Chapter 9.3-Inner Ear

Question 1

Inner Ear Function

Answer 1

Translates sound pressure waves into neural signals that are then transmitted to the brain for processing and interpretation as sound.

Question 2

What is the function of the inner ear analogous to?

Answer 2

Retina with respect to light wave in vision; both structures translate information carried by waves into neural signals

Question 3

Cochlea Function

Answer 3

Converting sound vibrations into electrical signals that our brain can understand.

Question 4

Structure of Cochlea

Answer 4

Contains the organ of corti and filled with watery fluids in three parallel canals

Question 5

Tympanic Canal (Scala tympani): Location

Answer 5

Lower chamber of the cochlea extends from apex of the cochlea to the round window

Question 6

Tympanic Canal (Scala tympani) Function:

Answer 6

Transmit sound vibrations that pass through the cochlea, ultimately leading to the round window, which is an opening that allows for the dissipation of pressure.

Question 7

Vestibular Canal- scala vesitbuli: Location

Answer 7

Upper chamber of a cochlea, extends at the oval window at the base of the cochlea to the helicotrema at the apex

Question 8

Scala Vestibuli Function

Answer 8

Transmit sound vibrations from the middle ear to the inner ear (cochlea through oval window) and plays a role in maintaining balance

Question 9

Middle Canal(endolymph) - scala media: Location

Answer 9

Middle chamber of the cochlea

Question 10

Scala media function

Answer 10

Houses the organ of Corti, which contains specialized hair cells that detect sound vibrations and convert them into electrical signals that are then transmitted to the brain for hearing.

Question 11

What are both the tympani and vestibular canals filled with? And connected by?

Answer 11

Filled with perilymph and connected by a small opening called the helicotrema

Question 12

Waht specalized tissue lines one side of the middle canal? What do these specalized tissues do?

Answer 12

Straia vascularis, maintain the right balance of charged ions in the endolymph to keep hair cells working at their best

Question 13

What are the three canals of the cochlea that are separated by the two membranes?

Answer 13

1) Resinne’s membrane
2) Basilar membrane

Question 14

Resinne’s membrane

Answer 14

Thin sheath of tissue separating the vestibular and middle canals in the cochlea

Question 15

Basilar membrane

Answer 15

A plate of fibers that forms at the base of the cochlear partition and separates the middle and tympanic canals in the cochlear

Question 16

How do travelling waves flow through the inner ear?

Answer 16

Travelling waves flow through the fluid in the vestibular canal, similar to a loudspeaker moving air to create sound waves.

Question 17

What happens to pressure changes in the cochlea?

Answer 17

Pressure changes create a displacement or “bulge” in the vestibular canal from the base to the apex of the cochlea,

Question 18

What happens if sounds are extremely intense?

Answer 18

Intense sounds pass through the helicotrema and back to the cochlear base through the tympanic canal, relieving pressure at the round window.

Question 19

The function of the round window:

Answer 19

Acts as a relief valve, allowing the release of excess pressure remaining from extremely intense sounds, preventing damage to delicate structures.

Question 20

Question: Where is the basilar membrane located?

Answer 20

Answer: It lies at the bottom of the middle canal.

Question 21

Organ of Corti Function

Answer 21

Responsible for converting sound vibrations into electrical signals that our brain can interpret as sound.

Question 22

Organ of Corti Structure

Answer 22

On the basal membrane of the cochlea that is composed of hair cells and dendrites of auditory nerve fibers

Question 23

Hair cells:

Answer 23

Secialized cells in the inner ear that use their stereocilia to convert mechanical movements into neural signals sent to the brain.

Question 24

Auditory Nerve:

Answer 24

nerve responsible for transmitting auditory information from the inner ear to the brain.

Question 25

Sterocillia

Answer 25

Hair like extension of tips of hair cells in the cochlear that when flexed, initiate the release of neurotransmitters

Question 26

Tecotiral membrane: Location

Answer 26

On top of the organ of Corti in the inner ear. It is a gelatinous structure that plays a crucial role in the process of hearing

Question 27

Tectorial Membrane Function

Answer 27

Allows the hair cells in the inner ear to detect sound vibrations by bending their stereocilia back and forth when it moves in response to sound.

Question 28

How does the tectorial membrane move?

Answer 28

The tectorial membrane moves sideways when the partition of the cochlea moves up and down.

Question 29

What is the role of the tectorial membrane in hearing?

Answer 29

The tectorial membrane helps to convert sound vibrations into neural signals that are sent to the brain for hearing.

Question 30

How is the tectorial membrane related to the basilar membrane?

Answer 30

The tectorial membrane rests on top of the organ of Corti, while the basilar membrane lies beneath it. Both membranes are involved in the process of converting sound vibrations into neural signals for hearing

Question 31

Cochlear Partition

Answer 31

The combined basilar membrane, tectorial membrane, and organ of Corti, which are together responsible for the transduction of sound waves into neural signals.

Question 32

Hair cells in the cochlear partiion convert _____ energy into _______ firing

Answer 32

sound pressure; neural firing

Question 33

How do photoreceptors and stereocilia in the cochlea differ?

Answer 33

The retina has more photoreceptors compared to the number of stereocilia in each cochlea, and stereocilia are faster and more sensitive than photoreceptors.

Question 34

What are stereocilia connected by?

Answer 34

Stereocilia in the cochlea are connected to each other by tiny filaments called tip links

Question 35

How do our ears and eyes differ in their sensitivity to changes in light and sound?

Answer 35

Our ears are always ready for the slightest sound due to the high sensitivity and fast response of stereocilia, while our eyes may take some time to adjust to a fully dark environment due to the slower response of photoreceptors.

Question 36

What is the result of depolarization in the hair cell?

Question 37

What completes the process of translating sound waves into neural activity?

Answer 37

The firing of the auditory nerve fibers, triggered by the release of neurotransmitters from the hair cell, completes the process of translating sound waves into patterns of neural activity.

Question 38

Summarize the process of hair cell activation:

Answer 38

It involves the deflection of stereocilia, opening of ion pores, influx of potassium and calcium ions, release of neurotransmitters, and firing of auditory nerve fibers.

Question 39

What is mechanoelectrical transduction?

Answer 39

conversion of mechanical stimuli or vibrations into electrical signals or energy.

Question 40

How does this mechanoelectrical transduction in hearing differ from phototransduction?

Answer 40

Depolarization in hearing does not await a cascade of biochemical processes such as those in photoactivation