase (time) differences between ears (coincidence) Useful for low pitch sounds Less developed in humans

Answer 30

Medial superior olive

Question 31

With low pitch sound we can differentiate the …, and with high pitched the …

Answer 31

time, where it arrived first (right and left ear can be within the same cycle of the wave), intensities

Question 32

Answer 32

Question 33

Hearing: Turning Sound into Voltage - Changes in … induce fluid motions that travel along the cochlear duct and induce … at the … in the organ of Corti - Gradual changes in the physical properties of the cochlea from the base to the apex, each segment of the… in response to a specific frequency

Answer 33

-air pressure, mechanical vibrations, sensory epithelium -sensory epithelium vibrates

Question 34

Organ of Corti - …. element in the inner ear - Situated on the …

Answer 34

- Sensitive - basilar membrane

Question 35

ORGAN OF CORTI Sensory epithelia of the inner ear contain two major cell types:…

Answer 35

hair cells and supporting cells

Question 36

Answer 36

Question 37

Organ of Corti At the hair-cell basal pole are synaptic contacts with …

Answer 37

spiral ganglion neurons

Question 38

Name the structure

Answer 38

Organ of Corti

Question 39

SUPPORTING CELLS ORGAN OF CORTI - … cells that reside between hair cells - Span the entire depth of the …: from the basal lamina to the lumen - Linked to each other and to hair cells by … junctions - They communicate directly with other supporting cells by …

Answer 39

- Non-sensory - epithelium - tight and adherens - gap junctions

Question 40

Membranous Labyrinth - Filled with … - Various … – specializations of the epithelium

Answer 40

- endolymph - sensory structures

Question 41

Membranous labyrinth

Answer 41

Question 42

Answer 42

Question 43

Semicircular Ducts - Continuous with and arise from the … - … semicircular ducts: perpendicular to each other so that they can detect angular acceleration of the head in three-dimensional space

Answer 43

- utricle - Three

Question 44

What can we appreciate in this image?

Answer 44

Semicircular ducts

Question 45

An 18-year-old man experiences seasickness while on a deep-sea fishing excursion. What does he have? What structure is involved?

Answer 45

He has VERTIGO. The structure involved is the MACULA. It is an overstimulation of STEROCILIA.

Question 46

Which cells of the cochlea are responsible for converting vibration into a nerve signal?

Answer 46

Inner cells

Question 47

Which cells in the cochlea are responsible for acting as an amplifier? Regulating the vibration of the tectorial membrane and helping to detect the signal correctly.

Answer 47

OUTER HAIR CELLS

Question 48

From certain frequencies onwards (…), the action potential in the ear gets sent every 2/3 vibrations.

Answer 48

5kHz

Question 49

Auditory neurons have their some located at…

Answer 49

Spiral ganglion in cochlea.

Question 50

Type 1 auditory neurons synapse with…

Answer 50

1 single inner cell

Question 51

Type II auditory neurons synapse with…

Answer 51

Many outer hair cells

Question 52

Input from the auditory nerve will reach the cochlear nuclei: They are located in…

Answer 52

- VENTRAL COCHLEAR NUCLEI (VCN) - DORSAL COCHLEAR NUCLEI (DCN) junction between medulla and pons, near the pontocerebellar angle (where VII and VIII enter or exit the brainstem)

Question 53

AUDITORY PATHWAY The … is the 1st relay pathway. The auditory nerve synapses in it with different cellular types, which initiate parallel processing of different characteristics. Each type of info will go to relay centers and all converge back in the … .

Answer 53

cochlear nucleus, inferior colliculi

Question 54

LATERAL LOCALIZATION FOR LOW-PITCHED SOUNS The neurons located in the superior olive receive … of different length: it depends on the LENGTH MSO neurons fire when the input from both ears is… (coincidence detectors). There are different “delays” in the conduction time through the axons of the spherical cells to each MSO cell. Each MSO neuron represents therefore a different point in space in the lateral plane.

Answer 54

R and L axons simultaneous

Question 55

LATERAL LOCALIZATION OF HIGH-PITCHED SOUNDS When the intensity of the sound is higher in one ear compared to the other, the excitatory input from the ear with the louder sound … the inhibitory input from the ear with the softer sound, causing the firing of the ipsilateral LSO (lateral superior olive).

Answer 55

overcome

Question 56

DESCENDING AUDITORY PATHWAYS

Answer 56

- OLIVOCOCHLEAR BUNDLE: both medial and lateral olivocochlear efferences - CORTICO-THALAMIC PROJECTIONS. - CORTICO-COLLICULAR PROJECTIONS: filter system. - DESCENDING PROJECTIONS FROM THE INFERIOR COLLICULUS.

Question 57

OLIVOCOCHLEAR BUNDLE Medial efferences connect with… hair cells Lateral efferences connect with … and inner hair cells

Answer 57

Outer Type I olivocochlear neurons

Question 58

Lateral lemniscus-auditory system Which nucleus is responsible for temporal processing and ONLY receives input from the contralateral ear?

Answer 58

VENTRAL NUCLEUS OF THE LATERAL LEMNISCUS

Question 59

NUCLEI OF THE LATERAL LEMNISCUS IN THE AUDITORY PATHWAY

Answer 59

VENTRAL AND DORSAL NUCLEUS OF THE LATERAL LEMNISCUS

Question 60

Point where all the auditory pathway converges

Answer 60

INFERIOR COLLICULUS

Question 61

Which nucleus of the inferior colliculus carries out frequency processing (in a tonotopic manner) and has narrower tuning curves?

Answer 61

CENTRAL NUCLEUS

Question 62

Which part of the inferior colliculus participates in integrative processes?

Answer 62

CORTICES

Question 63

Which motor structure integrates sensory inputs from different pathways orienting responses towards images or sounds?

Answer 63

SUPERIOR COLLICULUS

Question 64

BRAINSTEM AUDITORY EVOKED POTENTIALS is…

Answer 64

A test that helps us explore auditory pathways

Question 65

Answer 65

Question 66

MEDIAL GENICULATE BODY- THALAMUS. WHICH DIVISION? Glomerular organization Tonotopic distribution Narrow (even “closed”) tuning curves Projects to primary auditory cortex

Answer 66

VENTRAL DIVISION

Question 67

MEDIAL GENICULATE BODY- THALAMUS. WHICH DIVISION? Polimodal integration areas Auditory afferences (IC cortex), but also afferences from other modalities Projects to secondary auditory cortex and associative areas

Answer 67

Dorsal and medial divisions

Question 68

Primary auditory cortex corresponds to area…

Answer 68

41

Question 69

Secondary auditory cortex corresponds to area…

Answer 69

42

Question 70

Which auditory cortex has: Tonotopic organization Binaural responses Contralateral connections through corpus callosum Cortical, thalamic and collicular projections And is EXCLUSIVE

Answer 70

Primary auditory cortex

Question 71

Which auditory cortex is an association cortex and is not exclusive?

Answer 71

Secondary auditory cortex

Question 72

Cortical plasticity is only present until the ages of…

Answer 72

3 and 4. If a child has a problem in the primary cortex which recovers after this age, it will not be able to connect to secondary cortex. If a blind child recovers vision, even though he knew braille, he would not be able to read because 1ary cortex has not developed.

Question 73

The organ of Corti allows

Answer 73

frequency coding

Question 74

Auditory parallel processing begins in the…

Answer 74

cochlear nuclei

Question 75

The superior olivary complex mediates… - Low pitched sounds: … (MSO) - High pitched sounds: … (LSO)

Answer 75

Lateral localization - phase - intensity

Question 76

…. Participates in temporal pattern recognition

Answer 76

Ventral nucleus of the lateral lemniscus

Question 77

The … has a central nucleus and peripheral cortices

Answer 77

Inferior colliculus

Question 78

The … has functionally relevant subdivisions

Answer 78

medial geniculate body

Question 79

There are primary (BA …) and secondary (BA…) auditory cortices

Answer 79

41, 42